An increase in moisture generates more clouds, which blocks UV and causes negative feedback.

The inability of climate models to simulate clouds is one of the primary reasons they aren't reliable.

Oh please.

Let me see if I have this right.
Warmer air can hold more moisture.
Since there is more moisture in the air, it is warmer.
So human induced CO2 must be the cause.

What kind of science is that?

I don't believe climate scientists really know whether increased moisture in the atmosphere is a positive or a negative feedback. It depends on whether that extra moisture increases the cloud cover or not, and that's something that's still not handled correctly by the current climate models.

Reply: That is a valid concern Tom as I can personally attest to cloud cover issues by the models in my daily forecasting. Brett

I wonder if NOAA will start preannouncing records soon? Their climate models have been proven reliable and there is really no reason for them to wait to the end of the period to announce that this (month/year/decade) was the warmest in history.

In response to some comments, as a climate scientist: Yes, more moisture in the air can increase cloud cover, however, not all cloud cover has a cooling effect. High clouds have a warming effect actually because they still allow radiation to reach the surface, but they themselves radiate out to space at a very cold temperature because of their elevation. Thus, the net down is greater than the net up.

Additionally, in response to Boondocks: warmer air holds more moisture, yes. Water vapor is a greenhouse gas, similar to CO2. In fact, water vapor is the strongest and most prevalent greenhouse gas. Without it, our planet would be inhabitable. Solar radiation balances alone would leave our planet 33 C cooler, thus water vapor is the important balancing mechanism. Thus, more water vapor = more greenhouse warming, which in turn leads to more water vapor.

I've been reading this blog for quite some time, and I am disheartened by the negative bent it has toward climate change. This post, for example, is confusing to someone who is unfamiliar with atm. physics. Present all the facts or don't present anything at all.

...natural variability in climate just can't explain this moisture change.

Let me get this straight, if exactly the same moisture profiles and associated variables did have a natural cause, then these computer models would not give the same answer. Have I got that right?

Verily, these climate models are shiftie beasties.

natural variability in climate just can't explain this moisture change. The most plausible explanation is that it's due to the human-caused increase in greenhouse gases.

i.e. the author has no clue what is causing this.

NASA Science News for September 18, 2007

Last week in Boulder, Colorado, scientists converged on the "Living With A Star" workshop to share the latest research in solar physics. At one point, nearly 200 participants sat slack-jawed as they watched a new movie recorded by Japan's Hinode spacecraft showing a sunspot emerging from the depths of the sun. The newborn spot resembled nothing less than a swimming planet-sized trilobite.

Ref: A trilobite is an extinct 3 lobed marine arthropod of the Paleozoic era.

Goes to show you, what scientists thought they knew about sun spots was not actually correct. The study of science is always evolving. Amazing!

See for yourself.

http://science.nasa.gov/headlines/y2007/18sep_trilobite.htm?list1040802

I don't think anybody has any idea of how these awesome video clips relate to global climate change, but I share Rich's appreciation for the dramatic video.

Wow!

High clouds have a warming effect actually because they still allow radiation to reach the surface, but they themselves radiate out to space at a very cold temperature because of their elevation. Thus, the net down is greater than the net up.

Mike,

The effect you are describing (high clouds causing warming) is due mainly to the fact that they absorb and radiate some IR downwards at night, which a clear sky won't do. High clouds during the day tend to cool temperatures at the surface - as every skier knows. Once a high cloud comes over, temperatures can cool substantially on the slopes. The cloud goes away and it warms up right away.

In �Inconvenient Truth� is a chart with several instances where the temperature and CO2 go up �together� and then down �together�. What we are not told is that the temperature goes up first and the CO2 follows. If the increase in CO2 caused a significant increase in the �greenhouse effect� the temperature would go even higher, causing more CO2 and more water vapor, which would raise the temperature even more - culminating in a heating death spiral. It didn�t happen. Eventually, the temperature went back down and the CO2 concentration followed.

Mike,

I'm not familiar with solar radiation balances, what is that exactly?

This article states that the additional .41 kg per meter squared is caused by the additional warming caused by CO2, CH4, etc, when the strongest evidence to support that is a "very highly likely" that stems from these scientists' belief that natural influences cannot be the cause.

I'd like to know how an additional 2 Watts per second per meter squared increase in solar irradiance can be disregarded when there are nearly 254 billion square meters facing the Sun at all times? That energy must go somewhere. A .15% increase to 300 Kelvin is .45 Kelvin.

With your experience, what would you say is the cause for the one degree increase we have seen since the end of the Little Ice Age?

Regards,

Steve

Mike,
High clouds can act as both as a negative or positive feedback mechanism. Durng daylight hours, even high level cirrus stratus will decrease the amount of insolation. During the night, cirrus can also dampen the amount of radiative cooling in some situtations. Of course, you may not always notice this, as in the mid-latitudes cirrus stratus normally preceeds frontal systems. In many cases strong low level warm air advection will raise the ambient air temperature despite the presence of thick overcast skies.

Where cirrus stratus could have a big effect is in the tropics, where insolation is at its strongest. BTW, it is the tropics, where, because of its constant warm temp, there is also the greatest density of water vapor (as measured in grams of WV/ kilogram of dry air). It is the tropics that not only have the greatest amount of insolation (as measured in Watts per/sq metre), but also the greatest amount of GHGs. If there was to be an increase in high level cirrus or even mid level alto-stratus, there would be an attendent "cooling" of tropical air masses.

Hi Guys,

Vapor in rain out. hhmmm
Well it looks like this ones got some problems. Please see the link.

http://climatesci.colorado.edu/2007/04/05/evaporation-is-equal-to-precipitation-on-the-global-scale-implications-to-the-conclusion-on-a-claimed-increase-of-atmospheric-water-vapor/

Mike:

I believe you have focused on my lead-in and not my point. Which is, pointing out one indicator that the atmosphere is warming does not demonstrate that anthropogenic CO2 is the impetus of that warming.

Brookline(mass)Tom,

It wasn't the clips themselves that relate to global climate silly, but rather the fact that scientists are still learning about that big fireball in the sky, which effects global climate. Up until 6 moths ago, we didn't have as much detailed information and 3-d imagery of the sun as we do now. They were not completely accurate with the solar physics aspect behind the theory of sun spot generation. Hence the reason I stated that the very science used in understanding not only the sun but our own planet is always evolving. Sorry you couldn't connect the dots. Don't stereotype everyone in the same category as you. I am sure some will see the relevance.

Did anyone see or hear anything about the meteorite coming that landed in Peru before it happened? We didn't even hear a peep about something so obvious as an incoming meteorite. But in our own arrogance, we think that we have everything figured out, don't we? We are still learning is the point. It may be difficult for someone such as yourself to accept the fact that maybe we don't know everything. The truth is Tom, we will never know everything, for sure, until we die. This is why we call some of OUR logical explanations, theories.

Go Pats ;)

JP and Patrick Henry,

High clouds do block radiation, however, because they are typically above 500 mb they are very cold (as the atmosphere cools as you increase in height). Now, assume for a moment that the cirrus clouds are approx. 230K. This means that they are radiating out to space [ sigma*(230)^4 ] Watts/m2. Now, if the cloud weren't there, then space would only see the Earth which is much warmer, say 290K. That means the cloud is radiating out sigma*(60^4) W/m2 LESS radiation than Earth. Thus, the planet is giving OFF much less heat. Now, assume without the cloud that approx. 200 W/m2 of the sun's original energy made it to Earth. The presence of the cloud perhaps reduces that figure to 180 W/m2. Thus, the change in downward energy is only 20 W/m2. As you can see, simple physics explains how high clouds act to WARM the planet, no matter the time of day.

Now, Steve, just to clarify, Watts per second per square meter is not the correct term, as Watts = Joules per second. I digress. I don't understand your question. Are you saying that the sun outputs an additional 2 W/m2 than it has in the past? Or that it goes through cycles? Please clarify.

-MIke

mike,

i too am disheartended by the lack of integrity by those that claim they can predict future climatic conditions 50 years from now to within a hundredth of a degree, or as in the case of the above article, use remote sensing techniques to calculate a 2% change in global atmospheric moisture content for the past twenty years, then even worse claim without any evidence, its man's fault...to further give me the blues, is the crowd of scamsters going around profiting off these doom and gloom scare tactics at the expense of the most vulnerable...keep your chin up, little buckaroo, i just read that some real scientists are going to try and lasso the AGW LIE with a scientific integrity world conference in a couple of days, convened because of gross misrepresentations in climate modeling...here comes the real science rodeo, and AGW is in for a rough ride...have a nice sunny warm day, it will brighten your climatic outlook!!!

Also, JP, your claim that the tropics contain the highest levels of GHGs is not true. Please refer to the following plots:

http://instaar.colorado.edu/sil/images/co2rug_490px.jpg

As you can see, CO2 levels are highest in the Northern Hemisphere winter. In the Northern Hemisphere. As explained by plant respiration.

Also, JP, your claim that the tropics contain the highest levels of GHGs is not true. Please refer to the following plots:

http://instaar.colorado.edu/sil/images/co2rug_490px.jpg

As you can see, CO2 levels are highest in the Northern Hemisphere winter. In the Northern Hemisphere. As explained by plant respiration.

Page 40 of the Technical Summary of the IPCC Physical Science Basis contains the following statements.

Tropospheric water vapour is increasing (Figure TS.8). Surface specific humidity has generally increased since 1976 in close association with higher temperatures over both land and ocean. Total column water vapour has increased over the global oceans by 1.2 +- 0.3% per decade (95% confidence limits) from 1988 to 2004. The observed regional changes are consistent in pattern and amount with the changes in SST and the assumption of a near-constant relative humidity increase in water vapour mixing ratio. The additional atmospheric water vapour implies increased moisture availability for precipitation.

Upper-tropospheric water vapour is also increasing. Due to instrumental limitations, it is difficult to assess long-term changes in water vapour in the upper troposphere, where it is of radiative importance. However, the available data now show evidence for global increases in upper-tropospheric specific humidity over the past two
decades (Figure TS.8). These observations are consistent with the observed increase in temperatures and represent an important advance since the TAR. {3.4}

Chapter 9 deals with understanding and attributing climate change. It does not contain a section dealing with water vapor. However, section 9.5.4 deals with precipitation and contains the following statement.

Greenhouse gas increases are also expected to cause enhanced horizontal transport of water vapour that is expected to lead to a drying of the subtropics and parts of the tropics (Kumar et al., 2004; Neelin et al., 2006), and a further increase in precipitation in the equatorial region and at high latitudes(Emori and Brown, 2005; Held and Soden, 2006).

The truth is Tom, we will never know everything, for sure, until we die.

No doubt.

There is a staggering amount of information that we don't know about metallurgy, aerodynamics, and even basic physics. Yet most of us still get on airplanes -- even though they sometimes crash. Each time we do, we implicitly accept the reality that our "theories" about flight are reliable enough, and our knowledge about the science of flight is complete enough, that we willingly trust that we'll arrive safely at our destination. That trust is well-placed the overwhelming majority of the time.

There will, thankfully, always be new science to explore in almost any field we choose. That is why, in my opinion, it is so offensive to artificially inflate uncertainty about material that is, in fact, already settled.

As fascinating as the video is that you posted, it has no discernible relevance to the science of global climate change. Similarly, the recent Peruvian meteorite hit is fascinating -- especially because of the apparent atmospheric anomalies in the immediate area -- and still has no discernible relevance to global climate change.

Thanks for the great clip, however. It does illustrate, rather marvelously, the inspiring appeal of good solid science.

A little more of the science.

Water vapor in the atmosphere generally decreases with elevation. Above a certain elevation (the tops of clouds) the atmosphere is so cold that water vapor can not exist as anything other than ice and ice does not stay up in the atmopshere very well.

On the other hand, CO2 and CH4 are well mixed at all elevations of the atmosphere. However, there has been a generally increasing amount of CO2 and CH4 due to human causes.

What is being found, is that over time water vapor is reaching greater and greater elevations of the atmosphere. This makes sense because it is at the higher elevations where CO2 and CH4 are providing additional warming.

sammyk, perhaps you misunderstood. I'm upset that there are still so many people out there who would turn a blind eye to science and say GW isn't real. Nobody is predicting climate conditions 50 yrs from now to within a hundredth of a degree. Nor does anyone claim to know exactly what will happen. There is, however, surmountable evidence that humans are causing global climate change, and for you to say that us scientists, who are conducting REAL research, and are not gathering our "facts" from the "media", are just making it all up, is absurd, reprehensible and irresponsible. How can you say that we claim, "WITHOUT EVIDENCE" that it's man's fault. You want evidence? There is plenty of evidence. Do some research instead of listening to the views of a select few naysayers. For the benefit of science, find a reliable source for your information, instead of the media, and a weather site. Because we all know meteorologists are NOT climatologists.

Mike,

The energy balance of the atmosphere is fixed. On average, as much energy arrives as leaves every day. If this wasn't true, the temperature of the atmosphere would change dramatically.

During the day, cirrus clouds lower the temperature at the surface markedly. People who live at dry, high-altitude locations are well aware of this. Here in Colorado on a calm day with full sun, it can be quite comfortable even at temperatures well below freezing. However, a few cirrus clouds roll over and on goes the jacket. Everyone here understands this. It happens because cirrus clouds block a lot of short wave radiation.

At night, the opposite effect happens. There is little short wave radiation coming in, and some of the long wave radiation gets reflected or emitted downwards towards the ground. Nights with high clouds can be much more comfortable in the winter.

The numbers you are "assuming" above are probably incorrect if they don't match direct observation. Perhaps cirrus clouds absorb or reflect a lot more short wave radiation than you are assuming? This will cause the clouds to warm more and the surface to warm less. Your math doesn't seem to be taking this into account.

One problem I have with some climate modelers is that they seem to be very fond of math, to the exclusion of simple qualitative analysis - like watching water go down a bath or having an apple fall on their head. I have been involved with several multi-billion dollar boondoggles which could have been rescued by some simple back of the envelope calculation