Putting aside the question of whether the Medieval Warm Period was a global or regional event, I wanted to touch on the Norse colonies in Greenland. Greenland was explored and named by Erik the Red between 982 and 985. Most accounts indicate he used the name Greenland to lure settlers from Iceland to join him at this far-flung outpost. Erik and found two areas in the southwest suitable for settlement, with grasslands and small stands of alder and birch. Most of the rest of the island was covered with arctic tundra, snow and ice, much as it is now. Some of Greenland's ice is over three kilometers deep. The first group of settlers - 24 boatloads - set out from Iceland in the summer of 986. Only 14 ships finished the journey, with the other 10 forced to turn back or lost at sea.

The Norse colonies grew and prospered for at least the first 200 years in Greenland, with the population peaking at about 5000. Ships from Norway and Iceland visited once or twice a year, and the colonists traded live falcons, polar bear skins, narwahl tusk, walrus ivory and hides for timber, iron, tools and even some luxuries. The Greenlanders had cows, sheep and goats which grazed when the weather permitted but had to be housed in barns during the harsh winter months. As the Medieval Warm Period gave way to the Little Ice Age, Greenlanders kept their livestock in their homes for the added warmth. This was happening as early as the 12th century.

As the years passed, the farmland lost its fertility and the cutting of trees for fuel and for the production of charcoal lead to erosion. The Norsemen were stubborn, proud people. They saw themselves as European and continued to pursue a European lifestyle. The Inuit, who also were living in Greenland in the Middle Ages, adapted well to the changing climate. The Norsemen refused to adopt the clothing and hunting gear which allowed the Inuit to thrive, believing the European way to be superior.

The last written record from the Greenland Norse colonies dates from 1408. A few Norsemen remained in Greenland into the 16th century.

It's fairly clear the Greenlanders lived a hard scrabble life. They were accustomed to hardship. A program on the Little Ice Age from the History Channel mentioned that even during the period of climate optimum, most Europeans had few resources. A failed crop lead to famine. The same must have been true in Greenland. Climate change is not believed to be the sole cause of their demise, but was probably the primary stressor. They had little economic "cushion" to fall back on.

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.

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.

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.

This week's Headline: Earth video is part 2 of Katie Fehlinger's interview with AccuWeather.com's Ken Reeves, discussing climate ideas from 30 years ago.

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.

Last month we learned a lot about paleoclimatology, especially about ice core research. A new study out of NASA's Jet Propulsion Laboratory examines a different kind of paleoclimate record.

Researchers studied Egyptian records of annual Nile water levels between 622 and 1470 A.D. at Rawdah Island in Cairo. Water levels were critically important for agriculture and the records are considered to be "highly accurate." These water records were cross referenced with records of auroral activity kept in northern Europe and the Far East. These records are also considered accurate, as people believed auroras were portents of disaster.

Some clear links were found between solar activity and climate variations, in particular an 88- and a 200-year cycle. These links appear to be connected to the North Atlantic Oscillation, a large scale seesaw in atmospheric mass between the subtropical high and the polar low.

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."

Discovery of fossil evidence of a creature similar to the modern-day hippopotamus found on the Norwegian archipelago of Svalbard indicates the climate in that Arctic region 55 million years ago may have been more like that of Florida.

Appy Sluijs of Utrecht University in the Netherlands says forests grew in the Arctic when atmospheric carbon dioxide was at about 1000 parts per million. Currently CO₂ is at about 390 parts per million.

Scientists believe that the melting of frozen methane along with volcanic activity may have led to those high levels of carbon dioxide.

Just yesterday I wrote about the ancient hippos that lived 55 million years ago. Today, new research is coming out about what caused that massive, ancient warming. Scientists call the period the Paleocene-Eocene Thermal Maximum (which is much harder to type than PETM).

A description of this figure can be found at it's source, globalwarmingart.com.

Scientists have found evidence that a massive increase in volcanic activity which baked carbon-rich sediments and released enormous quantities of greenhouse gases from the Earth into the atmosphere. That produced enough warming to melt some of the methane hydrates frozen in cold sea beds. As those thawed, the methane was released into the atmosphere, further boosting this ancient global warming.

Methane hydrates pose one of the biggest mysteries and one of the greatest potential disaster scenarios of global warming - if they start to melt, either from permafrost or from vast undersea deposits, climate change will be out of our hands.

A new study in the journal Nature reconstructs the past 270 years of Atlantic hurricane history using sediment samples to reconstruct water temperature and coral samples to reconstruct wind shear. Coral density depends on precipitation at the time of growth, which is largely dependent on the strength of trade winds. When the trade winds are strong, wind shear is strong as well.

The results of the study show that several periods of enhanced hurricane frequency, more than four major storms on average per year, have occurred several times over the 270 year period of their reconstruction, with no link between warm sea and air temperatures and the higher hurricane frequency. Researchers point out this data does not predict future hurricane activity.

The full study can be found in this week's edition of Nature, a subscription-only site. One of the points made in the summary of the full study is that more rapid warming in the atmosphere relative to the ocean from the 1970s to the 1990s may have caused the low hurricane frequency during that time.

Mount Kilimanjaro, the highest point in Africa, has been losing snow and ice cover for more than 100 years. The ice cap was about 12.5 square miles in 1889, based on a rough survey. In 2003 it was just over 1.5 square miles. Some have pointed to this melting as a sign of global warming. A new article in American Scientist suggests this is not the case.

Researchers Philip W. Mote and Georg Kaser confirm that glaciers at the mid-latitudes have been shrinking due to atmospheric warming, but they say that the glaciers on Kilimanjaro - located just 3 degrees from the equator - have shrunk for different reasons, probably unrelated to AGW. In fact, most of the shrinkage occurred prior to 1950 and the most probable explanation for the changes have to do with reduced snowfall and increased solar radiation.

Past climate reconstructions from nearby Lake Victoria indicate that several decades in the late the 19th century were wet, followed by a sharp decline in precipitation amounts. As precipitation decreased, cloud cover decreased as well. Increased incoming solar radiation sped the process of sublimation (ice changing phase to water vapor). Sublimation can take place in air temperatures well below freezing, but requires about eight times as much energy as melting. These changes in the regional climate shifted the glaciers' mass balance, causing them to shrink. The shape of the summit and of the glaciers also play a role in the changes in the past century.

The researchers say that if global warming has played a role in the shrinking of Kilimanjaro's ice, it's only been in the past few decades. It is possible that greenhouse gas accumulations have changed atmospheric circulation and precipitation patterns across the region.

This article is one I'd recommend to anyone interested in gaining some understanding of how glaciers grow and shrink and what climate factors can play a role in their cycles. It contains a lot of information, but is written in an engaging and nontechnical way that anyone can grasp.

Some have argued that the increases in temperatures around the world have less to do with a warming Earth and more to do with the urban heat island effect--as more and more corners of the Earth are defoliated, paved over, and built up, weather stations that were once located in balmy glens are now surrounded by steamy urban concrete and blacktop jungles.

The Pittsburgh Tribune-Review's web site contains an opinion article that explores this subject (Helping Along Global Warming), and, more interestingly, links to a web site (Watts up With That?) that documents some of the locations of California weather stations from which NOAA draws temperature data.

A couple of the more interesting weather station locations in California? One is a few feet away from a barrel that has been converted into a stove that is used to burn garbage. Another is located in a parking area and has a receptacle for trash and a container for dispensing dog-poop-collection bags attached to it. Yet another is located in an airport within ten feet of where jet aircraft (and their very hot exhausts) take off. Many are located in or near parking lots.

Something to think about, but bear in mind that the Tribune-Review is an ultra-conservative paper, so don't necessarily expect a nuanced view of global warming.

By the way, our own Jesse Ferrell takes a more in-depth look at this topic as a guest blogger post in the Global Perspective blog.

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.

The world's oldest DNA found at the bottom of a 2 kilometer thick ice sheet in Greenland might offer some clues to the causes of global warming. An international study which was published in the journal "Science" was co-written by University of Alberta Glaciologist Dr. Martin Sharp. The material, which was made up of tree, plant and insect DNA suggested that the average temperature in the boreal forests of southern Greenland between 450 and 900 thousand years ago was 10 celsius (50 F) in the summer and -17 celsius (1 F) in the winter. On the ice surface today, the average summer temperature is -8 celsius (18 F) and -30 celsius (-22 F) for the winter. In the article from CTV News, Dr. Sharp theorizes from the research that natural processes can and do produce climate change, perhaps big enough to produce effects similar to those that are widely predicted as a result of Anthropogenic Global Warming (AGW/ human induced global warming), though, he cannot prove it.

NOAA has just released the climate data for the first half of 2007. I will list some of the more notable results.

1. The first half of 2007 (Jan-Jun) was warmer and drier than normal for much of the U.S.

2. This was the 18th warmest January through June period in the U.S. since records were kept (1895). The period was 1.3 degrees F (0.7 C) above normal.

3. The combined global land and ocean sea surface temperature for the January through June period was 2nd warmest on record.

4. Just looking at the ocean sea surface temperatures globally for the Jan-June period, it was the 6th warmest in the 128 years of record keeping.

5. Warmest June on record at the South Pole.

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.

In a United Nations report, the world experienced a number of record-breaking weather events in early 2007.

The World Meteorological Organization (WMO) said that land based temperatures for the world during January and April were the warmest since records began in 1880.

The organization also noted some of the following extreme events......

--Severe monsoon floods across South Asia.
--Abnormal heavy rain and flooding for northern Europe, China, Sudan, Mozambique and Uruguay.
--Heatwaves in southeastern Europe and into Russia.
--Rare snowfall for south Africa and South America recently.
--The Arabian Sea had its first documented cyclone in June, which affected Oman and Iran.

According to the Reuters article "Early 2007 saw record-breaking extreme weather: U.N. ", the Intergovernmental Panel on Climate Change (IPCC), which is a UN umbrella group of hundreds of experts, has noted an increasing trend in extreme weather events over the past 50 years and has said that these irregular patterns are likely to intensify under global warming.

The WMO is currently working on an early warning system for extreme events, which would certainly save lives, especially in the less developed countries.

There was a story last week, which most of you already know about, in that Mr. Steve McIntyre pointed out some errors in the NASA GISTEMP analysis for some stations across North America, which in the end made 1934 the hottest year in the U.S., and not 1998. His findings also caused the mean U.S. anomalies for the years 2000-2006 to be reduced by 0.15 celsius. Well, some of you were wondering if the NASA GISS team would respond, and so they did. Here is the link from RealClimate. The team acknowledges Mr. McIntyre and his findings, but plays down the significance of the error.

NOAA just released some July climate statistics for the U.S. and world. Here are some of the highlights from the press release I just received.........

--The global average temperature (combined sea and land) was the seventh warmest on record for July.

--According to NOAA, cooler-than-average ocean surface temperatures in the central and eastern equatorial Pacific (trend toward La Nina) contributed to a global temperature average for July that was lower than recent years.

--While above-normal temperatures covered most land masses globally, Argentina was more than 5 degrees F (3 C) cooler than average.

U.S. statistics for July.....

--Record and near-record warmth in the western U.S.

--Much of the eastern and southern U.S. experienced cooler-than-average temperatures.

--46% of the contiguous U.S. was in some stage of drought by the end of July.

--July 2007 was the 15th warmest on record in the U.S.. (records go back to 1895)

--Florida was the only state warmer-than-normal east of the Mississippi in July.

--Warmest July on record in Montana, Wyoming and Idaho.

--In Boise, Idaho July averaged 9 degrees above normal, making it the warmest month ever!

--The nation's residential energy demand was around 4 % lower than normal thanks to the cooler conditions in the heavily populated eastern U.S.

--80% of the Southeast was in a drought, with the most severe conditions in the northern half of Alabama.

--Overall for the U.S. as a whole, July rainfall was near normal.

--Third wettest July on record for Texas and Louisiana

I found an interesting research piece on the Discovery Channel online. University of Michigan researcher Christopher Poulsen and colleagues have tried to reproduce what might have happened on the supercontinent Pangea during the late Paleozoic era when polar ice melted, which was about 300 million years ago.

The research team used the same global circulation models which many current climate scientists are basing their future forecasts on. Take note: the models had to be adjusted to be more coarser due to a lack on knowledge about the geography on the planet 300 million years ago. The models showed that melting large to moderate sized high latitude ice sheets resulted in a reversal of tropical trade winds and big expansions of low latitude desert areas into what had been warm, temperate forests. The team also found that when CO2 was high in the atmosphere, ice sheets were small and vice versa.

Poulsen admits that the analogue is certainly not perfect, but it gives evidence that changes in CO2 and glaciation lead to enormous change on earth.

The National Oceanic and Atmospheric Administration (NOAA) has just released its preliminary temperature and precipitation data for the summer of 2007 (June-August).

In the press release that I just received, NOAA states that the summer of 2007 was the sixth warmest on record for the contiguous U.S.. The global surface temperature was seventh warmest on record. Here are some other findings in the report......

--August 2007 was the second warmest on record in the contiguous U.S.

--More than 2000 new daily high temperature records were set across the southern and central U.S. during a long-lasting heatwave.

--The summer of 2007 in the U.S. was 1.7 F (1.0 celsius) above the 20th century mean.

--Warmest summer on record for Utah and Nevada.

--Fourth warmest summer on record in Alaska.

--Texas and Oklahoma were cooler than normal for the summer due to all that rain.

--The nation's energy demand was 8% higher than normal.

--More than 30 all-time high temperature records were tied or broken in the U.S.

--Warmest August on record for West Virginia, Kentucky, Tennessee, North and South Carolina, Georgia, Alabama, Florida and Utah.

--The summer overall was drier than average for the nation.

--Texas had its wettest summer on record.

--Driest summer on record for North Carolina.

--At the end of August, drought affected approx. 83% of the Southeast and 46% of
the contiguous U.S.

Global Highlights

--Combined land and ocean surface temperature for August was eighth warmest on record. For land only, it was the third warmest on record. For ocean surface temperature, it was the ninth warmest August on record, because, according to NOAA, there was the ongoing development of La Nina, or cooler-than-normal conditions over the equatorial Pacific.

--A heavy monsoon in South Asia produced widespread flooding and thousands of deaths.

Scientists from the California Institute of Technology believe that they have confirmed the link between carbon dioxide levels and warmer ancient climates.

In the article from Scientific American.com, Geochemists Rosemarie Came, John Eiler and colleagues studied the stored rare isotopes of carbon and oxygen in the calcium carbonate shells of fossilized sea creatures. The group was able to determine the temperature for different periods by looking at the number of carbon and oxygen neutron pairings in the ancient shells. The scientists counted the couplings in the fossilized shells from the Silurian (444 to 416 million years ago) and Carboniferous (359 to 299 million years ago) eras and discovered, contrary to earlier findings, that higher CO2 concentrations of the Silurian era were indeed linked to higher tropical ocean temperatures.

The team plans to refine the new method and use it to assess temperatures during other periods, such as the Paleocene-Eocene thermal maximum that occurred around 55 million years ago when there was a sudden shift from a relatively cool to an extremely hot climate.

A study out of the University of Bristol in Britain has determined that huge belches of methane from ancient bogs, in what is now southeastern England, likely amplified global warming some 55 million years ago.

In the article from the National Geographic Online, lead author of the study Richard Pancost and colleagues studied the chemistry off 55 milion year old sediments from a wetland. From their research, the team concluded that the warm, wet weather during that period likely accelerated the rotting plant material in the bog, which in turn triggered the large methane burbs (emissions).

Methane is a key greenhouse gas and assuming these methane burbs were widespread, the increased methane flux could have amplified the warming occurring at that time. Some scientists also feel that a similar process could play a key role in modern warming, according to the article. Currently, methane appears to be seeping out of once frozen bogs in Siberia.

Dave Reay, a climate scientist at Edinburgh University, who is not affiliated with the research said, "The wetland methane feedback effect could be equivalent to wiping out all emissions cuts set out in the Kyoto Protocol (the 1997 greenhouse gas reduction treaty)."

A new study out of the University of Southern California casts serious doubt that the ending of the last ice age was driven by an increase in atmospheric carbon dioxide.

According to Lowell Stott, lead author of the study, deep-sea temperatures rose 1300 years before the tropical surface ocean and well before the rise in atmospheric CO2, which rules out CO2 as the driver of the ending of the last ice age. The findings suggest the rise in greenhouse gas was likely the result of warming and may have accelerated the meltdown. The researchers studied a unique sediment core from the west Pacific composed of fossilized surface and bottom dwelling organisms.

Stott makes it clear that he is not saying that CO2 does not affect climate, but as he said, "You can no longer argue that CO2 alone caused the end of the ice ages."

So where did the warming come from?

Using water's salinity and temperature to trace the origin of the energy needed for the warming appeared to come from the Antarctic Ocean, in which water was transported northward over 1000 years via deep-sea currents, which is supported by carbon-dating evidence. The researchers also found a correlation between melting Antarctic sea ice and increasing springtime solar radiation over Antarctica suggesting a possible energy source because of sea-ice albedo feedbacks.

According to the article from EurekAlert.org, if CO2 caused the warming, one would expect surface temperatures to increase before deep-sea temperatures, since the heat slowly would spread from top to bottom. Instead, carbon-dating showed that the water used by the bottom-dwelling organisms began warming about 1,300 years before the water used by surface-dwelling ones, suggesting that the warming spread bottom-up instead.

Stott, who is an expert in paleoclimatology is also a reviewer for the IPCC.

Archaeological researchers have concluded through a study of sediment and fossil samples that climate change, in the form a very long term drought, explained early mankind's exodus from Africa to other parts of the world.

According to the article from the Timesonline, researchers believe a prolonged drought between 90,000 and 135,000 years ago created such stresses on Homo sapiens that the population had crashed. This could help explain why mankind is thought to be descended from a relative handful of people in Africa.

"Tropical Africa was extraordinarily dry about 100,000 years ago. Archaeological evidence shows relatively few signs of human occupation during the mega-drought period," said Professor Andrew Cohen, of the University of Arizona. A study of sediment core samples from Lake Malawi, one of the worlds deepest lakes (now 2,316 ft), indicated that the water level dropped by at least 1,986 feet, making it only 410 feet deep during that mega-drought period. During that period, the area around the lake would have turned into a semi-desert, greatly limiting the resources for primates.

The scientists believe that the period for the human expansion out of equatorial Africa would have been between 90 and 70 thousand years ago.

ADDED CORRECTION

By the way, Dr. Joe Sobel has a new post in the global warming center on the October heat wave, and is this evidence of climate change?

A research team from the University of York has studied the relationship over the past 520 million years between earth climate and extinctions. According to the press release, evidence shows that global biodiversity is relatively low during warm "greenhouse" phases and extinctions are relatively high. The reverse is true in cooler phases. How did they come to that conclusion? Using fossil records, the team matched data sets of marine and terrestrial diversity against temperature estimates during the 520 million year period.

The study was done by York student Gareth Jenkins and supervised by Dr. Peter Mayhew and University of Leeds Professor Tim Benton, who are population ecologists.

According to the study, four out of the five mass extiction events were associated with greenhouse phases. The largest mass extinction event of all, the End-Permian, occurred during one of the warmest ever climatic phases with an estimated extinction of 95% of animal and plant species. A new 'mass extinction event', where over 50% of animal and plant species would be wiped out could occur if global temperature predictions over the coming centuries come true.

"If our results hold for the current warming, the magnitude of which is comparable with the long-term fluctuations in earth climate, it suggests that extinctions will increase," said Dr. Mayhew.

A short time back I posted the last seven years or so of the global sea-surface temperature anomalies. A reader asked if I could do a post on the global surface temperature anomalies. Well, here it is, courtesy of the NCDC. The maps only go back to 2000. But, I think it is easier to visualize it than look at pages of numbers. If you want to see the raw, numerical global land temperature anomaly data going back to 1880 here it is.

2000 world surface temperature anomalies (All images courtesy of the National Climatic Data Center)

2001 world surface temperature anomalies

2002 world surface temperature anomalies

2003 world surface temperature anomalies

2004 world surface temperature anomalies

2005 world surface temperature anomalies

2006 world surface temperature anomalies

Longer term global surface anomaly (black line) and trend (black dotted) since the 1950's.

And just for fun, here is the global precipitation anomaly chart going back to 1900. Not too many trends here, other than the dryness early in the century and the wet period mid-century.

What do make of all this?

October 2007 was the sixth warmest on record globally for surface temperature, according to a news release from the National Oceanic and Atmospheric Administration (NOAA).

Here are some of the U.S. highlights from October......

--The average temperature for October in the contiguous U.S. was 2.1 F (1.2 C) above
the 20th century mean, making it the 9th warming October on record, based on
preliminary data.

--Delaware, Maryland, New Jersey, Pennsylvania and Rhode Island had their warmest
October on record. For the entire Northeast, it was the second warmest October.

--Energy demand across the nation was 15% below average. I can vouch for that
after being pleasantly surprised with my $68 electric bill for October.

--Rainfall across the country was slightly above normal, which really does not mean
much, since you really need to break those numbers down regionally.

--The 2007 fire season was the second worst on record in the U.S., 2006 was the worst.

I just received this press release with my email, but their link to the story has not been posted as of this writing. When it is I will include the link.

Also, I realize we have had some issues with global warming site, especially slowness. I have forwarded some of the concerns from you, including myself, to our techs and they are looking at the problem.

A recent study just reported in the December 20th issue of Nature shows that a large part of the greenhouse gases during the Palaeocene-Eocene thermal maximum phase 55 million years ago was injected as a result of a chain-reaction of events. This period, which saw rapid global warming, is seen as the best fossil analogue to predicted future climate trends, according to the Science Centric article.

The Palaeocene-Eocene thermal maximum was caused by a relatively rapid increase increase in carbon dioxide concentration in the atmosphere, which was determined using sediments that accumulated 55 million years ago on the ocean floor in what is now New Jersey. Through a chain-reaction of events CO2 concentrations likely became higher through intense volcanism and warmed the planet as a result. This is interesting, as you would think the massive amounts of ash and dust particles released from all the eruptions would lead to a cooler planet, as we have documentated in much more recent history. Anyway, as a result, marine methane hydrates, which are ice-like structures, melted and released large amounts of methane into the atmosphere, which further accelerated the warming (positive feedback) since methane is a strong greenhouse gas. The end result was a 6 degree celsius increase in temperature.

The research team says that the study confirms that climate warming can enforce mechanisms that inject massive amounts of stored carbon into the atmosphere and that current/future warming will likely see similar feedbacks.

Happy Holidays to everyone! Time for me to take a much needed break from this stuff and get recharged in time for Wednesday. I will try to keep the comment section up to date as best I can, but family comes first. Regards, Brett

Once again we go back to the last severe global warming episode (Paleocene-Eocene Thermal Maximum or PETM) 55 million years ago, thanks to an article from Discovery News.

Marine scientists from California have determined that the massive accumulations of the mineral barite on the bottom of the ocean indicates that the PETM was accompanied by several thousands of years of ocean plant life kicking into high gear. That massive increase in ocean plant life captured excessive carbon from the atmosphere and deposited it to the ocean floor where it was buried. Barite, otherwise known as barium sulfate, is a good indicator of ocean plant productivity according to Adina Paytan, an oceanographer at the University of California. When organisms in the life-rich upper waters die, they sink to the sea floor along with the barium since all living things contain a lot of barium in their tissues. In very deep water, the barium reaches its saturation point in the water and combines with sulfur to create the mineral barite.

According to the study, the large accumulations of barite may very well indicate that the direct products of living organisms may have cooled the atmosphere during the PETM.

"This study is suggesting that the peaks in barite observed in the deep sea...are accurately reflecting changes in the accelerated, though temporary, sequestration of carbon by one process -- higher algal production," PETM expert James Zachos told Discovery News.

That doesn't mean Earth is likely to repair the damage done by current global warming in any timely way, however, he cautions

According to Zachos, the accumulation of barite went on for 170,000 years, which indicates that it takes much, much longer to cool off a hot earth than to heat up a cool planet.

I know many of our readers are already aware that 2007 was on pace to become the 5th warmest on record globally, while in the contiguous U.S., 2007 was going to make the top-ten list, according to NOAA. This preliminary data will be updated later this month as the rest of the December data is incorporated into the set. The official results for 2007 will not be finalized until spring.

Here is a more detailed look at the early NOAA estimates as listed by the ScienceDaily article.......

1. Globally

--The combined land/ocean surface annual temperature is expected to be near 58 F, which would make 2007 the 5th warmest since records began in 1880.

--Assuming the above is correct, this will make 7 of the 8 warmest years on record to have occurred since 2001 and the ten warmest will have all occurred since 1997.

--The rate of warming since 1976 has been about 3 times faster than the century-scale trend.

--The largest warm anomalies were from eastern Europe to central Asia.

--The greatest warming during 2007 was in the northern latitudes of the northern hemisphere.

--2007 continued the trend of end-of-summer Arctic sea ice extent reductions of about 10% per decade since 1979. Actually, 2007 set a new record.

2. Contiguous U.S.

--The annual average temperature will be near 54.3 F or 1.5 degrees above the 20th century average, making 2007 the 8th warmest on record.

--U.S. residential energy demand was 3% less in the winter which is good news, but it was 8% higher than average in the summer.

John Tierney, a columnist for the Science Times section of the New York Times posted an article which compares recent actual global temperature trends, using different methods, with the Intergovernmental Panel on Climate Change (IPCC) prediction for the 2000-2007 period. Seven years is not very much when you are looking at climate, but it is interesting when when you compare everything on a graph, which is displayed in Tierney's column.

In his column, Tierney raised a question originally posed by Dr. Roger Pielke, Jr. (professor of environmental studies at the University of Colorado)......Are there any indicators in the next 1,5, 10 years that would be inconsistent with the consensus view on climate change?

A climate scientist suggested comparing what has happened since 2000 with the predictions made by the IPCC. There are many different versions of what has happened with the global temperatures over the past 7 years, as many of our readers are well aware of. There are different groups doing the measuring and some of the measurements are based on satellite data, while others are based on surface data.

Thanks to Pielke, you can compare the IPCC forecast with the actual temperature records of the four different measurements. You can see that the GISS temperature (courtesy of NASA and Dr. James Hansen) is the only one that is still recently within the IPCC range of uncertainty forecast, while the other three have fallen below the IPCC range . Over the past two years, the Remote Sensing Systems (RSS) data has trended the farthest away (cooler) from the IPCC forecast.

Pielke Jr. goes further with a recent post on his Prometheus site, and he shows you the same graph going back to 1990.

Tierney makes a good point here........If scientists can't even agree on what has happened in the past, imagine how much more difficult it is to figure out the future.

It's official, the combined global land/ocean surface temperature for 2007 was the fifth warmest on record, according to NOAA's National Climatic Data Center. Also, 2007 was the tenth warmest on record for the contiguous U.S.. As we mentioned in an earlier post, NOAA had estimated in December that 2007 was on pace to be the eighth warmest on record for the U.S., but colder temperatures in December put an end to that.

Global Highlights for 2007.....

--Global land/ocean surface temperature was 5th warmest on record.
--Global land surface temperature was the warmest on record.
--Global ocean surface temperature was 9th warmest on record.
--7 of the 8 warmest years on record have occurred since 2001.
--The rate of warming in global temperatures over the past 3 decades has
been three times greater than the century scale trend.

Contiguous U.S. Highlights for 2007....

--The average temperature for 2007 was 54.2 F, which is 1.4 F warmer than
the 20th century mean of 52.8 F.
--Temperatures over the past three decades have risen an average of 0.6 F per decade.

Here is the 2007 global annual report from NOAA

Here is the report for December 2007

Image courtesy of NASA.

Last week, NASA's Goddard Institute for Space Studies (GISS) announced that 2007 tied 1998 for the Earth's second warmest year in a century. If you remember, I recently blogged about NOAA's annual temperature report, which stated that 2007 was the 5th warmest on record globally.

The research team, led by Dr. James Hansen, who was recently interviewed by AccuWeather.com, used temperature data from weather stations on land, satellite measurements of sea ice temperature since 1982 and for earlier years ship data.

GISS Global temperature anomaly graph compared to the 1951-1980 mean temperature.

Image courtesy of NASA

According to the GISS report, the greatest warming in 2007 occurred in the Arctic, and neighboring high latitude regions as the loss of snow and ice leads to more open water, which absorbs more sunlight and warmth (positive feedback).

James Hansen on 2008........

"It is unlikely that 2008 will be a year with truly exceptional global mean temperature," said Hansen. "Barring a large volcanic eruption, a record global temperature clearly exceeding that of 2005 can be expected within the next few years, at the time of the next El Nino, because of the background warming trend attributable to continuing increases of greenhouse gases."

Dr. Hansen notes on his website that the Southern Oscillation and the solar cycle have significant effects on year-to-year global temperature change. Since both of these natural effects were in their cool phases in 2007, the unusual warmth of 2007 is all the more notable.

The report also notes that the data processing error found in the GISS temperature analysis in early 2007 does not affect the present analysis.

2007 global and U.S. temperature anomalies with and without the data processing flaw.

Here is the link to a more detailed breakdown of the 2007 GISS temperature analysis.

Here is the link to the GISS history and analysis method.

Researchers from the Australian National University, Newcastle University and the Australian Nuclear Science and Technology Organization have found a way to map past climate patterns by harnessing limestone cave stalagmites as ancient rain gauges, according to an article from The Sydney Morning Herald in Australia.

The research teams suspect that rainwater dripping into caves to grow stalagmites during dry years would seep in slowly enough to have time to pick up trace metals and natural isotopes from the soil. During wet years, the water would move through too fast to leach out the elements. If their theory is correct, the varying levels of isotopic and trace metal concentrations in stalagmites should indicate droughts and deluges in Australia going as far back as 500,000 years ago!

In order for this work, the scientists needed to find a way to accurately age the cave formations. The solution came by finding minute traces of radioactive fallout from the bomb tests of the 1950's and 1960's within the stalagmites.

Dr Ed Hodge, a carbon-dating specialist, said the scientists' research showed stalagmites could be used to reveal past weather patterns. "One stalagmite in Western Australia, known to be 81 years old, showed a 20 per cent decrease in annual precipitation since 1965," closely matching official weather records.

The scientists are now confident they can date stalagmites up to 500,000 years old by dating not man-made fallout but their ratios of natural uranium and thorium. This information can then also be used to help scientists understand climate changes over the same period of time.

I would assume that similar information could be gathered throughout the many limestone caves across the world, not just Australia.

The National Climatic Data Center (NCDC) just released the January climate summary for the contiguous United States, along with some January weather highlights across the globe.

All images courtesy of NOAA/NCDC.

According to the NCDC findings, January was the 49th coolest January on record for the contiguous U.S., or you could say it was the 65th warmest on record. This is based on the data from 1895-2008. January was also the 50th driest on record or 65th wettest, depending on how you want to look at it.

Other U.S. highlights for the month....

--73% of the southeast remained in a moderate to exceptional drought.

--The second largest January tornado outbreak on record (54 unconfirmed tornadoes) happened on January 7th-8th. I wonder where Tuesday night's terrible outbreak will rank for February?

The NCDC will not release the global statistics until the 14th, but they did include some regional highlights.....

--Severe winter weather (cold/heavy snow) impacted parts of China. Some of the worst in 50-100 years.

--January was the hottest on record in Australia for the country as a whole.

--Large parts of the Middle East were exceptionaly cold with unusual snow, especially the first half of the month.

By the way, AccuWeather.com's senior meteorologist and long range weather expert Joe Bastardi just recently posted an article about the global warming debate and computer modeling on the icecap blog. If you are interested in reading about Joe's opinion on the subject, here is the link to the article.

I have had several requests to do a post on this, so here it is...........

Anthony Watts, whose work in checking surface observing stations, that I blogged about not too long ago recently compiled the four global temperature anomaly sets and noted that each set showed a fairly sharp drop of the global temperature anomaly over the past 12 months. You can see the charts right here on his site.

Keep in mind, this is just a 12-month period and the final plot of two data sets were still above normal, but is it the start of a new trend? I think it is way too early to tell, twelve months is a very short time when you are talking climate change. There is just not enough data yet to support the idea from some skeptical sources that the earth is now going to go into a longer term cooling trend. There could be a few reasons for this......La Nina, solar minimum.....check out the sun image below, do you see any sunspots?, and changing atmospheric wind currents. I just do not know for sure, and I do not think anyone really has the definite answer right now, but Anthony's work is applauded. It will be interesting to see how the global temperatures trend over the next couple of years.

Also, Anthony just attended the ICCC conference in New York and blogged about each day he was there. The New York Times John Tierney also writes about the conference. Here is the day 3 report from the Heartland Institute.

The quiet sun

UPDATE.........................

Dr. James Hansen, the director of the NASA GISS program offers his take on the recent cooling trend. You can read it here.

Scientists from the U.S. Geological Survey and the Russian Academy of Sciences, Moscow, have developed a new way to estimate the thickness of sea ice (New Method to Estimate Sea Ice Thickness).

The method uses a new modeling approach--the only model based entirely on historical observations--"uses sea ice motion data to follow parcels of ice backward in time at monthly intervals for up to 3 years while accumulating a history of solar radiation and air temperature to which the ice was exposed."

The report shares information on Arctic sea ice data from 1982 to 2003 that was collected by this new method.

Jon Stewart on the Daily Show recently had archaeologist, historian, and author Brian Fagan on the show to discuss Fagan's book, The Great Warming. Fagan's take is that huge droughts might be the biggest problem associated with global warming, and he bases that prediction on past periods of warming.

By the way, my favorite line was by Stewart, who, toward the beginning of the interview, when talking about how the book has no political agenda said, "I didn't know you were allowed to write about global warming without some type of either denying or accepting political agenda."

Hi folks, Jesse here again. As I always do on the holidays, I curled up on the couch at my mother-in-law's house on Easter Sunday and read a paper (that's right!) edition of Wired magazine, a technological rag that I've followed since its inception in the early 1990's, AKA Ye Olde College Days. On page 25 (the online edition is not out as of this writing, check the Wired website in the near future for the article) was an article entitled "Cooling the Globe? Been There, Done That."

It was about a fellow named William Ruddiman, a retired climatologist, who says that humans started influencing the environment as early as 6,000 BC and that one of their biggest contributions was dying en masse around the year 1600, which reduced CO2 emissions by 10 parts per million.

Rice Paddies - Big Offender? (AP Photo)

Ruddiman's main points were that 1.) If we've been changing the climate that long, we should be able to steer it back on track and 2.) We should concentrate more on things like methane emissions from landfalls and rice farmers.

In a press release that was issued at the end of March, researchers from the Met Office (UK) observed changes in extreme daily minimum (<1.5%) and maximum (>98.5%) temperatures across different world regions since 1950. Here is was they found.....

1. Daily extremes have risen by over 4 degrees celsius (7 degrees F) over the last 50 years.

2. Minimum temperatures, especially those over Russia and Canada are now up to 4 C (7 F) warmer than the middle of the 20th century.

3. Maximum temperatures have warmed 1- 3 degrees celsius (~2-5 degrees F) across Canada and Eurasia.

4. The total area exhibiting positive trends is significantly greater than can be attributed to unforced natural variability.

5. The comparatively small areas of cooling are found to be consistent with unforced natural climate variability.

6. The North Atlantic Oscillation (NAO) is found to have a significant influence on extreme winter daily temperatures for many areas, which is no surprise.

Simon Brown, Met Office Climate Scientist said: "This latest research shows that some extreme events are already increasing. The trend is set to continue with our changing climate having a significant impact, with warmer nights and hotter days in the future".

Here is a link to the abstract of the study in the Journal of Geophysical Research.

The National Climatic Data Center (NCDC) just came out with their March climate report for the U.S. and the world. Here is a sampling of what it says........

--The average global temperature (land/ocean surface combined) for the month of March was 0.71 degrees celsius (1.28 F) above normal (against the 20th century mean) making it the 2nd warmest on record for the month of March (using 129 years of record keeping).

If you don't like those numbers then take a look at a few of the other sources for March 2008 global temperature measurement..........

RSS/MSU data

Global +0.08 c (More detail right here, courtesy of Anthony Watts)
Northern Hemisphere +0.47 c
Southern Hemisphere -0.33 c

UAH/MSU data

Global +0.10 c
Northern Hemisphere +0.43 c
Southern Hemisphere -0.24 c

GISS data

Global +0.67 c

Back to the NCDC March highlights.......

--The global (land only) surface temperature was the warmest on record! The main reason for this
is the fact that much of the Asian Continent (we are talking a major chunk of land here) was well above normal for the month of March.

--March snow cover extent on the Eurasian Continent was the lowest on record.

--The global ocean surface was 13th warmest on record, again thanks tp the warmth around Eurasia (Sorry, nice try La Nina!)

U.S. Highlights from the NCDC.......

--The average temperature for the U.S. was 0.22 Celsius (0.4 degrees F) below normal for March.

--Western snow pack was among the healthiest in more than a decade, which is great news.

In a report released earlier this month, Penn State Paleoclimatologists determined that lower biological productivity during the Cretaceous and Eocene periods may have been the lever that caused supergreenhouse episodes during these periods by controlling cloud formation.

"In today's world, human generated aerosols, pollutants, serve as cloud condensation nuclei," says Lee R. Kump, professor of geosciences. "Biologically generated gases are dominant in the prehuman world. The abundance of these gases is correlated with the productivity of the oceans."

The researchers found that changes in the production of cloud condensation nuclei, the tiny particles around which water condenses to form rain drops and cloud droplets, decreased earth's cloud cover and increased the sun's warming effect 6-10% during supergreenhouse events in which the mean annual temperatures in the tropics were above 100 degrees Fahrenheit and polar temperatures were in the 50-degree Fahrenheit range.

"The Cretaceous was biologically unproductive due to less upwelling in the ocean and thermal stress on land and in the sea," says Kump. "That means fewer cloud condensation nuclei."

How about CO2? Proxies indicated that these prehuman periods never exceeded 4X the current CO2 level, which is not enough for their models to create the supergreenhouse conditions, but changing the earth's albedo could.

The National Climatic Data Center has just released their official global temperature and precipitation statistics for April 2008.

--The combined global land and ocean surface temperature in April was 0.74 F (0.41 C) above
the 20th century mean of 56.7 F (13.7 C) making it the 13th warmest on record.

--April 2008 had the 8th least extensive snow cover extent globally for the 42-year satellite record. I know, I know that seems pretty shocking for many of us in the western and midwestern U.S., including British Columbia and eastern Canada.

--The northern hemispheric sea ice extent for April was below the 1979-2000 mean, but greater than the previous 4 years.

--The southern hemispheric sea ice extent for April was much above the 1979-2000 mean and actually was a record high with a 17.5% greater extent than the mean!

--Lower troposphere temperatures which are measured using satellites and radiosondes on balloons showed the following....

UAH (University of Alabama-Huntsville)...+0.04 F (+0.02 C) above normal or 17th warmest on the UAH scale.
RSS (Remote Sensing Systems)....+0.14 F (+0.08 C) above normal or 15th warmest.

Not the case in the U.S...........

In the Lower 48 of the United States, April 2008 was the coolest April in the past 11 years or 29th coolest April based on records going back to 1895. For more on the U.S. April data see here.

Images are courtesy of the National Climatic Data Center.

The National Climatic Data Center just released their global temperature data for May and also for meteorological spring/fall (March, April, May). Here is a summary.....

--May 2008 (combined land and ocean) was the eighth warmest on record.

--The Mar/Apr/May combined period was seventh warmest on record.

--May 2008 was cooler-than-average over eastern Australia and most of the northern
half of the continental U.S.

--Mean snow cover extent across the northern hemisphere during the spring of 2008 was below normal and the third least during the 1967-2008 period of record.

--Snow cover during the spring of 2008 in North America was slightly above normal.

--But, lower tropospheric (lowest 5 miles of the atmosphere) global temperatures in May that were measured by balloons and satellites were cooler than normal...

UAH data.....May was 5th coolest
RSS data (I just blogged about)...May was 8th coolest.

No doubt there was quite a contrast between the observed surface data and the lower tropospheric data!

An ice core with a layer of algae.

Ice core data taken from southern Greenland between 1998 and 2004 indicate that the northern hemisphere climate suddenly flipped from a cold to a warm state at the end of the last ice age, with dramatic changes in atmospheric circulation in as little as a single year, according to a study from the University of Copenhagen, which was just published in the journal Science.

The findings were based on dust, oxygen and hydrogen found in the Greenland ice cores going as far back as a million years ago.

There were two huge temperature spikes in the northern hemisphere at the end of the last ice age....

--The first spike occurred 14,700 years ago with a whopping 12 degree celsius (21.5 F) rise in just over 50 years!

--There was a second spike about 11,700 years ago after another cold period.

According to the report, scientists are trying to find out if such abrupt changes could be triggered by greenhouse gas emissions today.

From the Reuters article...........

We know abrupt climate change happens," said Jim White, a paleoclimatologist at the University of Colorado at Boulder in the United States, who worked on the study. "We don't know why it happens and we don't know what to look for as a first early warning."

Is this what southern Greenland looked like 400,000 years ago?

More from those Greenland ice cores............

Scientists from the University of Quebec at Montreal looked at pollen within the sediment ice cores dating back almost a million years and they indicate that Greenland was much greener than it is today with several warm periods over the million-year span. The data indicates that there was extensive fernlike vegetation about 125,000 years ago and widespread spruce forests about 400,000 years ago, which would look similar to the current day Norway.

Scientists already knew that Greenland had a warmer past, but the ice-core data tells them that past climate warming on the Greenland ice sheet was much greater than previously believed, according to the Canwest news service article.

The study, published in the journal Science, does indicate that it did take a 20,000 year warm period to melt back the ice sheet enough to allow the spruce forest to grow over southern Greenland, but paleoclimatologist and co-author Alexander Wolfe notes that these warm spells occurred with greenhouse gas emissions 30% lower than they are today.

The latest MSU/AMSU lower tropospheric temperature anomalies for June have been released. The temperature data is obtained by microwave sounding units on NOAA satellites. The global land/sea temperature anomaly for June (covers from 70 south latitude to 82.5 north latitude) was +0.035 K. By the way, the reading for May was -0.083 K.

Here is the MSU/AMSU lower tropospheric anomaly map for June 2008. The reds and yellows indicate above normal temperatures, while the blues and purples indicate below normal temperatures for the lower troposphere (lowest 5 miles of the atmosphere)......

Here is the image from June 2007.......

Here is the image from 20 years ago (June 1988)......

Here is a graph of the MSU/AMSU lower tropospheric temperature anomalies since 1979. Note: The trend is still upward (warming) through the period at a rate of 0.171 K/decade.

Acknowledgment:
MSU data and graphics are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

Scientists working at the McCall Glacier in the Arctic National Wildlife Refuge recently pulled a 150-meter ice core. This is the longest ice core extracted from an Arctic glacier in the United States. According to the ScienceDaily article, the core spans the entire depth of the glacier (about 1.5 football fields) and could cover 200 years of climate history in the region. The scientists are hoping that the climate record will extend as far back as the Little Ice Age. The team will begin to study this ice core this fall in Alaska. Hopefully, we will get some solid information out of that by next year.

-----------------------------------------------

More June Global Temperature data

By the way, I just saw the June global temperature anomaly from the Goddard Institute for Space Studies) GISS, which uses met station data. The June temperature anomaly was +.26 C or +.47 F, making the month the closest to normal since July of 2004, based on the GISS records since 1880. Also, so far this year the globe is running at +.44 C or +.79 F. The National Climatic Data Center will have more on this very soon.

I just read in his blog that Roger Pielke Sr. says that there is a significant warm bias (nighttime temperatures) that is not accounted for by the IPCC and their global temperature trend assessments. I would assume he is talking about the increase in urbanization (the heat island effect, which is most pronounced at night).

The National Climatic Data Center just released their global temperature analysis for June 2008. The combined global land/sea temperature was eighth warmest June on record since 1880, based on the Smith/Reynolds method. The temperature anomaly was +0.48 C (+0.86 F). The greatest warming, based on the image below was over northern Russia.

Also notice how the greater warming matches fairly well with the June 500 mb height anomaly map shown below (basically shows the mean upper-level weather pattern for the month with ridges (warm/dry aloft) and troughs (cool/moist aloft).

Also, according to the NCDC, the year (Jan-Jun 2008) is running 0.44 C (0.79 F) above normal, putting it at the 9th warmest for the period.

Other sources

The University of Alabama in Huntsville (UAH) satellite derived global temperature anomaly for June was -0.11 C or -0.20 F, making June 2008 the 9th coolest on record since 1979. The decadal trend was still slightly upward however, at +0.09 C a decade.

The Remote Sensing Systems (RSS) satellite derived data put June 2008 as the 13th coolest on their record going back to 1979. The anomaly was +0.03 C or +0.05 F. The trend was +0.15 C per decade.

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Sea Ice for June

The Northern Hemispheric sea ice extent was the third least on record for the month of June, putting it behind 2006 and 2005. The records go back to 1979.

The Southern Hemispheric sea ice extent was the second largest for June, putting it only behind 1979.

A North Dakota State University student's discovery of tiny fossils in East Antarctica indicates that much of that continent was a much warmer place many millions of years ago.

What a part of Antarctica might have looked like 70 million years ago. Courtesy National Science Foundation.

The fossils were small crustaceans called ostracods, which dated back to 14 million years ago. According to the LiveScience report, ostracods could never survive in the the current Antarctic climate. In order for them to survive, it probably had to be about 30 degrees F. (17 C) warmer on average. These fossils are probably the last remnants of a warmer Antarctica, before the massive cool down set in. The scientists believe that this find will help them better understand the effects of global warming.

This warmer period started to end when the first continent-sized ice sheets began appearing on Antarctica around 34 million years ago, around the end of the Eocene epoch. These ice sheets expanded and contracted until around 14 million years ago, during the Miocene epoch, when a dramatic cooling took place and transformed the tundra into an environment "that today looks like Mars," co-author David Marchant told LiveScience.

National Geographic News has a more in depth look at this story.

The findings were published in the Report Proceedings of the Royal Society B.

Here are the July 2008 global temperature anomalies as measured by satellite using microwave soundings. The data is provided by Remote Sensing Systems (RSS) using MSU and AMSU data. The below image shows the July temperature anomalies across the globe for the lower troposphere in degrees Kelvin. The reds and yellows indicate warmer-than-normal temperatures during the month of July, while the blues indicate cooler-than-normal conditions.

As you can see, the warmest temperatures compared to normal were found over central South America. Other above-normal areas included Atlantic Canada and eastern Russia.

Temperatures were clearly below-normal over Alaska and the Yukon Territory, aso over the far southern oceans.

Here are some specific numbers (temperature anomalies) for July.....

Global land and sea combined: +0.147 degrees Kelvin, making it the warmest month compared to normal since October of 2007, but still cooler than the past three July's.
Northern hemisphere: +0.258 K
Southern hemisphere: +0.031 K
Continental U.S.: +0.340 K

Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

The National Climatic Data Center (NCDC) has just released their offical global temperature anomaly data for July, 2008.

According to the NCDC, the combined global land and sea surface temperature anomaly for the month of July was +0.49 Celsius or +0.88 F. This makes July, 2008 the fifth warmest July on record, going back to 1880. The results were based on the Smith & Reynolds temperature anomaly analysis.

Here is our favorite dot map. Once again, the reds far outnumber the blues.

Here is the updated July land/ocean surface temperature anomaly graph going back to 1880. Smith and Reynolds analysis.

The below image shows the average sea surface temperature anomalies during a week period in the middle of July.

The below image shows the average sea surface temperatures across the globe last week. Can you see any changes?

By the way, the University of Alabama at Huntsville (UAH) lower tropospheric temperature anomaly for the globe was +0.06 C/ +0.11 F, making this past July the 15th warmest over the past 30 years based on this particular satellite measurement. Keep in mind, the Smith and Reynolds analysis takes into account record that go back 128 years.

A closeup of a stalagmite. Image courtesy of NOAA.

A West Virginia cave stalagmite has provided the most detailed geological record to date on climate cycles in eastern North America over the past 7,000 years, according to a ScienceDaily article.

Gregory Springer, a geologist from Ohio University and his team examined the trace metal strontium in the stalagmite. The stalagmite was able to preserve climate conditions averaged over periods as brief as a few years.

Through their study of the stalagmite, the team determined that there were 7 major drought periods during the Holocene era, which started about 10,000 years ago.

"This really nails down the idea of solar influence on continental drought," said Springer.

Geologist Gerald Bond suggested that every 1,500 years, weak solar activity caused by fluctuations in the sun's magnetic fields cools the North Atlantic Ocean and creates more icebergs and ice rafting, or the movement of sediment to ocean floors. The data from this study is consistent with the Bond events, which showed the connection between weak solar activity and ice rafting, according to the researchers.

Though modern records show that a cooling North Atlantic Ocean actually increases moisture and precipitation, the historic climate events were different, Springer said. In the past, the tropical regions of the Atlantic Ocean also grew colder, creating a drier climate and prompting the series of droughts, he explained.

The climate record found in the stalagmite suggests that North America could face another major drought in the next 500 to 1,000 years, but according to Springer, global warming could offset the cycle.

"Global warming will leave things like this in the dust. The natural oscillations here are nothing like what we would expect to see with global warming," he said

The findings of this study were posted in the Journal of Geophysical Research Letters.

A high resolution satellite image of Greenland.

Researchers from the University of Bristol in England have determined that the only thing that can explain the transition from a mostly ice-free Greenland 3 million years ago to the thick, ice-covered land mass that we see today is a drop in atmospheric CO2 (carbon dioxide).

According to the University of Bristol press release, 3 million years ago there was a notable increase in rock/debris on the ocean floor surrounding Greenland. The rocks could not have gotten there until icebergs started to form and transport them, which tells the scientists that the transition started around 3 million years ago.

Using climate and ice-sheet modeling, the researchers showed that the dominant cause of the Greenland glacification was the fall from high atmospheric CO2 levels to levels closer to that of pre-industrial times. Today, atmospheric CO2 levels are approaching levels that existed while Greenland was mosly ice-free.

The one question that scientists do not know the answer to is why was there a sudden drop in atmospheric CO2 three million years ago?

Here is the latest Remote Sensing Systems global temperature anomaly image for August, using microwave sounding units mounted on NOAA satellites, which measures the temperature of the lower troposphere.

August 2008.

Observations.....

1. Well above the 1979-1998 mean from Hudson Bay, Canada to west of Greenland and also over northern Siberia.
2. Cool compared to normal once again over Alaska and also over Australia.

For fun comparison, here is the image from August, 1998 (Strong El Nino year).

And August, 1988 (That was a very hot/dry summer in the Eastern U.S. as I recall)

Actual statistics for August, 2008

Global land/sea temperature anomaly: +0.146 K

Northern Hemispheric temperature anomaly: +0.315 K

Arctic region temperature anomaly (60N to 82.5 N): +0.935 K

Year so far globally.......+0.041 K by my calculations

Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com

---------------------------------------------

Update (UAH data)...................

The University of Alabama at Huntsville has posted their latest global temperature anomaly map for August. These are measured against the 20-year average from 1979-1998.

UAH also gathers their data through microwave sounding units on NOAA satellites, but their version covers more of the polar regions compared to RSS.

Here are the UAH temperature anomaly results for August, but they are still preliminary.

Global: -0.01 C or -0.02 F
Northern Hemisphere: +0.17 C or +0.31 F
Southern Hemisphere: -).19 C or -0.34 F

Researchers previously associated with the famous and controversial "Hockey stick" temperature diagram have determined that the last decade ending in 2006 was the warmest such period in the Northern Hemisphere for at least the last 1,300 years and possibly longer.

The research team utilized a much wider variety of sources compared to the "Hockey stick" study, which led to a congressional investigation in 2005. In addition to tree rings, the team also looked at sediments, stalactites and stalagmites, which in their opinion provides much more reliable conclusions.

"We sort of removed that asterisk," because the new study's conclusion didn't depend as much on one kind of data, said Michael Mann, director of Penn State's Earth System Science Center.

The decade ending in 2006 in the Northern Hemisphere was a bit more than .5 degree F warmer than the decade-long average dating back 1,300 to 1,700 years.

According to the Arizona Daily Star article, the paper is "one brick in the wall" of the case for saying that human-induced causes such as greenhouse-gas emissions are raising temperatures, said Malcolm Hughes, a dendrochronologist at the UA's Laboratory of Tree-Ring Research.

The study will be published on September 9th in the Proceedings of The National Academy of Sciences. It was authored by Malcolm Hughes, a dendrochronologist at the University of Arizona.

The is a short summary of the study and results on the right side of the Arizona Star article in the grey box.

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Update

Steve McIntyre from climate audit has a detailed critique of this study. Here is the link.

The National Climatic Data Center just released the global temperature data for this past August and the boreal summer (Jun-Aug).

According to the Smith and Reynolds temperature analysis, the combined land/sea global temperature anomaly for August 2008 was 10th warmest on record (tied with 1995).

The land/sea global temperature anomaly for the boreal summer (June/July/Aug) was 9th warmest on record. Records for both go back to 1880.

A West Antarctic Ice Core.

Geo-scientists from the Oregon State University recently analyzed West Antarctic ice core samples taken in the 1960's and ocean deposits going back 20,000 to 100,000 years ago and found some interesting results, according to Environmental Research letters.

The ice samples were carefully crushed, releasing gases from bubbles that were frozen within the ice cores. The gas samples were then tested to measure the levels of carbon dioxide (CO2) in each one.

The geo-scientists then compared the CO2 levels from the samples with climate data from Greenland and Antarctica that reflected the approximate temperatures when the gases were trapped. The samples were also compared with ocean sediments, according to ScienceDaily.

"The most interesting findings are firstly that atmospheric carbon dioxide is strongly correlated with Antarctic temperature and secondly that it begins to increase a few thousand years prior to large abrupt warming events in Greenland," researchers Jinho Ahn and Edward Brook told environmentalresearchweb. "We also see some links between increases in carbon dioxide and changes in ocean circulation that might release carbon dioxide from the deep ocean."

Remote Sensing Systems (RSS) just released their global temperature anomalies for September. RSS uses microwave instruments on satellites to measure the temperatures in the lower troposphere (lowest 7-12 miles of the atmosphere). Here is an image showing the global temperature anomalies for September 2008.

My first impression of the image is that it looks fairly normal overall, but here are the actual numbers.............

Global Land and Sea temperature anomalies for September:

Globally (70 degrees south through 82.5 degrees north latitude): +0.211 Kelvin

Northern Hemisphere: +0.290 K

Southern Hemisphere: +0.129 K

Continental United States: -0.147 K

Arctic Polar region (60 degrees north through 82.5 degrees north): +0.942 K
Note: The last time this Arctic Polar region was below normal for a month was in
April of 2006 and then again in December of 2004.

You can see the complete RSS data set right here.

Acknowledgement:
MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

The University of Alabama at Huntsville released their September 2008 temperature anomaly data for the lower troposphere (lowest ~ 8-12 miles of the atmosphere and a fairly similar method to the RSS data that I posted a couple days ago).

Here are the September temperature anomaly results.......

Global: +0.161 K

Northern Hemisphere: +0.219 K

Southern Hemisphere: +0.102 K

The past 12 months globally: +0.044 K

The decadal trend is slightly upward at +0.128 K

I will post the NCDC results when we get them, which is usually around mid-month.

A plot of global land/sea September temperature anomalies going back to 1880.

The National Climatic Data Center has just released the September temperature anomalies for the globe. Globally, September 2008 was the ninth warmest on record.

Records go back to 1880 and the temperature data is measured against the 1961-1990 mean. The data is based on the Smith and Reynolds analysis. Here are the September numbers.......

Global (land/sea combined): +0.44 C (+0.79 F)

Northern Hemisphere: +0.48 C (+0.86 F)

Southern Hemisphere: +0.40 C (+0.72 F)

By the way, the El Nino Southern Oscillation (ENSO) was basically neutral for September.

Here is our favorite dot map, the red's dominate again.

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Compare these results to the Microwave temperature data for the lower troposphere (lowest 8 km/5 miles) as retrieved by satellite......

University of Alabama at Huntsville (UAH): +0.16 C

Remote Sensing Systems (RSS): +0.21 C

The Vaughn Lewis Glacier, Juneau Icefield. Image courtesy of the USGS.

A few of our commentators directed me to this Alaska story, which is related to a story I blogged about on October 8th.......

The Anchorage Daily News posted an interesting story a couple of days ago about the impact of the 2007-2008 winter on some of the glaciers across the state.

High snowfall during the winter followed by a cool summer resulted in the largest buildup of snow on the Juneau Icefield since 1946. It was a similar situation on a lot of other glaciers as well, according to the article.

"It's been a long time on most glaciers where they've actually had positive mass balance," said Bruce Molina, a glaciologist from the U.S. Geological Survey.

Mass balance is the difference between how much snow falls every winter and how much snow fades away each summer. For most Alaska glaciers, the summer snow loss has for decades exceeded the winter snowfall.

One cool summer that leaves 20 feet of new snow still sitting atop glaciers come the start of the next winter is no big deal, Molnia said.

Ten summers like that?

Well, that might mark the start of something like the Little Ice Age.

Climate is constantly shifting. And even if the past year was a signal of a changing future, Molnia said, it would still take decades to make itself noticeable in Alaska's glaciers.

Remote Sensing Systems (RSS) has released their global temperature data for October 2008.

RSS measures the global temperatures using microwave sounding data from satellites. Here are the global numbers for the month of October, which ended up slightly above-normal for temperature in the lower troposphere (TLT).....

October 2008 global (land/sea) anomaly: +0.181 Kelvin.

October 2008 northern hemisphere anomaly: +0.283 K.

October 2008 southern hemisphere anomaly: +0.075 K

October 2008 continental U.S. anomaly: -0.135 K

Below is the RSS (TLT) global temperature anomaly map for October 2008. Reds are warm anomalies, while the darker blues are cold anomalies.

For fun comparison this is the same map from October 2007.

October 1998. (strong El Nino first half of the year)

And finally October 1988.

The graph shown below plots all the RSS TLT's from 1979 to current with the trend.

As you can see, the time interval of the most recent cooling is still not long enough in time to have noticeable impact on the overall trend of +0.158 K per decade, just like it wasn't with the short duration spike in warming back in 1998.

Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

A new study from Cornell University, which by the way has a beautiful campus, has determined that recent decades have experienced the most significant climate change since the beginning of human civilized societies (~5,000 years ago).

According to Dr. Charles Greene, an oceanographer and lead author of the study, the unprecedented warming has caused dramatic ecosystem shifts as far south as North Carolina.

During the past 50 years or so, melting ice sheets and glaciers have periodically released cold, low salinity amounts of water into the North Atlantic, according to the ScienceDaily article.

To their surprise, the researchers found that many northern species have moved southward, which counters the popular idea that southern species would move northward during the warming.

There is a nice graphic in the article which shows the path of the cold, low salinity water from the Arctic to the Northeast coast.

A new technique in determining ancient rainfall appears to support some historians views that the fall of the Roman and Byzantine Empires was partly caused by climate change, and more specifically drought, according to the ABC News article.

John Valley of the University of Wisconsin-Madison and collegues studied stalactites from a cave near Jerusalem.

Using a new instrument called an ion microprobe, Valley and his team were able to see much more finer detail within the "rings" of the stalactites, which basically contain a historical record of rainfall climate in the region from 200 B.C to 1100 A.D.

The ion microprobe allows the team to break down the stalactite data by a single year, or even separate seasons, as opposed to centuries.

"The advantage of the ion microprobe is it allows us to analyze samples that are a million to a billion times smaller than we could in the past," said Valley.

The new tool allowed the team to construct the climate record year by year during the time the Roman and Byzantine empires were struggling to survive.

Findings

The team determined that there was a gradual reduction in rainfall during the period all the way back to 200 BC, which supports, but does not yet prove that drought from climate change was partially responsible for the fall of these empires, as some historians have said.

Remote Sensing Systems (RSS) and the University of Alabama at Huntsville (UAH) recently released their November temperature data for the globe. This temperature data is retrieved by microwave sounding units that are mounted on satellites.The anomalies that I am showing cover the lower troposhere.

Overall, November was a warmer month globally compared to normal.

RSS temperature anomalies for November

RSS global temperature anomaly (70 S to 82.5 N) for November: +0.216 K

RSS Continental U.S. temperature anomaly for November: +0.206 K

RSS Northern Hemisphere temperature anomaly for November: +0.231 K

RSS Southern Hemisphere temperature anomaly for November: +0.200 K

There has been a slight upward trend in global anomalies since June of this year on the RSS, and November is the warmest compared to normal since October of 2007. This trend may be partially due to the demise of the La Nina earlier in the year.

University of Alabama at Huntsville (UAH) preliminary temperature anomaly data for November of 2008.

UAH global temperature anomaly for November 2008: +0.25 C

UAH Northern Hemisphere temperature anomaly for November 2008: +0.34 C

UAH Southern Hemisphere temperature anomaly for November 2008: +0.17 C

Acknowledgements...........
MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com. Link.

Temperature data and graphic courtesy of the University of Alabama at Huntsville. Link.

William Brennan of NOAA.

The National Oceanic and Atmospheric Administrations (NOAA) acting administrator William Brennan said that the North American continent as a whole is warming, mostly as a result of the energy sources we are using. According to the AP article, Brennan made this statement at a briefing on the nation's climate since 1951.

But, according to Martin Hoerling of NOAA's Earth System Research Laboratory, no change in temperature has occurred since 1951 in the center of the U.S., in what Hoerling describes as sort of a "warming hole".

Overall, surface temperatures over the United States have increased 1.6 F since 1951, with most of that warming taking place over the past 30 years.

The NOAA officials also noted that November 2008 was 2.0 degrees above normal for the contiguous U.S. and that this past month was the warmest November on record in the western states. Much of that can be attributed to the large, persistent upper-level ridge of high pressure which covered the region during most of November.

I decided to have a little fun today with the GISS temperature anomaly and trend temperature plot maps that you can generate on their site. The latest GISS (Goddard Institute for Space Studies), HadCRU and NCDC global temperature anomalies for November and the annual period from December to November were just released.

All three are pretty consistent in showing that the latest December through November annual period was just over .40 C (.72 F) above normal globally. Here are the specifics for the Dec 2007 to Nov 2008 period.......

GISS +.43 C (+.77 F)
NCDC +.47 C (+.85 F)
HadCRU +.42 C (+.76 F)

Looking specifically at the GISS data, it looks like the Dec 2007 to Nov 2008 annual period was the coolest since the year 2000, but it still ends up making the all-time (going back to 1880) top ten warmest list, coming in at 9th place. By the way, the month of November global land/sea GISS anomaly was +.58 C or (.77 F).

Here are some of the maps I was able to create from the GISS site. The first ones show temperature anomalies against the base period from 1951-1980. The last two show the overall trend in annual temperature. The first one is for this century and the second goes back to 1930.

November 2008 temperature anomalies (GISS)

Dec 2007 to Nov 2008 temperature anomalies (GISS)

Global temperature trends from 2000 through Nov 2008

Global temperature trends from 1930 through Nov 2008

(I put this in since a number of commentators on this blog get angry when they leave out the warmer decade of the 1930s)

A rice paddy in India. Image courtesy of Wikipedia.

Researchers from the University of Wisconsin-Madison, using supercomputers and advanced climate models have hypothesised that human actions started causing global warming between 5,000 and 8,000 years ago.

According to the article from the Milwaukee Journal Sentinel, the implementation of agriculture in Asia and widespread deforestation in Europe was the main cause. Specifically, the introduction of rice cultivation and large scale tree removal led to a significant rise in carbon dioxide and methane levels into the atmosphere.

The UW team lead by Steve Vavrus, a climatologist from the University of Wisconsin's Center for Climatic research also think that the build up of greenhouse gases over thousands of years has prevented the start of a new glacial age. I posted a blog last month (November 17th) that talks about this as well.

The National Oceanic and Atmospheric Administration (NOAA) led a recent scientific assessment which studied the likelihood and extent to which human activity or natural variations have driven surface warming and precipitation in North America over the past 50 years.

Here is what they found, according to the ScienceDaily article............

Changes in sea-surface temperature patterns likely played an important role in determining differences in United States regional temperature trends and large precipitation swings.

These regional differences in sea-surface temperature trends can be either natural or human-caused, but the assessment also found that an increase in greenhouse gases is likely responsible for more than half of the average continental warming of 1.6 F during the past 50 years.

"Using reanalysis and attribution methods we can now say with more confidence what’s driving some of the extreme climate conditions of the past few years: whether it’s global warming, El Nino, La Nina, or some other pattern," said NOAA scientist Martin Hoerling.

Remote Sensing Systems (RSS) has released their global temperature anomaly data for the lower troposphere.

The temperature data is retrieved by microwave sounding units on board satellites.

Brightness temperature anomalies are the difference between the monthly brightness temperatures and the average value for that month (found by averaging that month from 1979 through 1998).

Looking at the above image a couple of things stick out......

1. The unusual cold over the northern U.S. and most of Canada, along with northern Asia.
2. The unusual warmth over eastern Europe.
3. The pocket of warm anomalies over the northern and western Pacific, which is indicative of the ongoing "cool" phase of the Pacific Decadal Oscillation (PDO).

December numerical temperature data for the lower troposhere from RSS.

Global land and sea combined temperature anomaly: +.174 K
Northern Hemisphere anomaly: +.272 K
Southern Hemisphere anomaly: +.072 K
United States anomaly: -.609 K

Also, despite the drop in global temperature anomalies for the lower troposphere over the past 1.5 years, the overall decadal trend is still slightly upward at +.157 K.

The University of Alabama at Huntsville December data for the lower troposhere has not been released yet, but their overall decadal trend is +.128 K.

Here is an RSS TLT brightness image showing the anomalies from north to south across the globe going back to 1979. You can see that most of the warming over the past several years has been in the far northern latitudes. The 1998 El Nino warming (warm reds) near the equatorial latitudes shows up nicely as does the most recent La Nina (cooler blues).

---------------------
Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

The University of Alabama at Huntsville (UAH) released their preliminary global temperature data for December 2008.

UAH data is retrieved by microwave sounding units on board satellites. The sounding units calculate the temperature of the lower troposphere from the surface up to 8 km above sea level.

December results

Global temperature anomaly: +0.18 C or +0.32 F above the 20-year average.
This makes December 2008 the 11th warmest December in the past 31 years.

Northern Hemisphere anomaly: +0.41 C or +0.74 F.
This makes December 2008 the 5th warmest December in the past 31 years for
the Northern Hemisphere.

Southern Hemisphere anomaly: -0.05 C or -0.09 F.
This makes December 2008 the 10th coolest December in the past 31 years for
the Southern Hemisphere.

By the way, UAH revised their November global temperature anomaly to +0.25 C.

Here is a map showing the December anomalies throughout the world, courtesy of the UAH
temperature site.

A few more stats from UAH

--Since 1978, the Northern Hemisphere has warmed more than 3 times as fast as the
Southern Hemisphere.

--2008 was the coolest year globaly since 2000, but UAH states that this was influenced by the cooling effect of La Nina.

--The global temperature trend since 1978 is increasing at a rate of 0.13 C per decade.

Remote Sensing Systems (RSS) has released their lower tropospheric temperature anomaly data (based on microwave sounding data on board satellites) for the month of January. I think many of you who live in eastern North America or western Europe will be very surprised to hear that the month of January as a whole was clearly warmer-than-normal when you take most of the globe into account.

The image below, courtesy of RSS, shows the January global temperature anomalies for the lower troposphere (TLT).

--Notice the large areas of below-normal temperatures over western Europe and eastern North America.

--Pockets of much-above normal temperatures were located in the western Pacific, the western U.S. and north Africa.

------------

Here are the specific temperature anomalies for January from RSS.........

Global anomaly (70 south to 82.5 north): +.322 K
Note: the last time the RSS TLT global anomaly was that high was back in August of 2007.

Northern Hemisphere (0 to 82.5 north): +.449 K

Southern Hemisphere (70 south to 0): +.190 K

United States: +.358 K
Note: The last time the anomaly was this high was back in Nov 2007. Hard to believe if you live in the East. Also, this January anomaly was about a full degree warmer versus the December 2008 anomaly.

----------------

Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com

Updated temperature anomaly graphs courtesy of the Goddard Institute for Space Studies (GISS).........

A global snapshot of the January temperature anomalies. Reds and browns are above normal temperatures and the blues are colder than normal.

GISS plot of the anomalies by zone for Jan 2009. You can clearly see that the greatest warming has been in the far northern hemisphere.

The latest plot of the GISS land/ocean temperature anomaly since 1880. The anomalies are calculated against the 1951-1980 mean.

Here's a break down the GISS lnd/ocean plot of anomalies by hemisphere.

GISS temperature anomaly plot for the United States.

----------------------------------------

GISS plot the monthly mean sea-surface temperature anomalies and at the bottom the Nino 3.4 region. Higher reds in the Nino 3.4 indicate El Nino conditions, while the lower blues indicate La Nina conditions. At present, we have weak La Nina conditions going on in the equatorial Pacific.

--------------------------

All the January temperature data for the globe has now been released from the different sources.

All the sources confirm that January was indeed warmer compared to normal on a global scale, but to varying degrees. Here are the temperature anomaly details.........

National Climatic Data Center (NCDC) using the Smith and Reynolds method......

---Global land/ocean combined: +0.53 C or + 0.95 F, making it the 7th warmest January since 1880.

--Northern hemisphere: +0.60 C or + 1.08 F, making it the 7th warmest January.

--Southern hemisphere: +0.46 C or +0.83 F, making it the 7th warmest January.

Goddard Institute for Space Studies (GISS) method......

--Global land/ocean combined: +0.52 C or + 0.94 F

University of Alabama at Huntsville (UAH) method, which measures the lower troposphere using microwave sounding units on board satellites....

--Global land/ocean: +.30 C or +0.54 F

Remote Sensing Systems (RSS) method, which also measures the lower troposphere using microwave sounding units on board satellites....

--Global land/ocean: +0.32 C or +0.58 F

Remote Sensing Systems (RSS) has released their global temperature data for the month of February.

RSS uses microwave sounding data on board satellites to measure the global temperatures at different levels of the earth's atmosphere.

Here is the February temperature anomaly map for the lower troposphere.....

A couple of observations from the above image.......

1. Note the strong negative (cold) anomalies over Siberia.
2. Note the strong positive (warm) anomalies over southeast Asia, the southern U.S. Plains and Mexico.
3. You can also see the strong positive anomaly over the northwest Pacific, while the Pacific waters just off the North America coast are below normal. This is a classic signature of the cool phase of the Pacific Decadal Oscillation (PDO).

Here are the official RSS lower troposhere temperature anomalies for February.

Global (-70S to 82.5 N): +.230K

U.S.: +.438K

Northern Hemisphere: +.391K

Southern Hemisphere: +.062K

-----------------------------

I looked at the RSS lower troposheric temperature data since 2007 and noted the distinct downward trend in temperature between September 2007 and June 2008. The trend in temperatures since June of 2008 has been clearly upward.

I wanted to see how this matched up with the recent La Nina. According to the NOAA ENSO site, there were official La Nina conditions (based on their strict criteria) between the three month period of Aug/Sep/Oct 2007 and Apr/May/Jun of 2008, which happens to match up almost exactly with the RSS cooling trend stated in the previous paragraph.

It does appear that La Nina conditions did recently return (though not officially as the monthly criteria has not been met as of yet). NOAA predicts that La Nina conditions will weaken through the spring. Brett (still on vacation and sick as a dog).

--------------------
Acknowledgement

MSU/AMSU data are produced by Remote Sensing Systems and sponsored by the NOAA Climate and Global Change Program. Data are available at www.remss.com.

The National Climatic Data Center (NCDC) released their global temperature anomaly data for February. The NCDC uses the blended land and ocean dataset developed by Smith and Reynolds.

Here is the NCDC dot map (a fan favorite!)

Overall, February 2009 was the 9th warmest February on record, based on 130 years of record keeping.