One of the things climate scientists worry about is feedback mechanisms. Some feedbacks are positive- they amplify warming, and some are negative - they suppress warming. Let's take a quick look at a graphic showing how cold air is made. Basically, what this graphic is showing us is that at this time of the year, when the Arctic is receiving little sunlight, the radiative input is less than the radiative output. In other words, more energy leaves the Earth than is added by the sun and cooling occurs.

In addition to that part of the equation, the radiative output (energy lost) is increased by the snow and ice on the ground. Anyone who has experienced snow knows how well it reflects light. It is possible to become "snowblind" from exposure to the bright sunlight and UV rays reflected by the snow. You see, it's not just the light that is reflected by snow, it is also the other portions of the sun's energy, including it's heat that is reflected away from the Earth's surface.

So what does this have to do with global warming? You have probably heard about concerns over the diminishing ice in Greenland and elsewhere in the Arctic as well as in Antarctica. In areas where the ice melts, revealing land or ocean beneath it, less of the sun's heat is reflected back to space and more is absorbed. Since it is the sun's energy absorbed by the Earth that warms the atmosphere, the melting ice can become a positive feedback and cause the Earth to warm faster.

We all know carbon dioxide, a naturally occurring chemical - the product of the respiration of every animal on earth - which is also produced by the burning of fossil fuels such as oil, coal and natural gas. And some of us may have also heard about methane, another of the greenhouse gases, which may also have a significant role in global warming over the next few decades (I'll post more on methane another day - it gives me a headache). But today from Japan comes a report on yet another greenhouse gas. Dinitrogen oxide, which originates from nitrogen-based fertilizers used on farms. The chemical was measured through the use of ice cores taken from Antarctica and has been increasing slowly for the past 50+ years.

Little darlin' - oh, sorry. Beatles tangent. What if the sun and it's energy variations have more to do with climate change than any greenhouse gasses? Seem unlikely? Maybe, but there are certainly a number of scientists who are looking into these links. Elliot Abrams noted some in his blog in September. Here's a link to a lecture by Sallie Baliunas, Ph.D. from back in 2002. In the interest of being forthright, I will state here that some are critical of Dr. Baliunas' connections to the Marshall Institute, which receives a fraction of it's funding from oil companies (or at least from Exxon-Mobil).

And here's a link I got from Jesse Ferrell's blog back in September to an article about upcoming global COOLING, based on solar emission research.

By the way, Jesse's blog has some of the best weather pictures around. Check it out! And thanks to all our site visitors who have contributed pictures to our AccuWeather.com photo gallery. There's a lot of beautiful shots there, including this one which seems appropriate today.

When in read a summary of this article from the Denver Post, and it mentioned hurricane expert Dr. Bill Gray, I expected an explanation of Dr. Gray's well-known skepticism over global warming. What I got was a whole lot more. A very sound overview of the difficulties of modeling the climate, and an unbiased representation of both sides of the global warming issue. Read this one, folks. It's worth the time.

I've had some questions about the greenhouse effect and greenhouse gases, so I figured now would be as good a time as any to provide a little overview of the subject.

First of all, it's important to note that the greenhouse effect and global warming are NOT the same thing. Greenhouse gases and the greenhouse effect have always been with us, and in fact makes the Earth habitable. If the Earth had no atmosphere, it would average about 30 degrees Celsius (about 50 degrees Farenheit) lower than it does at present.

(Image From Global Warming Art)

So how does the atmosphere help keep the Earth warm? Most of the sun's radiation has a short wavelength. It's mostly in and near the visible parts of the spectrum. The atmosphere is mostly transparent to visible light, which is absorbed by the Earth's surface. As the surface warms, it radiates longer wavelength radiation which warms the atmosphere. Those areas which receive more sunlight warm the most, and land warms much faster than water. And of course, some surfaces on the land absorb more of the sun's radiation and heat up faster, as anyone who has walked from a grassy park onto an asphalt parking lot on a hot July afternoon knows. The radiation absorbed by the atmosphere is then emitted in all directions, some going back to Earth, some going out to space. This whole process is complicated further by the presence of clouds, which can reflect some of the incoming solar radiation and can also prevent the day's heating from escaping back to space at night.

Greenhouse gases include water vapor (the most abundant by far), carbon dioxide and methane. The concern among many climate scientists is that increasing amounts of CO2 will increase the overall global temperature (global warming) and have a damaging effect on the Earth's climate.

Here's a good resource on bad greenhouse meteorology.

As I mentioned before, I've spent almost 20 years forecasting the weather. That means I've spent WAY too much time looking at computer models. I'm enough of an old-timer to remember the baroclinic and the LFM, though of course I have had much more experience with the NGM, the ETA (NAM, WRF, whatever they're calling it this week) and the longer range models like the European and the GFS.

Those years of experience have taught me two things. First, computer models have glaring weaknesses. Some would say they stink. Some would say worse. There is just so much complexity in the atmosphere which has to be simplified for the sake of number-crunching time that they can't capture everything that happens. And sometimes that results in massive error. Second, meteorologists can't function without them. While I still think you get more accuracy in the first 6-12 hours of a forecast by looking at the NOW - satellites, radar, surface and upper level charts - the models are better than "classical methods" farther out. So it's sort of a love-hate relationship.

Climate models are really a different animal from weather forecasting models, but it's difficult for my forecaster brain to get away from my feeling that models are not entirely to be trusted. Nonetheless, models are one of the primary methods climate scientists use to predict climate change. Here's an excellent overview of what climate models are and how they work from Gavin Schmidt, a climate modeller at the NASA Goddard Institute for Space Studies.

Now if you really want to have fun.....and you have a half-way decent PC (or Mac) that can be pretty much dedicated to a project for a couple of days, you too can become a climate modeller! Columbia University has an educational Global Climate Model which uses NASA GISS' GCM II but can be run on a desktop. This software was developed for use with students from 9th grade through grad school. Any teachers reading this may be interested in using this tool in their classrooms.

Just a couple of notes on this model, I downloaded it a couple of weeks ago on a Friday and ran it on my rather elderly, 400 MHz processor Mac. It ran like a top - no problems with it even though I had to work a rare forecasting shift on Saturday and I had multiple applications running with the GCM in the background. However, it took from Friday evening to midday Monday to run a 50 year simulation. I would love to see what I could do running this on a newer system with something near 2 GHz processing speed. There are a bunch of simulations which can be run if you've got the speed to do it.

The American Meteorological Society has drafted a statement on Climate Change. The statement can be found by following the link halfway down the page. Members of the AMS are welcome to submit their comments to the AMS Council. The statement is a fairly complete overview of the AMS' opinion.

Ahhhhh.....methane. What could be a better topic for today? I wish I knew, because methane is one of the most difficult topics around when it comes to greenhouse gases. Well, first the good news. A new study, summarized here, finds that atmospheric methane has stabilized, possibly due to leak repairs at oil and gas pipelines and storage facilities and perhaps from reduced or slower growth of emissions from coal mining, natural gas production and rice paddies. Methane is also released into the atmosphere by a number of natural phenomena, such as biomass burning, volcanic eruptions and the melting of methane hydrates in permafrost. Oh, and it also results from cows - as Henry noted in a November 6th entry on his MeteoMadness blog.

The fact that methane is currently stable in the atmosphere is a good thing, but this entry at RealClimate.org makes it fairly clear that our understanding of methane variations is limited, to say the least. We simply can not use the data we have now to construct any sort of accurate forecast for future methane concentrations. Given that methane is a more potent (though shorter-lived) greenhouse gas than carbon dioxide, and given that methane in the atmosphere oxides into carbon dioxide, this is another area where more research is needed.

I'm not sure how many of the readers of this blog follow up and read comments, so I thought I would add this link to an entry on the main page. Thanks to Sarah Fortner for adding it to our discussion. This is an op-ed piece from Peter Doran, an associate professor of earth and environmental sciences at the University of Illinois at Chicago. It was his research which discovered the regional cooling in portions of Antarctica. The op-ed addresses how this research has been mis-used by the media and others as "evidence" against global warming. It makes a very interesting read.

I don't know how many of you have followed up with the story I linked a couple of days ago, so here is a reminder about the MSNBC reporter and photojournalist visiting Antarctica. They are there to observe a massive drilling project going on there. I'm linking the second page of the article, because that's the story of his journey to Antarctica. The first page then tells the story of the reporters first trip onto the Ross Ice Shelf. If you follow the link to the interactive page, you can listen to a lot of information about Antarctica and what makes it so interesting to researchers.

Here is a map to get you acclimated with the scene. The men are staying at McMurdo Station, which is located near the coast along the bottom of this image (tempting to say southern coast, but that would not be accurate!). McMurdo is located right at the rim of the Texas-size Ross Ice Shelf. That ice shelf sits over the water and helps to hold back the ice which is over land on Antarctica. If it were to break away from the continent, some of the ice on land would slip into the sea as well.

RealClimate has a post from last week which offers some new information on the "Little Ice Age" - the period of cooling, at least in the Northern Hemisphere, which occurred between the late 16th and some say the late 17th century. Others argue the LIA ended in the mid-19th century.

A study published in Nature by Lund et al (subscription required) explains how examination of the remains of tiny animals called foraminifera in sediments off the coast of Florida reveal the Gulf Stream, at least through the Florida Straights, may have weakened by about 10% during the LIA.

Lund and his colleagues think that a shift in the zone of tropical rains (bringing fresh water into the ocean) caused the Gulf Stream to weaken. As we've noted here before, there are concerns that the melting of the Greenland ice sheet could slow the Thermohaline Circulation much more dramatically and cause more significant effects on the world's climate.

I think that I shall never see
a poem lovely as a tree

So wrote Joyce Kilmer in 1913.

We've all enjoyed the shade of a tree on a hot summer day, appreciated the beautiful colors of autumn, watched in the spring as the leaves unfold again. Are more trees the answer to sequestering carbon and controlling climate change?

Seems the answer to this is more complicated than a simple yes or no. Results of a new study presented at the annual meeting of the American Geophysical Society in San Francisco on 15 December indicate that the location of the trees is tremendously important. Govindasamy Bala of Lawrence Livermore National Laboratory used computer models to simulate the effects of removing trees from the globe. The models used not only the carbon-storing capacity of trees, but also account for the release of water vapor by the trees (which enhances cloud formation) and the extra heat absorbed from the sun by the foliage which is usually darker than the ground beneath the trees. Read that last one again. Extra heat absorbed - that's a mark against the trees, as it's absorbed heat rather than reflected heat.

The results? Trees in the tropics are better at storing carbon than their mid-to-high latitude counterparts; the trees in the extra-tropical regions actually contributed to warming, as the heat they absorb more than counterbalances the CO2 they store. Everyone sees that forests have many other benefits beyond serving as CO2 sinks, but if you are contributing to a reforesting campaign, you may want to consider turning your dollars toward the tropics.

Another factor which was not addressed at all within this study is the added benefit of shade trees planted around homes. I would think the energy saved from reducing the need for air conditioning would counterbalance the heat the tree absorbs.

A tip of the hat to commenter Greg today for sending me a link to an interesting article from the Houston Chronicle. The article raises the question, have climate scientists overplayed global warming?

Various weather events in the past couple of years, the 2005 hurricane season, summer heat waves and the unusual warmth of the early part of this winter in many areas come to mind, have brought a lot more attention to the field of climate study. Some scientists are concerned that the information being presented to the public is being miscommunicated.

In particular, some scientists are concerned that the uncertainty that exists within climate science is not being communicated clearly, and that instead the message that gets to the public is a message of absolutes. The article makes it refreshingly clear that there are plenty of elements in the climate which are not understood.

Scientists have substantial evidence to support the view that humans are warming the planet - as carbon dioxide levels rise, glaciers melt and global temperatures rise. Yet, for predicting the future climate, scientists must rely upon sophisticated - but not perfect - computer models.

"The public generally underappreciates that climate models are not meant for reducing our uncertainty about future climate, which they really cannot, but rather they are for increasing our confidence that we understand the climate system in general," says Michael Bauer, a climate modeler at NASA's Goddard Institute for Space Studies, in New York.

The article concludes by asking if some younger scientists aren't free to contradict older, more established scientists, who may hold sway over the grants needed to fund research. A fair question to ask, I think.

A brief article from Reuters summarizes some of the contents of the IPCC's 4th Assessment report, coming out next week. The primary changes from the previous assessment highlighted here are a tightening of the projected temperature increase from pre-industrial levels to 2 to 4.5 degrees Celsius (3.5-8 degrees F) from the previous estimate of 1.4-5.8 degrees C (2.5-10.4F) and a slower sea level rise. The new assessment predicts a sea level rise this century of less than 50 cm, as compared to a prediction of 9-88 cm in the 2001 assessment.

I had a chuckle at this quote:

The European Union and many environmental groups want the world to cap any rise in temperatures at 2 degrees C (3.6 F) over pre-industrial levels, saying such a rise would cause dangerous changes to nature such as more heat waves.

Cap temperature rise? As humans, we can cap our emissions, but that's about the best we can do. Temperatures will do as they will.

Reuters also published an article previewing the IPCC report by using some estimates of global implications of temperature rise based on Britain's Stern Report, published back in October. The thing that struck me from the numbers was the amount of uncertainty. A 3 degree temperature rise would subject 1-4 billion "more" people to water shortages. That's quite a large range. We meteorologists hear complaints if we forecast 6-12 inches of snow.

The IPCC report will be 1600 pages long. Just a little light reading.

A tip of that hat to commenter Steve G. for pointing me to an article from yesterday on an Australian study predicting a deadly spike in temperatures by 2070. The Commonwealth Scientific and Industrial Research Organization said average annual temperatures in Sydney will rise from the current 78.8 to around 88 by 2070. The rise in temperatures could increase heat-related deaths in people over 65 from the current average of 176 per year to over 1,300 per year, and droughts and fire risk would increase as well.

The study was commissioned by New South Wales, the state that includes Sydney.

Australia's prime minister, John Howard, has been repeatedly criticized for not ratifying the Kyoto Protocol in 1997, making Australia and the Unitie States the only major industrial nations to reject the treaty. China and India were deemed "developing" and thus exempt from Kyoto's restrictions.

Australian power companies issued a report Wednesday saying the best way to slow greenhouse emissions is through the use of nuclear power and retrofitting coal-fired plants to capture carbon dioxide. Prime Minister Howard agreed with those findings.

The first volume of the IPCC's Fourth Assessment Report (AR4) was released late last night. I'd recommend everyone with an honest interest in the most up-to-date climate science take the time to listen to the webcast of the press conference and read the 21 page Summary for Policymakers. I will be reading the summary and commenting on it later today.

After some delay, I've finished the IPCC Working Group 1 Summary for Policy Makers, which discusses the physical science basis of the 4th Assessment report. The summary is not very heavy in the actual science, being written for nonscientists. I'd recommend people with an interest in the subject of global warming and in the debate over global warming policy take the time to read the summary. If 21 pages seems too overwhelming, I'd especially point to pages 10-13, the Projections of Future Changes in Climate and to the figures on pages 15 and following.

For those who will only read a few pages of the report, I'd like to summarize some of the abbreviations used in the report used in the report. TAR is the Third Assessment Report, the IPCC's 2001 report on climate change. AR4 is the 4th Assessment Report. SRES is the IPCC Special Report on Emission Scenarios. The summary uses terms to describe mathematical probabilities, with Virtually certain > than 99% probability of occurrence, Extremely likely >95%, Very likely >90%, Likely >66%, More likely than not >50%, Unlikely <33%, Very unlikely <10%, Extremely Unlikely <5%. Very high confidence is at least a 9 out of 10 chance of being correct and high confidence about 8 out of 10 chance of being correct.

The summary includes references (in the squiggly brackets) to the chapters in the full report where each point is supported. I wish I had access to the whole thing, but at this point I don't.

As has been widely reported, the conclusions of the summary are that warming is happening, and humans are "very likely" to blame for it. It's hard for me to assess the evidence without access to the full report - like everyone else, I have to take the summary at its word. I know that many of the regular readers here are cynical to say the least about anything that comes out of the U.N. I choose to believe these scientists have no ulterior motives.

It is clear from reading the summary that, if these scientists are correct, warming will be with us for a long time, no matter what we do about our emissions. Thinking about ways to adapt to our changing climate may be equal in importance to coming up with ways of cutting emissions.

In a related story, the UK's Guardian Unlimited reported Friday that scientists have been offered cash by lobby group/think tank American Enterprise Institute (AEI) - a group funded by ExxonMobil - for articles undermining the IPCC report.

Elliot Abrams gave me a call yesterday. "I've found an article that you should read," he said. It's from the January 30 issue of EOS, which is the weekly newspaper of the American Geophysical Union. I would link the article, but I'm not a subscriber. Elliot faxed me the hard copy of the article, titled A Perspective on Global Warming, Dimming and Brightening.

Global dimming is the reduction of solar radiation measured at the Earth's surface, which has been observed since the beginning of systematic measurements in the 1950s. That trend may have reversed over the past decade or so. It's believed that global dimming is probably due to an increase in aerosol particles in the atmosphere, but aerosols' impact on global temperatures continue to be poorly understood. The reduction in solar (shortwave) radiation from 1958 to 1992 was 20 watts per square meter, far more than the 2.4 w/m² increase in the positive longwave forcing believed to have occurred due to increases in greenhouse gases since the dawn of the industrial age.

The EOS article, written by Gerald Stanhill, raises questions about the IPCC, which has never, at least through the Third Assessment Report, made reference to changes in solar radiation at the Earth's surface. Considering that solar radiation is the primary driver of climate, Dr. Stanhill questions "the confidence that can be placed in a top-down, 'consensus' science system that ignores such a major and significant element of climate change."

Danish researcher Henrik Svensmark believes cosmic rays are affecting the world's climate, producing much of the warming we've observed in recent years.

Svensmark, a researcher at the Danish National Space Center, believes that a relative minimum of cosmic rays are leading to a reduction in cloud cover. Clouds help cool the planet by reflecting some of the incoming solar radiation. Svensmark's research shows that cosmic rays produce electrically charged particles in the atmosphere which attract water molecules and eventually lead to the formation of clouds. More information about the research can be found at the SKY experiment's homepage.

Even though Svensmark believes these cloud changes are having a significant effect on the climate, it's important to note he does not deny that humans are having an impact on the climate.

He claims carbon dioxide emissions due to human activity are having a smaller impact on climate change than scientists think. If he is correct, it could mean that mankind has more time to reduce our effect on the climate.

Some cloud specialists disagree with Svensmark's findings. I think it is worth further investigation.

NOAA has released a report on the climate in January of 2007. Globally, it was the warmest January on record. Eastern Europe and Russia were especially far above normal, and those areas experienced well below normal snow cover. U.S. temperatures for the month as a whole were near normal. Many places in the central and eastern United States started the month with temperatures well above normal, then experienced a sharp change to colder weather.

As always, one day, one month, one season, even one year does not prove anything about long term climate change. It's only when we see trends lasting for multiple years, even decades that we can state with confidence that the climate is changing.

On Monday, New Scientist posted an article that summarizes the latest "greenhouse gas" research from the Arctic. Kim Holmen, research director of the Norwegian Polar Institute, which oversees a measuring station 750 miles from the North Pole, is quoted as reporting that levels of carbon dioxide "are at a new high" and are increasing at accelerating rate. Holmen attributes this steep rise to the rapid growth of Asian economies, particularly China and its use of coal-fired plants. The article also reports that "Scientists say the concentration of CO2 in the atmosphere is at its highest in at least 650,000 years," though it provides no attribution to this statement.

I've had a number of comments and reader e-mails lately asking what we know about past climate and how we know it. So I thought now would be a good time to talk a little big about the field of paleoclimatology, that is, the study of past climate. The link that I've provided gives a fairly comprehensive overview from NOAA, covering how climate is studied and what we know.

A foundational tool of paleoclimatology is proxy records. A wide network of instrument records of the weather extends back only slightly more than 100 years. How can we know what the weather was in the more distant past? Paleoclimatologists study natural recorders of climate - tree rings, ice cores, corals, fossil records - things which capture information about temperature and precipitation which can be studied and turned into a climate reconstruction.

NASA has an interesting "chapter" history and desciption of paleoclimatology which explains some of the methods of the science and explaining why it is important to understand the past in order to predict the future.

I doubt that paleoclimatology is ever taught at the 100-level in college; however, if it were, then Dr. Richard Alley, Evan Pugh Professor of Geosciences at Penn State, would be one of the best instructors to have. Dr. Alley, who studies paleoclimates from ice cores and who is one of the authors of the IPCC's 4th Assessment, has kindly taken time to answer some questions for the blog. Because of length, I will have additional answers in future posts.

Question: Dr. Alley, you study ice cores. Other paleoclimatologists study tree rings, coral, fossil records and sediment cores. Are all those sources taken into account when creating a climate record, or would a climate reconstruction be produced from each source?

Answer: Yes, and yes.

Typically, a researcher or group of researchers will develop a climate record based on one or a few cores. This most typical is a local climate record, giving for example the temperature at the site where the core was collected. (As you might imagine, there are careful analyses that go into such a statement--if you are relating pollen to temperature, then the temperature you infer from the pollen present represents conditions over the region from which the pollen blew to your core; if you are studying indications of temperature in an ice core, then the motion of ice--glaciers flow--may have brought samples from somewhat higher elevation. These sorts of complications are generally handled in the technical literature, scientists love to argue about them, and so we probably do a pretty good job with them.)

Once many such records are developed, they are pieced together to reconstruct regional or global temperature. Some selectivity is often used in this. For example, in the studies of the most recent millennium, some workers have restricted themselves to annually resolved records (those in which the age is really known to the year). This is valuable, in that it avoids any problems with estimation of ages (is this wiggle in my core really the same climate event as that wiggle in your core?), but it loses information from cores that, say, have 10-year dating accuracy. So other groups have assembled lower-time-resolution histories from lower-time-resolution archives.

This is a little more technical, but.... As you go older, annually resolved records become rarer and rarer, so we use other approaches. For example, in an ice core from Greenland, we obtain indications of the temperature in Greenland, but we also see changes in the dust of the atmosphere. People have carefully looked at the isotopic, chemical, etc. composition of the dust, and it came from Asia (from the high plateaus of central Asia, blowing to the high ice sheet of Greenland). There are HUGE changes in the dust (10-100 fold), and explanations of the dust changes all invoke changes in the source in Asia (you could change how much falls out on the way, for example, but it is hard to find a reasonable model that "works" to give the very large Greenland changes). So, we infer that there were changes in the Asian dust source, probably linked to wet/dry (with more dust when the rains stop). So, people go to Asia, and they develop records of wet and dry, and find that the record of wet/dry in Asia looks like the record of dusty/not in Greenland ice, agreeing in size of changes, duration of changes, and in age of changes, within the uncertainties in knowing exact ages. So we then believe we can "tweak" the age estimates, within the known uncertainties, to improve the correlation.

I read a lot about how we can't "prove" global warming using the scientific method. That's true. We can't experiment on the climate. There is, after all, only one Earth with only one atmosphere. That's where climate models come in. Models are very complex numerical representations of the climate. The more complex the model, the more computing power is needed to run it. They create, in effect, virtual Earths that modellers can experiment with.

Since climate modelling is so central to climate prediction, it only makes sense to stop and take a look at what climate models are and how they are developed and tested. The UK Met Office's Hadley Centre provides an overview of different types of climate models, from simple to complex.

Gavin Schmidt of NASA Goddard Institute for Space Studies has written an excellent, readable overview of the physics of climate modelling which briefly covers the history and development of climate models and explains the difference between weather forecasting models and climate models. Weather is chaotic, climate is stable.

Climate models are tested primarily with the present, particularly from 1979 on, when satellite data became readily available. Climate models, like weather forecasting models, seem to work best when taken as ensembles - the average seems better than any one whole - ironically, this is often the case with humans as weather forecasters as well.

Weather forecasting models have improved markedly in my 20 years as a meteorologist. I'm sure climate models have also had significant improvements in the last 20 years and will continue to improve in the future.

Here is additional information from Dr. Richard Alley, Evan Pugh Professor of Geosciences at Penn State, talking about climate proxy.

Question: Dr. Alley, is any one climate proxy more accurate than the others? Does any provide more information than the others?

Dr. Alley's Answer: Consider the width of a tree ring. It records how "happy" a tree is by how much the tree grew. Go to a very dry place, and a "happy" tree is one getting rain, so the tree rings are rain gauges. Go to a very cold place, and a happy tree is a warm one, so the tree rings are thermometers. But, the tree will also notice if it is being eaten by beetles, or shaded by neighbors, or other things. So the history of thickness of tree rings from one tree is unlikely to be a very good climate record. But, use a lot of trees, and you start to average over the changes in beetles and neighboring trees, and to see the climate signal. With enough trees, and enough cleverness, you start to learn about temperature and rainfall, over large areas.

Consider the isotopic composition of nitrogen and argon in ice-core bubbles. When snow falls on an ice sheet, the weight of the new snow squeezes the old snow until bubbles are pinched off, trapping air samples. Usually, the snow gets a couple of hundred feet deep, so the bubbles are being trapped way down there. The spaces in the snow are interconnected from the surface down to a couple of hundred feet, but the spaces are small enough that the wind doesn't mix the air, which instead mixes by diffusive processes.

If you warm or cool the surface, it takes a century or so for the temperature to change down where the bubbles are trapped (it takes a short while to burn the thin skin on your finger if you touch a hot burner, much longer to cook a hamburger, and much much much longer to cook a turkey; roughly, make something twice as big and heating it takes four times as long, so the couple of hundred feet to the bubble-trapping depth does take a century or so).

During that century, the temperature at the top and bottom of the snow will be different. When communicating gases not mixed by the wind have a temperature difference imposed, the gases separate (by a TINY amount) with the heavier ones on the cold end, in a process known as thermal diffusion, which is very well understood by physicists. This makes the trapped gases slightly different from the free atmosphere. If one measures characteristics (such as the isotopic composition of nitrogen and argon) that cannot change rapidly in the atmosphere (because there is so much nitrogen and argon up there, and such small gains and losses), then you can learn the deviations, and thus the temperature differences across the snow, and thus the history of temperature change at the surface. This is almost entirely a history of temperature change in the near-surface (there is a "tweak" because the gases also separate a tiny bit under gravity, and the thickness of the snow hence the gravitational effect may change a bit, but by measuring argon and nitrogen isotopes, the temperature and gravity effects can be separated because they affect nitrogen and argon differently. Then, because the gravity depends on the snow thickness which depends on temperature and snowfall rate, you can learn something about snowfall, too.). This is a much easier thermometer than a tree ring, because the gases don't worry about neighboring trees or beetles (which are notably absent on the ice sheets). But, we don't happen to have an ice sheet in Kansas, so we have to use tree rings or something else there rather than ice-core gases.

In short, nature gives us lots of indicators, the indicators are not as easy as going out and reading a thermometer, but we can read the indicators with a bit of effort and care.

NewScientist recently ran a fascinating (if you're a human) and tragic (if you're a turtle) article on how global warming may be causing an imbalance between male and female loggerhead turtles.

According to the article, "The gender of marine turtle offspring is determined by the temperature at which the eggs are incubated: high temperatures lead to a higher proportion of females." Should temperatures rise by two degrees C, male offspring would vanish from the beaches of Florida, which is one of the most important loggerhead turtle nesting grounds in the United States.

While the study the article draws from may make the world's turtle researchers apoplectic and spell doom for Florida's booming loggerhead turtle singles scene, keep in mind that two degrees C is a pretty significant jump in temperatures.

As I mentioned last week, Dr. Richard Alley, Evan Pugh Professor of Geosciences at Penn State, has taken the time to answer some of my questions about paleoclimatology. In today's post, he talks more specifically about the information that can be gleaned from an ice core.

Question: Specifically related to ice cores, can you explain what information is captured in glacial ice and how you "read" it? How can you tell the difference between a cold year and a year with higher than average precipitation, for instance?

Dr. Alley's Answer: Temperature, I explained earlier (Trees and Ice are Links to Past Climate).

Another we use (a "fuzzy" one--doesn't reveal short-lived temperature changes a long time ago, but is reliable) is the physical temperature of the ice. If you throw a frozen turkey in the oven, turn on the heat and then leave, and your significant other comes home and wants to know how long the turkey has been in but doesn't have your cell phone number, why, drill a hole in the turkey, measure the temperature, and the colder the inside, the shorter time the turkey has been cooking. The Greenland ice sheet a mile down is colder than the surface is, and is colder than the bedrock two miles down, because the ice is still warming from the cold of the ice age, and we can estimate how cold the ice age was in central Greenland from this.

Another is related to the isotopic composition of the water in the ice. If you have a bunch of water molecules, a few of them will have an extra neutron or two ("heavy water"). The heavier water is still water, but just a tad heavy. The heavier stuff rains or snows out of a cloud first. As an air mass moves over an ice sheet and cools, the heavy falls out, so the remaining vapor comes closer and closer to being all "light", so the next rain or snow becomes more and more "all light". The colder the air mass, the lighter the isotopic makeup of the rain or snow. So, the isotopic history in an ice core is a temperature history. If you look at isotopes, and isotopes of gases, and borehole temperatures, you can start to get a reliable history of temperature at the site.

In favorable ice cores, we date by counting annual layers (summer snow and winter snow look different, are isotopically different, chemically different, electrically different, etc.). We check as far back as we can using known time markers (find the fallout from historically dated volcanic eruptions, or from atomic-bomb explosions), and it works really well. We have several people count several things several times, try really hard not to "cheat" by checking on the answers of others, and then compare our ages to those for correlative climate events in other records (tree rings, etc. from elsewhere). The thickness of an annual layer (after a correction for thinning from compaction under weight of snow above and from ice flow) gives the snow accumulation rate. Changes in "dirtiness" of ice (how much dust) either represent changes in the dust delivery, or in the delivery of water to dilute the dust; know the accumulation rate, and you have the dilution.

A refrozen-meltwater layer shows it was warm. Fallout of odd nuclides made by cosmic rays in the atmosphere tell how many cosmic rays were getting in (and because the magnetic field and the sun's activity help protect us from cosmic rays, tell about the magnetic field and the sun's activity). One can find micrometeorites, pollen, sea salt, etc. and learn about those. And, the trapped bubbles are our only reliable samples of old air and the greenhouse gases in that old air. So, there is plenty to learn.

Here is our final question-and-answer session with Dr. Richard Alley, Evan Pugh Professor of Geosciences at Penn State. To review, Dr. Alley studies paleoclimates from ice cores and is one of the authors of the IPCC's 4th Assessment.

I'd like to say thank to you to Dr. Alley for sharing so much information with the blog over the last couple of weeks.

Question: Dr. Alley, how can you tell what forcings were involved with past climate changes?

Dr. Alley's Answer: One can use strength of magnetization of lava flows and sediments to learn about the strength of the magnetic field, and then the changes in cosmic-ray-produced things not explained by the magnetic field are probably changes in the sun (we don't think the total cosmic ray flux changes much). There are small changes in the sun recorded, and small changes in climate going along, with a behavior that matches what we expect. The large changes in magnetic field that have happened don't seem to have had an effect on climate, so that doesn't seem to be an important forcing. There is little evidence of changes in micrometeorites/space dust (except for the occasional giant meteorite such as the one way back that killed the dinosaurs), so space dust doesn't seem important. Volcanoes block the sun and bring cold--a degree or two for a year or two--this is well-recorded, but isn't "organized"--one eruption doesn't trigger another, so the volcanoes mostly make "noise". The very skinny version is that climate has been mostly controlled by sun (with small changes in total brightness giving small climate changes), and by greenhouse gases (mostly CO2). In addition, features of Earth's orbit (which move the sunshine around over the planet over tens of thousands of years--more in the north or the south, or more at the equator or the poles) have paced ice ages, in part by affecting CO2. Over long times, drifting continents affect where ocean currents go and other such things, which matter to climate.

Question: What degree of confidence do paleoclimatologists have in the climate reconstructions? Does it diminish farther back in time?

Dr. Alley's Answer: Given the huge range of indicators, the degree of confidence goes from pound-on-the-table/this-is-almost-surely-right to this-is-more-likely-than-not-to-be-right/can't-say-much-more. In general, confidence is better more recently.

Question: Can you compare the current warming in the Arctic with the warming of the 1930s and 1940s? What were the climate forcings that brought on that warming?

Dr. Alley's answer: This is still a topic of research, but the recent paper by Johannessen et al., and other work, give good pointers. The most obvious difference between the earlier warming in the Arctic, and the more recent one, is that the earlier one was mostly restricted to the Arctic, and the more-recent one is almost everywhere. The geographic pattern of the earlier one did not look like that expected for greenhouse gases (which had not risen much yet), and the more recent one does look like the greenhouse-gas pattern. Some worker points to a role for sun and volcanoes in the earlier one (occasionally, by accident, brighter sun and fewer volcanoes happen at the same time), together with a "dynamic" component--perhaps a change in the ocean overturning linked to the Atlantic Meridional Oscillation. The climate is a complex-enough beast that glib answers should be viewed with caution--the IPCC or National Academy statements on global warming are NOT glib, but are cautious and carefully reasoned, and must be.

February sure was cold here in Pennsylvania. The closest reporting station to my house ran 6.8 degrees below normal for the month. And based on the comments I get here, a lot of our resident skeptics live in the north-central and eastern states. So how did February as a whole stack up across the globe? Here's a map of land surface temperatures from NOAA that gives a bit of a global overview:

and blended surface temperature anomalies:

That's a lot of red. According to NOAA, that global temperature anomaly was +0.60°C, 6th warmest February on record.

So how about December-February, known in the northern hemisphere as meteorological winter? Apologies here to my readers in the southern hemisphere. I know it's summer where you are. Here are the same maps from above, only for a Dec-Feb time scale:

For that December-February period, the anomaly is +0.72°C, the warmest on record, 0.07°C warmer than the same period in 2004.

What does this tell us about global warming? Well, of course the answer is virtually nothing because the time scale is simply too small. I post this mostly because of the "Look out the window" comments I've gotten for the last 6 weeks. It's a big world, and what's happening outside any one window doesn't tell us anything, either. You have to look at the big picture.

Speaking of the big picture, I'll wrap up here with one more NOAA graphic. You can draw your own conclusions.

I'd recommend checking out all of NOAA's information on February and December-February if that's something of interest to you.

NOAA scientists have created a new tool to monitor changes in atmospheric carbon dioxide by region and source. The tool, called CarbonTracker uses a larger concentration of observations combined with a sophisticated computer model to create an accurate assessment of greenhouse-gas increases and decreases. The data is still sparse, but should grow as more monitoring sites become available.

"CarbonTracker's potential is enormous," said Pieter Tans, head of the NOAA Earth System Research Lab's Carbon Cycle Greenhouse Gases group, who developed the tool. "We are moving into an era where emissions could have a price tag. If carbon trading, emissions reduction and sequestration schemes become more common around the globe, society will need the ability to compare their relative value. Accurate and objective information on changing atmospheric concentrations will be essential for both research and impact assessments."

CarbonTracker monitors not only carbon dioxide emissions, but also the uptake of carbon dioxide in "sinks" such as oceans and growing forests.

NASA scientists, using satellite observations of aerosol optical thickness, have found that the global aerosol blanket has likely thinned since the 1990s. The images above show the optical thicknesses from 1988-1991 (top) and from 2002-2005 (middle) and the change between the two time periods. What does this mean? In this case, it is a measurement for how much the aerosols are filtering the incoming sunlight. Overall, aerosols are a very complex part of the atmosphere, which can reflect or absorb sunlight.

The researchers say that because aerosols may counterbalance greenhouse gas warming, the decline in aerosol dimming power may have made the greenhouse warming trend more evident during the past decade.

Elliot Abrams's blog entry How might April fool us? features a discussion some of the latest global warming science, straight from Science magazine. The two articles are Ice Sheet Stability and Sea-Level Rise and Atmospheric Science: CO₂ Is Not the Only Gas (which I believe may be the winner of a "worst headline" competition). You must be a subscriber to read these articles in Science. Elliot plans on contributing this kind of information on a regular basis.

Jesse Ferrell and I had some sort of strange psychic moment yesterday. Seems we both decided at the same time to watch the British TV documentary The Great Global Warming Swindle, which aired in Britain back on March 8. Jesse wrote about it in the AccuWeather.com Community Blog.

Only a trailer for the program is available at the Channel 4 site. The whole thing has popped up here and there - the links appear to be ephemeral, but you can try searching for it on Google Video or YouTube.

So what was my opinion? It was interesting. Some of the information presented was familiar to me, some of it was new. Not surprisingly, it prompted quick and resounding condemnation from the other side - and in one case from one of the scientists who appeared in the program. Carl Wunsch, a professor of physical oceanography at MIT, believes the filmmakers mislead him about their goals and used his words out of context. Dr. Wunsch's response to the film is very thoughtful and worth reading. UK publication The Independent documents some of the questionable evidence used in the film. A couple of the climate modelers who run RealClimate didn't pull any punches with their comments. I'd be interested to know the reactions of any of the other scientists featured in the program to the finished product.

I don't think all the questions regarding climate change have been answered, but I don't think dueling documentaries are going to answer any of those questions and I don't know that they merit much attention. At the end of the day, it comes down to the science, not who makes the most persuasive argument.

Whew....I started my forecasting shift before the sun rose this morning, and it's now mid-afternoon. Y'all have a good day - I'm hitting the highway. I've got some ideas for the blog for tomorrow - hopefully they'll flow more smoothly than this entry.

The second of 4 IPCC reports is due out tomorrow morning, but apparently delegates are struggling with the wording of the 21-page Summary for Policymakers and some are worried they will miss the deadline.

The full report - which was made available to the Associated Press last week, but which us regular people have to wait for, is 1572 pages. The report describes the effects of global warming, including "key vulnerabilities" charts which some have describes as a "highway to extinction."

Longtime readers of this blog may remember a post from mid-December about trees, and the importance of their physical location in terms of whether they slowed global warming or enhanced it. I had a little feeling of deja vu this morning when I opened an article published yesterday at Scientific American.com. This new study, published in Proceedings of the National Academy of Sciences, found similar results.

Forests in tropical regions serve as carbon sinks, forests in the mid-latitudes are nearly carbon-neutral, and boreal forests, the zone pictured here in dark green in an image from NASA, actually contribute to global warming.

How is that possible? It's mostly due to albedo, that measure of the reflectivity of the Earth's surface. Tropical trees, growing in very wet soil, produce by a process called evotranspiration a layer of clouds which reflect sunlight. That reduction in solar input combined with the carbon storage in the trees has an overall net cooling effect on the globe. Compare that to the boreal region - primarily coniferous trees in an area covered by snow for a significant portion of the year. The soil is dry, so the trees produce little moisture and few clouds via evotranspiration, and the trees absorb more energy than snow-covered land would reflect.

The study was done using a model which captured all three of these forest characteristics - carbon storage, reflectivity and evotranspiration. In the framework of the model, researchers were able to see what would happen if the entire globe was deforested. The research has value because it shows where reforestation has the most value in mitigating greenhouse gases and reducing global warming.

Trees of course, have importance far beyond their role as carbon sinks. Sustaining forests helps to sustain the world's biodiversity. Making decisions on forestry based solely on global warming isn't good policy for the world.

I found an interesting entry over at Roger Pielke Sr.'s Climate Science blog on the soon-to-be-released correction of Lyman, et al, Recent cooling of the upper ocean, published in the Journal Geophysical Research Letters. In the correction, the cooling will be shown to have been removed, however, it will be shown that the warming of the 1990s-2002 has not persisted.

I've written a lot about the debate surrounding the effect global warming will have on hurricane activity, particularly in the Atlantic. A new study from scientists at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami and NOAA's Geophysical Fluid Dynamics Laboratory (GFDL), scheduled to be published today in Geophysical Research Letters concludes increasing wind shear could decrease Atlantic Hurricane activity.

Vertical wind shear is one of the most significant inhibitors of tropical cyclone development, and can quickly weaken an already developed tropical system. Using 18 different computer models, researchers found an increase in wind shear due to a slowing of the Pacific Walker Circulation.

Chris Landsea, Chief Science and Operations Officer at the National Hurricane Center, has weighed in with his opinion of this new research at Prometheus.

Nigel Weiss, Emeritus Professor in Mathematical Astrophysics at the University of Cambridge, spoke last Wednesday at the Royal Astronomical Society's National Astronomy Meeting. He described how solar activity was important in past climate change, but current global warming is driven by human activity.

The variations in global temperature driven by solar variation tend to be on the order of 0.1-0.3 degrees Celsius, while in the past 100 years, global temperatures have increased by almost 1 degree Celsius. We are currently in a period of high solar activity, which would correspond to some warming. At some point that activity will diminish, though scientists have no way to predict exactly when that will happen or how intense the upcoming minima will be.

Will the upcoming minima counterbalance global warming? Don't count on it, says Professor Weiss:

"Although solar activity has an effect on the climate, these changes are small compared to those associated with global warming," he said. "Any global cooling associated with a fall in solar activity would not significantly affect the global warming caused by greenhouse gases."

It seems like there have been a lot of questions raised here about how much carbon humans are adding to the atmosphere and why it matters. We've got to take a look at the carbon cycle to try to understand these things. The carbon cycle is extremely complex, and this will in no way be an exhaustive reference on the subject.

Carbon is the foundational element of all organic substances on Earth, from fossil fuels to family pets. Carbon moves through the Earth's systems in several different ways. In geologic time, weathering and erosion wash carbon-containing compounds into the ocean. Eventually they settle to the bottom where they are eventually drawn into the Earth's mantle through a process called subduction. That carbon is eventually reintroduced into the atmosphere as carbon dioxide during volcanic eruptions.

On a shorter time scale, plants use solar energy and the process of photosynthesis to remove carbon dioxide from the air and produce carbohydrates. Plants and animals return that CO₂ to the atmosphere through respiration and also through decomposition. In the ocean, carbon dioxide processed by phytoplankton gets processed into calcium carbonate shells by some organisms. Those shells settle to the bottom of the ocean and form sediment. Carbon dioxide also enters sea water through simple diffusion at the surface, and some of that gets mixed into the deep ocean.

Fire consumes biomass material and releases carbon dioxide to the atmosphere.

Carbon dioxide in the atmosphere has diminished over several billion years of geologic history. Some of that carbon dioxide was locked into fossil fuels and sedimentary rock.

All of these things happen without human intervention. So how are we impacting the carbon cycle? When we burn fossil fuels, we're releasing carbon into the atmosphere at a rate of 5.5-6 gigatons of carbon per year (giga=1 billion). In addition, land use changes such as deforestation add about 1.6 GtC per year to the atmosphere. Some of that human-produced carbon is captured by the oceans and other carbon sinks, but the net result is an addition of 3-4 GtC per year added to the atmosphere, which is why a graph of carbon dioxide concentration looks like this:

Elliot Abrams has a new post at the Global Perspective blog which summarizes some current science and science policy issues. Since that blog is not comment-capable, feel free to post your comments and questions to Elliot here.

Elliot will be joining Dr. Joe Sobel as a regular part of the Global Perspective blog, a section of AccuWeather.com's Global Warming Center.

Quite frequently, I've gotten comments here from people who bring up warming on other planets as an argument that what's going on here on Earth is just part of a natural cycle. Russian astronomer Habibullo Abdusamatov agrees, according to National Geographic News. I've commented on Abdusamatov's ideas on Earth's climate here before. The Earth's climate is complex enough for me, I don't have much time for learning about what is going on in other parts of the solar system. Just the basic fundamentals of what can affect climate, shape of orbit, length of year, angle of axis - all these things that are pretty much basic parts of our understanding of our climate - how many of us can describe any of those things for another planet? I know I cannot.

The April 5 issue of Nature featured an article titled Global warming and climate forcing by recent albedo changes on Mars (abstract available free, full article is subscription or pay only). The article described how dust storms on the planet's surface change the albedo, or reflectivity, of the surface. In the 20-year period between the Viking mission in the 1970s and the Mars Global Surveyor (MGS) mission around 2000, imagery shows that many areas of the planet darkened. This darkening reduced the reflectivity and brought the potential for a ~0.65 K rise in temperature over that 20 year period. A Kelvin degree is the same size as a degree Celsius, the scale starts at absolute zero, a hypothetical temperature where all molecular movement stops. That darkening explains most, though not all, of the loss of CO2 ice in the southern polar ice cap.

One thing that was very clear from the article is that many Martian climate processes are not well understood. In my opinion, making claims about Earth's climate based on what is going on in other parts of the solar system is treading on thin ice.

A new discovery from NASA scientists at the Goddard Space Flight Center reveals we still have a lot to learn about our atmosphere. Previously unknown "in-between" particles in the air around clouds add a new layer of complexity to modeling weather and climate. Scientists believe what they're seeing is a transitional zone where clouds are forming or dying away. This zone can take up as much as 60 percent of the atmosphere previously labeled as cloud-free.

What is unknown is what effect these particles have - water vapor is a potent greenhouse gas which traps the sun's energy, while clouds reflect incoming solar radiation.

"The effects of this zone are not included in most computer models that estimate the impact of aerosols on climate," said lead author Ilan Koren of the Weizmann Institute of Science, in Israel. "This could be one of the reasons why current measurements of this effect don't match our model estimates."

RealClimate.org had an interesting entry yesterday on James Hansen's 1988 congressional testimony and the model data he presented then. Dr. Hansen presented three potential scenarios with different conditions - exponential growth in climate forcings, linear increase in forcings and linear increase until 2000, with near constant forcing beyond that time. Hansen said at the time that the middle scenario was the "most plausible."

I'm not going to rehash all of the information in the RealClimate entry here, readers should follow the link and look at the information for themselves. Hansen's "most plausible" scenario is looking pretty good.

The Southern Ocean - the largest sink for atmospheric carbon in the world - is losing its ability to absorb carbon dioxide, according to researchers. The scientists, led by Corinne Le Quere of Germany's Max Planck Institute, blame increasing winds over the ocean surface - which they also tie to human-produced climate change for the reduction in the ocean's ability to sequester carbon.

The winds, the scientists say, are increasing due to the depletion in upper-atmosphere ozone over the Southern Ocean, which has produced large temperature changes throughout the atmosphere, and the uneven nature of global warming, which has also resulted in tighter temperature gradients across the region. The winds mix natural carbon which is normally held in deep waters to the surface, which reduces the surface water's capacity to absorb additional carbon.

"This is the first time that we've been able to say that climate change itself is responsible for the saturation of the Southern Ocean sink," Le Quere said. "This is serious. All climate models predict that this kind of 'feedback' will continue and intensify during this century."

The full study can be downloaded at sciencexpress.org, a subscription-only site.

Mesoscale eddies, intermittent ocean currents 100-200 kilometers wide, stir up carbon-rich detritus from the ocean bottom and spread it on the surface where plankton feed or grow. Plankton are tiny plants and animals which compose the foundation of the ocean's food chain. It was believed that large "blooms" of plankton would absorb carbon from the atmosphere, but new research indicates otherwise. In fact, these circumstances may constitute a net source of greenhouse gas into the atmosphere. Scientists say the eddies are poorly understood and more research needs to be done.

Understanding the Earth's energy budget - the balance between incoming solar energy and the energy the Earth gives off - is one of the keys to understanding climate change. Without a complete picture of the Earth's energy budget, it's impossible to understand the natural and human-induced influence on climate, according to University of Michigan geophysicist Shaopeng Huang.

A failed experiment conducted by Apollo 15 astronauts resulted in NASA's acquisition of 41 months of surface temperature data from the moon. The temperature on the moon's near side is controlled by solar radiation during the day and by radiation from the Earth at night. This gives a clear picture of the Earth's energy budget unencumbered by complications associated with the atmosphere and biosphere.

Huang would like to see a network of monitoring stations set up on the moon for the study of climate change on Earth.

The journal Nature recently added a new climate change blog, Climate Feedback. to their web site. I wanted to point people here to this site as another good reference for news and scientific information on climate change.

In this week's edition of Headline: Earth, Katie Fehlinger's climate change headlines included a reference to a new study released by NASA and the Columbia University Earth Insitute. This study, lead by Dr. James Hansen, concludes that the Earth's climate is approaching a dangerous tipping point. A tipping point is a threshold at which moderate temperature change is dramatically amplified by feedback mechanisms. One of my first entries on this blog talked about the potential positive feedback produced by the loss of snow and ice cover in the Arctic.

This study concludes that increased warming of only about 1° C (1.8° F) above 2000 levels is likely to be dangerous. "According to study co-author Makiko Sato of Columbia's Earth Institute, 'the temperature limit implies that CO₂ exceeding 450 ppm is almost surely dangerous, and the ceiling may be even lower.'"

Dr. Hansen has been one of the loudest and most urgent voices on anthropogenic global warming for the better part of two decades.

A new study by scientists from UC Irvine have determined that dirty snow can explain one-third or more of Arctic warming mostly associated with greenhouse gases. The snow becomes dirty when soot from tailpipes, smokestacks and forest fires gets into the atmosphere and then falls back to the ground. The sooty snow is dirtier and darker than snow without soot, meaning it absorbs more sunlight. Pure white snow is more efficient at reflecting the sun's light and heat energy.

The scientists believe that the sooty snow can explain up to 19 percent of total global warming in the last 200 years, and at least one third (and perhaps as much as 94 percent) of warming in the Arctic.

The majority of the soot comes from industry and fuel consumption, which means that although this is not greenhouse gas warming, it is still anthropogenic warming. The researchers say that limiting industrial soot emissions and using cleaner-burning fuels would brighten snow and have an immediate impact on the Arctic.

A recent edition of NewScientist magazine listed 26 of the most common climate myths and misconceptions (Climate Change; A Guide for the Perplexed).

The article takes on a wide variety of myths, including human CO2 emissions are too small to matter and the oceans are cooling. It also includes my personal favorite, it's too cold where I live--a little warming will be great, since that one allows for the possibility of a personal belief in global warming and its potential disasters, but as long as I'm more comfortable, it's fine with me!

I'm certainly not saying that this article has all of the answers, but it's certainly an article that both skeptics and believers of AGW might find interesting.

I know this May data from NOAA was released about 10 days ago, but I figured not everyone saw it. Since this blog is about "global" warming (as opposed to just the United States), I will just hit on the global highlights......

1. Combined land and ocean surface temperatures for May were the fourth warmest on record. Almost a 1 degree F above the 20th century mean. Keep in mind, this is only for a 128-year period. Not a lot when it comes to climate change.

2. Combined land and ocean surface temperatures for the Jan-May period tied 1998 as the warmest.

3. Just looking at the global land temperatures, the Jan-May, Mar-May, and May period was the warmest on record.

4. Just looking at the ocean surface temperatures for May it was the ninth warmest on record, but near or slightly cooler than normal near the equator, which is partly due to the trend toward a La Nina episode.

5. Global surface temperatures have increased at a rate of 0.11 degrees F per decade, but that rate has been 3X larger since 1976. The greatest increases being in the high latitudes of the northern hemisphere.

Note........

I will be on vacation for a week starting today (Monday), but the global warming debate will continue as normal. I will post new topics to discuss from time to time, and the gaps will be filled in by guest moderators. Brett.

Professor R Timothy Patterson of the Ottawa-Carleton Geoscience Centre stated in an article from The Financial Post on Canada.com that his research into the mud layers on the bottom of certain fjords in British Columbia reveals that solar output is a stronger player in climate change than CO2 and that global cooling is on the way. Patterson found a direct correlation between the changes in mud layers over 5000 years and the solar cycle.

The article states that solar scientists predict that by the year 2020 the sun will be going into its weakest Schwabe Solar Sunspot Cycle in the past two centuries, leading to global cooling.

Make sure to check out the sunspot graph in the middle of the article. Click on it to make it larger.

Even though the above worm may look innocent enough (certainly slimy enough!), a German study has found that worms produce greenhouse gases that are 290 times more potent than carbon dioxide. The Materials Recycling Network (UK site) has more information in a recent post titled Worms are killing the planet, says top researcher.

Maybe we should start talking about WGW (Worm-opogenic Global Warming) instead of AGW (Anthropogenic Global Warming)!

A recent article in Times Online (out of the UK) talks about climate predictions that have already occurred (Ten Predictions About Climate Change That Have Come True).

I'm neither endorsing or condemning the information by pointing out that the author, Tim Flannery, of the article has a book to sale.

A newly released study says that there is no link between solar activity and Global Warming.

The lead author of the report, Mike Lockwood, of the Rutherford Appleton Laboratory states "The temperature record is simply not consistent with any of the solar forcings that people are talking about." One of the ways that the sun affects the climate is through clouds. The sun's magnetic field shields the Earth from cosmic rays. The rays help form clouds that reflect the sun's energy back into space resulting in a cooler climate. According to Lockwood, in the article posted in the Guardian Unlimited, the sun's magnetic field has decreased since 1985, and global temperatures have risen at an accelerating rate. If the sun's magnetic field is high there should be a fall off in cosmic rays, fewer clouds and more warming on earth. Lockwood says that the study was "another nail" in the coffin of the notion that solar activity is responsible for Global Warming.

Photo courtesy of Wikipedia

A recent study is linking ozone smog with global warming.

According to the article "Smog to Accelerate Global Warming" which I found on Physorg.com, lead researcher Stephen Sitch of the Hadley Centre in Great Britain states that ozone smog will accelerate global warming by damaging carbon emission absorbing plants and trees. Ground-level Ozone, which is a man-made pollutant made up of fossil fuel gases and sunlight has been recently found to have a negative effect on vegetation.

On a side note....I keep reading stories about British Prime Minister Brown blaming the recent floods across southwestern England on climate change. I realize some of the flooding was the worst in 60 years, and that is no doubt a serious situation, but is he justified to quickly link the two?

Joseph Fourier, Image Courtesy of Wikipedia

I know that the topic of Carbon Dioxide and a warming climate has been a major topic of discussion in recent years, but I didn't know--at least until I read this article (A 175-Year-Old Puzzle)--that the relationship between warming and CO2 has been a discussion for more than the past 175 years. The first known discussion of the topic was in an essay by a French mathematician and physicist, Joseph Fourier, that was written in 1827.

Over the weekend, an interesting Associated Press article that I read on MSNBC (Researchers Blame Rise in Storms on Warming) includes both information on research that indicates human-induced warming is responsible for an increasing number of hurricanes and a response by National Hurricane Center's Chris Landsea, who calls the study "sloppy science."

A pair of U.S. scientists has used mathematics to measure the effect of natural solar variation on climate change.

Charles Camp and Ka Kit Tung of the University of Washington's Applied Mathematics Department said that in order to accurately assess the effects from man-made sources on the earth's climate, scientists must first be able to quantify the contribution of natural variation in solar irradiance to temperature changes, according to a small article from Earthtimes.org

The two scientists determined that times of high solar activity are on average 0.2 degrees celsius warmer than periods of low solar activity as they compared the earth's surface temperature measurements between years of solar maximum and years of solar minimum. They also found that the warming was amplified in the polar regions.

The authors state that their findings are believed to be the first to document a statistically significant globally coherent temperature response to the solar cycle.

I personally find it hard to believe that this type of statistical study has not already been done. It does not seem to complicated. Brett.

Image courtesy of Wikipedia

I came across this article in Nature titled "Climate Catastrophe". In addition to the content of the study, what else caught my eye was the fact that authors of the study, Alan Robock and colleagues were from Rutgers University, which is my alma mater.

In the study, Robock and others concluded that the smoke generated by even a "small" nuclear war would lead to deadly and widespread climatic disruption, causing a much higher mortality than the bombs themselves.

The research team ran two simulations, using a new global climate model for the first time that reaches up into the mesosphere. One simulation assumed a war that unleashed 20,000 weapons, while the other simulation assumed a third of that total.

The study finds that there would indeed be a true "nuclear winter". Soot would persist in the atmosphere for over a decade, resulting in global cooling by as much as 7 degrees celsius (12 F). Rainfall would be halved, leading to global famine. The second simulation showed that the effects from a limited war would be less severe, but would last just as long as the full-scale.

In regards to my August 23rd post titled "Nuclear War and Climate Change" we received a response from Alan Robock, who was the lead researcher on the subject of this post.
He was kind enough to provide a more detailed link to his study titled "New studies of climatic consequences of nuclear conflicts".

Here is his response........

With regard to my recent work, I have posted all the papers at:

http://climate.envsci.rutgers.edu/nuclear/

It would be great for you to actually read them before posting comments. But I can summarize the bottom line:

A nuclear war between India and Pakistan using 100 Hiroshima-size weapons could kill more than 20,000,000 people and produce climate change unprecedented in recorded human history, drastically affecting agriculture for many millions of others. It clearly is not a solution to global warming.

The US and Russia still have enough weapons to produce a full nuclear winter, leading to starvation of billions.

Nuclear disarmament is the only way to remove this threat to the planet, and the US and Russia should begin immediately, to set an example for the rest of the world. Nuclear weapons can never be used.

In this past Sunday's Parade section of the newspaper I read a small article which links coal-mine fires in China and India to global warming. Sorry no links here, you will have to dig it out of the recycle bin.

According to the article, coal-mine fires could be a huge culprit in global warming. In the country of China, up to 200 million tons of coal go up in flames each year, which could be equal to America's total CO2 emissions from gasoline.

Some experts (though you are not told who) are wondering if controlling mine fires in Asia might be a key to reducing global warming. An economist, Diana Furchtgott-Roth argues that controlling the fires would be more efficient than offsets like planting trees or cleaning the ocean.

How do you control the fires? One remedy which is being developed in the U.S. is nitrogen-laced foam. It recently put a fire out in a West Virginia mine. Using this supposedly successful foam in China and India could greatly reduce the damage caused by these long-burning fires says the author.

Last week, the DailyTech reported that a new survey, which is about to be published in the Journal of Energy and Environment finds that less than 50% of the scientific papers written about climate change since 2004 have endorsed the idea that man's activies are causing global warming. The link to the DailyTech story is gone already, but you can see the story here from Newsbusters.

The survey was performed by a medical researcher named Dr. Klaus-Martin Schulte, who used the same search terms as the original survey done by Naomi Oreskes. The new survey by Schulte supposedly indicated a major shift in the scientific community away from IPCC consensus in regards to man-made global warming. That may be true if we just compare the the two studies. But, there was another similar study done in 2005 by Professor Benny Peiser, who is a climate change skeptic, that seems to have been forgotten, even though it had some errors. For fun, let's compare all three surveys........

Naomi Oreskes study.

Oreskes analyzed 928 abstracts from 1993-2003 from the ISI database using the search keywords "global climate change".

75% accepted consensus view, either explicitly or implicitly.
25% took no position (neutral)
0% disagreed with consensus

Peiser study.

Peiser analyzed all abstracts for the same period 1993-2003 and came up with these results......

~30% accepted consensus view, <1% explicitly and 29% implicity.
3% disagreed or rejected consensus

Peiser's survey was eventually rejected by the editors of Science. Dr, Peiser recently conceded that his study did contain some errors and he no longer doubts that " an overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact, but he contends that the majority consensus is far from unanimous.

The recent Schulte survey (2004-2007) total 528 papers.

45% accepted consensus view, either explicit or implicit.
48% neutral
6% disagreed or rejected consensus

I have no way of confirming whether or not the latest survey results by Schulte show a clear trend away from consensus. Here is why.....

--I am sure that when the Oreskes survey came out the AGW skeptics and deniers were disregarding the results, and maybe rightfully so, but now that there is a new study out, they are more than willing to compare the studies, using the Oreskes results as a base and showing the dramatic change in opinion from the scientific field.

--If you use Peiser's results as a base, then the trend to the the Schulte study shows an increase in supporters of consensus, but also an increase in those who rejected consensus from 3% to 6%.

--What is Dr. Schulte and what is the Journal of Energy and Environment? Not much info I could find. I noticed most of the books that they sell on their web site are skeptical or deny AGW which is interesting.

--I would love to see a sampling of these journals. I suspect a number of these journals may briefly touch on the idea of man-made global warming, but I suspect their main focus could be on something else, perhaps pharmacuticals and medicine.

--The results of all three studies still suggest that there is still a very small percentage of scientific papers that reject consensus, but there is a growing number that are not totally buying into it and are beginning to question it.

--I think there needs to be a better way of finding out this information. How about taking a survey of as many earth and atmospheric scientists across the globe as you can. A few simple questions and a yes, no or not sure answer. #2 pencil included.

According to a US Environmental Agency, dams across the world are contributing millions of tonnes of greenhouse gases (mostly methane) to the atmosphere. How is that? When water flow is greatly slowed or stopped behind the dam, dead fish and vegetation quickly rot, giving off methane, which is a greenhouse gas 25 times stronger than CO2.

"Often its accepted that hydropower is a climate friendly technology, but in fact probably all reservoirs around the world emit greenhouse gases and some of them, especially some of the ones in the tropics, emit very high quantities of greenhouse gases even comparable to, in some cases even much worse than fossil fuels like coal and gas." said Patrick McCully, executive director of the International Rivers Network in an article from News.com.au

McCully said global estimates blamed dams for about a third of all methane emissions worldwide! He also believes that greater energy efficiency is needed to be researched to overcome the problem by increasing technology that could produce energy from the methane from dams. We saw a similar example of trapping methane and using it for energy by the Lehigh Valley sewer authorities of Pennsylvania from Katie Fehlinger's last video.

The increase in atmospheric carbon dioxide in the coming decades will cause birch trees to drive out the aspens in northern forests, according to a University of Michigan researcher and his colleagues.

In the experiment, which is previewed here at ScienceDaily, University of Michigan microbial ecologist Donald Zak and colleagues have been pumping extra carbon dioxide into a large plot of mixed tree canopies since 1997 in order to simulate the predicted atmospheric conditions during the latter part of this century. Three different types of trees that are common in northern forests were subject to the experiment and those included were aspen, birch and the sugar maple tree.

The researchers found that the CO2 bathed trees grew 45% faster, but in order to sustain this increase in growth rate the trees had to grow more roots and be able to forage more successfully for nitrogen. The team found that the birches were better at foraging than the aspens. The birch trees increased recent nitogen aquisition by 68% versus 19% by the aspens.

The study shows that in places such as Michigan, the increase in carbon dioxide in decades to come could alter the abundance of birch and aspen by favoring birch.

BTW, speaking of birch trees, I personally love trees and plant them when I can, but I must say the birch tree that I planted in my front yard is the biggest magnet for pests through the summer. You really have to constantly spray these trees to keep them looking decent and healthy. That tree is the first and the last birch I will plant, just too much work. A great shade tree which does not attract the leaf eating buggers is the Norway Maple.

There has been a lot of talk recently about worldwide sea-surface temperatures and the anomalies. I figured I would post the latest Reynolds sea-surface temperature anomaly of the world, courtesy of the National Climatic Data Center. For comparison, I also have included the early September analysis from 2003,2004,2005 and 2006. One thing that is
fairly obvious in looking at these graphs is that a clear majority of the warm anomalies continue to be located in the northern hemisphere. Also, note the cooler anomalies (blues) extending westward from South America into the equatorial Pacific on the latest map which is showing the growing La Nina phase. Last year at this time, there was a trend toward a weak El Nino (warmer anomalies along the equatorial Pacific) which some believe was responsible for shutting down the expected active Atlantic hurricane season. Looking at 2005, which was the year with a record amount of named storms in the Atlantic Basin you can see a significant warm anomaly between the Atlantic and Caribbean.

The latest from Sept 5th, 2007

Sept 2006

Sept 2005

Sept 2004

Sept 2003

A recent study from the Lawrence Livermore National Laboratory in California states that observations and climate model results confirm that human-induced warming of the planet is having a pronounced effect on the atmosphere's total moisture content.

"When you heat the planet, you increase the ability of the atmosphere to hold moisture," said Benjamin Santer, the lead author of the study from the Lawrence Livermore National Laboratory's Program for Climate Modeling and Intercomparison. According to Santer, the atmospheric water vapor content has increased by 0.41 kilograms per square meter since 1988 and the natural variablity in climate just cannot explain this moisture change. "The most plausible explanation is that it is due to the human-caused increase in greenhouse gases," said Santer. "More water vapor, which is itself, a greenhouse gas, amplifies the warming effect of increased atmospheric levels of CO2. This is also called 'positive feedback'."

According to the article, basic theory, observations and climate model results all show that the increase in water vapor is roughly 6 to 7.5% per degree celsius warming of the lower atmosphere.

The Lawrence Livermore National Laboratory is managed by the University of California for the National Nuclear Security Administration within the U.S. Department of Energy. The study was recently published in the online version of the Proceedings of the National Academy of Sciences.

The National Snow and Ice Data Center (NSIDC) now believes that the new record for minimum sea ice coverage in the northern hemisphere was indeed reached on September 16th, 2007 as the summer melt season has appeared to have ended, and sea ice loss has either stopped, or reversed due to the change in season. Also, as of September 20th, the Northwest Passage is still open, but is starting to refreeze.

The sea ice extent in the northern hemisphere on September 16th, 2007 covered 1.59 million square miles (4.13 million sq/km) for a 5-day average. The old record minimum was set just two years ago during September 20-21, 2005 when there was 460,000 square miles (1.19 million sq/km) more sea ice than there was on September 16th, 2007. That difference in sea ice coverage is equal to the size of California and Texas combined, and you can see that here. The sea ice extent by their definition is the total area of all arctic regions where ice covers at least 15% of the ocean surface.

Check out some of the images courtesy of the NSIDC below.....

Arctic Sea Ice extent animation since 1979

"The amount of ice loss this year absolutely stunned us because it just didn't beat all previous records, it completely shattered them," said Colorado University-Boulder senior scientist Mark Serreze of the NSIDC.

A different story in Antarctica.......

The coverage in sea ice in the southern hemisphere, around Antarctica is nearing a record maximum. Patrick Henry has been diligent in keeping us up to date on this story. If you look at the Southern Hemisphere Sea Ice Area Chart, you can see that the latest data point is just shy of 16 million square kilometers. The record maximum is 16.03 million square kilometers. There is still a chance that this record may be broken. Looking at the recent chart, the sea ice extent last year at this time was varying slightly in coverage area from the end of September to mid-October before the steadier fall took place.

The images and data for the southern hemisphere courtesy of the University of Illinois at Urbana-Champaign Polar Research Group.

A newly released study, supported by NASA, reports that snow melt in high-latitude areas of Greenland for 2007 was greater than ever at 150% more than average. The study also noted an overall rise in the melting trend over the entire Greenland ice sheet. The press release states that the amount of snow that has melted this year over Greenland could cover the surface size of the U.S. more than twice.

Marco Tedesco, a research scientist with the Joint Center for Earth Systems Technology, which is managed by NASA's Goddard Space Flight Center and the University of Maryland used satellite data to compare this year's snow melt with the average snow melt for the period 1988-2006. In addition to the snow melt findings this year, Tedesco was able to determine that melting in high level areas has occurred 25-30 days longer this year than the 19-year average.

How about the lower latitude areas of Greenland?

The study also confirmed that the melting Index (determined by multiplying how long melting took place by the area where the increased melting took place) this year in the lower altitude areas of Greenland, though not record breaking, was indeed 30% higher than average, placing 2007 in 5th place behind 2005,2002,1998 and 2004 in that order.

Images courtesy of NASA

The study was published yesterday in the American Geophysical Union's Eos newspaper.

Check out the initialized 00-hour MRF model temperature data across the northern hemisphere polar region from earlier today in degrees celsius. I know it is not that easy to read, but if you look closely you can see a rather large pocket of higher temperatures compared to surrounding areas over the Arctic Ocean north of Siberia and Alaska, which correlates well to the large ice free region that we continue to see on the latest ice cover map at the bottom from the National Snow and Ice Data Center. In this situation, I do believe that the open water is indeed having some amount of warming influence on the surface temperatures in the region. Normally at this time of year, much of this region outlined by the purple line is covered in ice, but there was a record (recorded history) melt this year. The ice covered areas over far northern Canada are much colder. Some of this difference may also be due to the current weather pattern in the arctic, but not all in my opinion. Keep in mind, this is just a one day observation that my fellow meteorologist Jim Andrews pointed out, but we thought it was interesting. Very soon this region will ice over once again has we go through autumn.

Temperature analysis from earlier today in celsius (Alaska is near the center of the map)

Unfortunately, it is hard to compare the two maps as they are on two different scales and looking at different directions.

Image courtesy of the NSIDC

A few of our commentators on this blog found this story earlier today and I thank them.

Anyway, in a news release from NASA Monday, a group of scientists have determined that unusual winds caused the rapid decline (23% loss) in winter perennial ice over the past two years in the northern hemisphere. This drastic reduction is the primary cause of this summer's fastest-ever sea ice retreat in recorded history which has lead to the smallest extent of total Arctic coverage on record.

According to the NASA study, the perennial ice shrunk by an area the size of Texas and California combined between the winter of 2005 and the winter of 2007. What they found was the Arctic Ocean north of Siberia and Alaska was dominated by thinner seasonal ice that melts faster compared to the thicker ice confined to the Arctic Ocean north of Canada. The thinner ice is more easily compressed and responds more quickly to being pushed out of the Arctic by winds.

"Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic," said Son Nghiem of NASA's Jet Propulsion Laboratory and leader of the study. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

What about these unusual wind patterns. Well, the article does not go into that too much, but I must believe some of this is due to changes in the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) which are large atmospheric circulations which have major impacts on the weather in certain parts of the world.

If you look at the two graphics below, you will notice that both the AO and the NAO have been predominately in the positive phase (red) between 1989-1995 and again from 1999 to current. The positive phase of the (AO) typically leads to milder than normal winters over Scandinavia and Siberia, while colder than normal conditions prevail across Greenland. The positive phase of the NAO again leads to colder conditions over Greenland, while much of the eastern U.S. is warmer than normal in general.

A new study co-authored by Nobel Prize winning chemist Paul Crutzen argues that growing some of the most common biofuel crops, including corn bioethanol, releases around two times the amount of the potent greenhouse gas Nitous Oxide (N2O) than earlier studies supported, which, according to the study, would erase any benefits from not using fossil fuels.

"What we are saying is that growing many biofuels is probably of no benefit and in fact is actually making the climate issue worse," said co-author Keith Smith from the University of Edinburgh in Scotland.

According to the article from Chemistry World, some previous estimates had suggested that biofuels could cut greenhouse gas emissions by up to 40 per cent.

Not everyone agrees with the results of this study. Simon Donner, a nitrogen researcher from Princeton University is critical of the study and says there is little evidence to show the nitrous oxide yield from fetilized plants is really as high as 3 to 5%. He believes Crutzen's basic assumption that pre-industrial nitrous oxide emissions are the same as natural nitrous oxide emissions is "probably wrong."

A MODIS satellite composite taken of the Arctic sea ice on September 15th/16th, 2007. You can see the open waters of the Northwest Passage on the lower left of the picture.

Image courtesy of the NSIDC

The average Arctic sea ice extent for the month of September was 1.65 million square miles (4.28 million square kilometers), the lowest September on record (records kept since 1979) which crushed the previous record for the month set back in 2005 by a whopping 23%. At the end of the melt season, the September 2007 sea ice was 39% below the long-term average from 1979 to 2000.

The graph below shows the September ice extent from 1979-2007. An average decrease of 10% per decade.

Image courtesy of the NSIDC

According to the press release from the National Snow and Ice Data Center (NSIDC), one factor that contributed to this fall’s extreme decline was that the ice was entering the melt season in an already weakened state. NSIDC Research Scientist Julienne Stroeve said, "The spring of 2007 started out with less ice than normal, as well as thinner ice. Thinner ice takes less energy to melt than thicker ice, so the stage was set for low levels of sea ice this summer.”

NSIDC Research Scientist Walt Meier also said that an unusual atmospheric pattern, with persistent high pressures over the central Arctic Ocean and lower pressures over Siberia was another factor in the acceleration of ice melt this season. This pattern of warm winds and clearer than normal skies promoted strong melt.

The scientists also noted that the date of lowest sea ice extent continues to be pushed back, resulting in a longer melt season. From 1979 to 2000 the average date of the lowest sea ice extent has been September 12. This year it happened on September 16th. "As the system warms up, spring melt will tend to come earlier and utumn freezing will begin later," said NSIDC Senior Scientist Ted Scambos.

Just as we set a new record in the northern hemisphere for minimum sea ice area in September, the southern hemisphere has officially set a new record for maximum sea ice area. According to the University of Illinois at Urbana-Champaign's Polar Research Group the southern hemisphere sea ice area reached 16.17 million square kilometers, narrowly breaking the old record of 16.03 million square kilometers. The record data goes back to 1979.

Image courtesy of the NSIDC

Keep in mind, even though this is indeed a record, it is not nearly as significant as the minimum record which was just set in the northern hemisphere, in which the sea ice extent was 23% less than the previous record set back in 2005. This new record in the southern hemisphere is not even 1% greater than the old record maximum, and it barely sticks out on the graph of southern hemispheric sea ice area since 1979. Overall, the graph seems to show little variation since 1979. One thing I will say, the maximum sea ice area has ended up higher each year for the past 5 years.

A probe is sent down into a moulin. Image courtesy of NASA

A moulin is the name for a giant hole in a glacier in which millions of gallons of melt water can cascade through to the rocky surface underneath the glacier during the melt season.

Why am I bringing this up now? Well, on a recent trip to Greenland a group of scientists and journalists were alarmed at the size and number of these moulins that they saw on the Greenland ice cap. Some of the moulins in Greenland run on the scale of Niagra Falls and are helping the glaciers to move at three times the rate that they did previously.

Scientists say the acceleration of melting and subsequent speeding up of giant glaciers could be catastrophic in terms of sea level rise and make previous predictions published this year by the Intergovernmental Panel on Climate Change (IPCC) far too low, according to the article from AlterNet, which is a progressive news website.

Professor Robert Correll, chairman of the Arctic Climate Impact Assessment said that newly invented ice penetrating radar showed that the melt water was pouring through to the bottom of the glacier creating a melt water lake 500 metres deep causing the glacier "to float on land. "These melt water rivers are lubricating the glacier, like applying oil to a surface and causing it to slide into the sea. It is causing a massive acceleration which could be catastrophic." Correll stated that one particular glacier puts enough fresh water into the sea in one day to provide drinking water for a city the size of New York for a year.

Correll believes that the estimates of a 20 to 60 centimeter sea level rise this century from the IPCC report in February had been "conservative" and feels that it would be at the upper end of this range at a minimum. Some scientists fear that number could be 2 metres (200 centimeters), which would obviously have catastrophic effects for European and U.S. coastlines.

Using probes stuck high (up to 1,500 feet) on two towers to measure greenhouse gases, a group of scientists from the Lawrence Berkeley National Laboratory in California are trying to judge how accurately air experts have estimated emissions from power plants, farms, factories and automobiles. The California Greenhouse Gas Emissions Project (CALGEM), as it is called, was funded by the California Energy Commission.

The group determined in 2003 that greenhouse gases produced from burning fossil fuels could be measured regionally, which may help determine how much of the pollution can be blamed on humans according to the article in the San Francisco Chronicle..

How does it work? Twice a day the devices suck in air, which travel down a tube to the ground where CO2 and methane are analyzed.

Baseline data collected today will help scientists judge how the level of gases change over time, said Gene Zastrow, vice president and general manager of the Sutro Tower. Inc., which is one of the towers used in the study. According to Zastrow, part of the challenge is to determine how much of the gases are human created and how much are from natural fluctuations. Once they figure that out they can take current estimates of greenhouse gas emissions and use models and monitoring data to determine if those estimates are correct.

The scientists would eventually like to have measuring devices employed at up to 10 California sites at a cost of $10 million dollars to set up and $2 million a year to operate.

Here is a link to the project's website.

The combined global land and ocean surface temperature for September 2007 was the 5th warmest on record, according to scientists at NOAA;s National Climatic Data Center in Asheville, N.C. Also, the global ocean surface temperature for September 2007 was the 2nd warmest since records began in 1880. There is nothing in the press release about the global land temperature departure by itself, I guess it was not significant, but it would be nice to know.

In the United States, September 2007 was the 8th warmest on record with a temperature departure of 2.1 F (1.2 C) above the 20th century mean. Records kept since 1895.

Other U.S. highlights.........

-- 1000 daily high records were broken
-- 38 of 48 states were warmer than average, 10 were near average and 0 cooler than average.
-- 12th warmest September on record for Alaska.
-- Drought impacted 46% of the nation.
-- Lake Superior was at its lowest level on record for this time of year.

The world's oceans are one of the two major carbon "sinks" for CO2 emissions, while the other is the land biosphere. The two combined typically absorb 1/2 of the CO2 into the atmosphere, but a 10-year study by researchers from the University of East Anglia showed that the uptake of CO2 by the North Atlantic Ocean halved between the mid 1990's and 2002-2005, which could accelerate global warming. There was also evidence of this trend in the southern Ocean, but not as great or as sudden, according to the Reuters article

The findings surprised lead authors Dr. Ute Schuster and Professor Andrew Watson. "We expected that the uptake would change only slowly because of the ocean's great mass," said Schuster.

The data for the study was collected by specifically equipped merchant ships.

The scientists are still not sure why this is happening, but according to Professor Watson it could be partly a natural oscillation or a response to recent rapid global warming.

One proposal to increase the ocean's ability to absorb CO2 is to create a network of pipes to improve circulation of water far below the surface, but Professor Watson was skeptical of the long-term impact of this particular proposal.

Kind of a slow day in the global warming department, so I figured I would do a post on the 10-year trend of the world's surface water temperature departures. The data is based on satellite measurements taken over the past 10 years. I am comparing data taken from the third week of October for each year. The reds and oranges are above normal surface water temperatures, while the blues are colder than normal. See if you can find any trends. Also, can you tell which years there was an El Nino or a La Nina? Hint: El Nino is the unusual warming of the eastern and central equatorial Pacific surface waters, while a La Nina is the opposite (cool phase). I will start with 1997 and end with our most recent image from yesterday. Images are courtesy of NOAA.

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

James Lovelock, scientist, pro-nuclear environmentalist and inventor of the Gaia theory says that a rapid cutback in greenhouse gas emissions could accelerate global warming. By the way, the Gaia theory states that the earth behaves like a single, super organism.

Lovelock says that current global warming is being offset by global dimming, in which aerosol particles from industrial pollution are causing 2-3 degrees of cooling.

Keep in mind, this is all assuming that global emissions are stopped suddenly, something that in my opinion is highly unlikely to ever occur, unless the whole world gets nuked, and then it wouldn't really matter would it.

Prof Lovelock believes that even the gloomiest predictions of the Intergovernmental Panel on Climate Change are underestimating the current severity of climate change because they do not go into the consequences of the current burden pollution in the atmosphere which will last for centuries, according to the article from the Telegraph.

Lovelock argues that we have set off a vicious cycle of "positive feedback" in the earth system whereby extra heat in the atmosphere, no matter what the source, is amplified, causing yet more warming. There's that that word "positive feedback" once again! (from the previous post).

Lovelock says that the IPCC's climate models fail to take into account that the earth is a living system where life in the oceans and land takes an active part in regulating the climate. If the models included the whole earth system in their equations they would show the global temperature becoming stable once again after the global temperature suddenly rises 6 celsius after the CO2 in the air exceeds 500 ppm. This contrasts with the current IPCC models that predict that temperature rises and falls smoothly with increasing or decreasing CO2.

Professor Lovelock still argues that greenhouse gas emissions should be cut and that deforestation needs to be lessened even though he feels that the changes are inevitable.

Do you agree with Lovelock's analysis?

The widely accepted idea, based on climate modeling, that man-made global warming will accelerate itself (positive feedback) by creating more heat trapping clouds, such as cirrus is being challenged by a new study from the University of Alabama at Huntsville, which showed that individual tropical warming cycles, based on 30 to 60 day tropical temperature fluctuation data saw a decrease in coverage of heat trapping cirrus clouds (a strong negative feedback). As the tropical atmosphere warms, cirrus clouds decrease, which allows more infrared heat to escape from the atmosphere to outer space.

Dr. Roy Spencer, a principle research scientist at UAH, was surprised by the results. "The big question that no one can answer right now is whether this enhanced cooling mechanism applies to global warming," said Spencer. According to the study, posted on ScienceDaily, the only way to see how these new findings impact global warming forecasts is to include them in those same computerized climate models.

"Right now, all climate models predict that clouds will amplify warming. I'm betting that if the climate models' "clouds" were made to behave the way we see these clouds behave in nature, it would substantially reduce the amount of climate change the models predict for the coming decades," said Spencer.

The results of this research were published recently in the American Geophysical Union's "Geophysical Research Letters" on-line edition.

A study from the University of Wisconsin at Madison determined that forest fires during a 60-year period had the greatest direct impact on carbon emissions from the boreal forest system, which is second in size among forests only to the tropical rainforests.

The study, posted in the journal Nature used a computer model to simulate the carbon balance of one million square kilometers of the Canadian forest over the past 60 years, to determine the relative impacts of climate and disturbance by wildfire. The researchers found that the effects of CO2 and climate (temperature/precipitation) varied from year to year, but generally balanced out over time and area.

According to The ScienceDaily version, the researchers believe that fires shift the carbon balance in multiple ways, a couple such as the burning of organic matter which quickly releases large amounts of CO2 and the fact that after a fire the forest canopy will allow more sun to reach and warm the ground, speeding decomposition and CO2 emission from the soil.

According to S. Tom Gower, a UW-Madison professor of forest ecology, the boreal forest has been thought as a carbon sink historically, but based on the new study the forest has become a smaller sink and may actually be shifting toward becoming a carbon source.

Though the model is not currently designed to forecast future conditions, Gower says, "Based on our current understanding, fire was a more important driver (of the carbon balance) than climate was in the last 50 years. But if carbon dioxide concentration really doubles in the next 50 years and the temperature increases 4 to 8 degrees Celsius, all bets may be off."

A very recent story posted on RealClimate.org explains that there is increasing evidence that the hypothesized carbon cycle positive feedback has begun based on analysis of the oceans and their CO2 uptake.

According to the article, the ocean has a tendency to take up more carbon as the CO2 concentration in the air rises, because of Henry's Law, which states that in equilibrium, more in the air means more dissolved in the water. But, if you have warming at the surface then there tends to be some stratification of the ocean water (more warm and cold layers, which create barriers to water mixing). Less mixing means less replenishing of the surface waters by deep waters, which will mean less CO2 absorption. As I have stated in earlier pieces, the combination of the land biosphere and the oceans take up more than 1/2 of the carbon emission on the planet, but if climate change were to slow the uptake or even reverse it, then, according to the RealClimate story, climate forcing from fossil fuels would accelerate (positive feedback).

A study done by Le Quere et al. from 2007 found that the southern ocean has begun to actually release carbon since about 1990. The researchers believe this could be due to a windier Southern Ocean, as the wind can open ventilation channels between the atmosphere and deep ocean. The ventilation channels would let the high concentrations of CO2 from the deep oceans to ventilated out into the atmosphere. But, these same ventilation channels could end up letting atmospheric carbon in as the atmospheric CO2 concentration supposedly gets higher (back to Henry's Law).

A decrease in the North Atlantic Ocean uptake is also shown by the recent study from Schuster and Watson (2007), which I recently blogged about on October 22nd. (You will have to scroll down to the 22nd to see it)

After reading the story, it is obvious that there are still a lot of unanswered questions about the impact of climate change on carbon cycle feedback. As the story says, it is still poorly understood.

Thanks to Steve Bloom for the link

Scientists using GPS measurements from stations on the Greenland bedrock since 2001 have determined that Greenland is indeed floating upwards at up to 4 centimeters (~1.6 inches) per year, and that rise has dramatically accelerated since 2004.

What is causing this? According to the study, posted on NewScientist, it is the shrinking Greenland ice cap. "The Earth is elastic and if you put a load on top of it, then the surface will move down; if you remove the load, then the surface will start rising again," explains Shfaqat Khan of the Danish National Space Center in Copenhagen.

Khan and his team have determined that the southeastern tip of Greenland is most definitely rising upwards and that rise has clearly accelerated over the past few years. Khan is still not quite sure what caused the acceleration, "but it could be that more melt water is flowing into crevasses which is making the glaciers flow into the ocean faster," said Khan. (Remember the moulin piece I blogged about recently.) They also calculated that some of the ice is also lost through melting.

No, we are not under imminent attack...............

A large group of international oceanographers just recently finished deploying 3000 robots, which will observe the effect of climate change on the world's oceans in real time, according to an article from ABCNews in Australia.

The robots are called Argo floats. The Argo float, which is 1.5 meters tall, (~ 5 feet) is dropped to depths as much as of two kilometers (a little over a mile) below the surface and measures temperature, salinity and pressure. After the data is collected, the robot pops up to the surface and sends the data back via satellite to control centers in the U.S. and France. With the full deployment, data from every ocean on the globe will be available with average coverage of one robot per 3 degrees latitude and longitude.

According to professor Dean Roemmich from the Scripps Institute of Oceanography in California, Argo is similar to the real-time satellite analysis of the surface waters, which meteorologists such as yours truly depend upon during a regular basis. The difference is that Argo is looking at the sub-surface ocean, which gives scientists a better understanding of how global warming is affecting the world's oceans.

Argo data might also help scientists better predict intensity of tropical cyclones by improved measurements of the heat content of the waters that a storm is about to move over. Scientists in Australia also think that the Argo could help them predict upcoming drought.

Here is a link to a photo of Dean Roemmich (center), co-chair of the Argo International Steering Group showing off one of the Argo floats.

Interesting report just released from NASA Tuesday............

A team of NASA and University of Washington scientists have detected an ongoing reversal in the Arctic Ocean circulation which is triggered by atmospheric circulation changes that vary on decade-long time scales. What does this mean? It means that the scientists have determined that not all off the large changes in the Arctic climate that we have seen in recent years are a result of long-term trends associated with global warming.

The study was done by looking at data from 2002-2006 which measured changes in weight of columns of Arctic Ocean water from the surface to the bottom. The weight is influenced by factors such as the height of the ocean's surface and its salinity. A saltier ocean is heavier and circulates differently than one with less salt.

The results of the study suggested that the Arctic Ocean circulation (AO) changed from the counter-clockwise pattern exhibited in the 1990s to the clockwise pattern, which by the way was the dominant circulation prior to 1990. The authors of the study attributed the reversal to a weakened AO, which is a large atmospheric circulation pattern in the far northern hemisphere. The weakening AO reduced the salinity of the upper ocean near the north pole, decreasing its weight and thus changing the ocean's circulation.

"Our study confirms many c