This is important because scientists are concerned that unchecked global warming could cause already dry areas to get drier. (Global warming may also cause wet areas to get wetter.) Cao and Caldeira’s findings indicate that reducing atmospheric carbon dioxide could prevent droughts caused by climate change.
Via press release in Eurekalert, from Stanford, and the Carnegie Institution:
Cutting carbon dioxide helps prevent drying
Washington, D.C.—Recent climate modeling has shown that reducing the concentration of carbon dioxide in the atmosphere would give the Earth a wetter climate in the short term. New research from Carnegie Global Ecology scientists Long Cao and Ken Caldeira offers a novel explanation for why climates are wetter when atmospheric carbon dioxide (CO2) concentrations are decreasing. Their findings, published online today by Geophysical Research Letters, show that cutting carbon dioxide concentrations could help prevent droughts caused by global warming.
Cao and Caldeira’s new work shows that this precipitation increase is due to the heat-trapping property of the greenhouse gas carbon dioxide in the atmosphere. Carbon dioxide traps heat in the middle of the atmosphere. This warm air higher in the atmosphere tends to prevent the rising air motions that create thunderstorms and rainfall.
As a result, an increase in the atmospheric concentration of carbon dioxide tends to suppress precipitation. Similarly, a decrease in the atmospheric concentration of carbon dioxide tends to increase precipitation.
The results of this study show that cutting the concentration of precipitation-suppressing carbon dioxide in the atmosphere would increase global precipitation. This is important because scientists are concerned that unchecked global warming could cause already dry areas to get drier. (Global warming may also cause wet areas to get wetter.) Cao and Caldeira’s findings indicate that reducing atmospheric carbon dioxide could prevent droughts caused by climate change.
“This study shows that the climate is going to be drier on the way up and wetter on the way down,” Caldeira said, adding:”Proposals to cool the earth using geo-engineering tools to reflect sunlight back to space would not cause a similar pulse of wetness.”
The team’s work shows that carbon dioxide rapidly affects the structure of the atmosphere, causing quick changes precipitation, as well as many other aspects of Earth’s climate, well before the greenhouse gas noticeably affects temperature. These results have important implications for understanding the effects of climate change caused by carbon dioxide, as well as the potential effects of reducing atmospheric carbon dioxide concentrations.
“The direct effects of carbon dioxide on precipitation take place quickly,” said Cao. “If we could cut carbon dioxide concentrations now, we would see precipitation increase within the year, but it would take many decades for climate to cool.”
Recently, it was found that a reduction in atmospheric CO2 concentration leads to a temporary increase in global precipitation. We use the Hadley Center coupled atmosphere-ocean model, HadCM3L, to demonstrate that this precipitation increase is a consequence of precipitation sensitivity to changes in atmospheric CO2 concentrations through fast tropospheric adjustment processes. Slow ocean cooling explains the longer-term decrease in precipitation. Increased CO2 tends to suppress evaporation/precipitation whereas increased temperatures tend to increase evaporation/precipitation. When the enhanced CO2 forcing is removed, global precipitation increases temporarily, but this increase is not observed when a similar negative radiative forcing is applied as a reduction of solar intensity. Therefore, transient precipitation increase following a reduction in CO2-radiative forcing is a consequence of the specific character of CO2 forcing and is not a general feature associated with decreases in radiative forcing.
If someone will send me a copy of the paper (willis [at) surfacetemps.org) I’ll be happy to take a look.
The beauty of the paper seems to be that it describes a situation (a quick reduction in atmospheric CO2 concentration) that, as far as I know, hasn’t been observed in nature …
So usually I’d ask “Where’s the comparison of the model with the observations?” But it appears they’ve sidestepped that very neatly.
But heck, I could be wrong, it’s just a press release and an abstract. The paper may say something different.
w.
The article is the inevitable result of the “publish-or-perish” mandate for attaing tenure or promotion at a university. Like Photoshop, a model can be made to look like whatever the user wishes. These researchers know what side to be on to impress their superiors. I’ve seen it happen before, and I trust the results now no more than I did back in the days when I was a university teacher and administrator. Garbage in, garbage out–people understood that even at the beginning of the computer age, and it’s still true.
It would be so refreshing to see a study based on actual observations! Oh, wait–we have seen quite a few, and they contradict the above-mentioned “study” on just about every statement.
More of the (Un)Intended Consequences of Simplistic Linear Equations allowed to run wild. SLEs are the preferred output of Expert Brains, a belief in the ignorance of which is, per Feynman, the definition of Science.
“The direct effects of carbon dioxide on precipitation take place quickly”
So, 60 years is not quickly? I wonder what they mean by “quickly”. Maybe we need to add slowquick (or is that quickslow) to the ever expanding climate dictionary.
This report begs for the Willis treatment. I look forward to his assessment.
What is most worrisome to me are the repeated calls for some massive intervention in the global system (geo-engineering). We may find the medicine is worse than the (model predicted) disease and then we may find it impossible to undo the damage.
mmmm I get it, the same as Old Seadog above.
The West Coast of New Zealand has up to 6000 mm of rain and is clearly wet. That means it will get dryer. Most Coasters will be glad of that since they wont have to keep all the car doors open on sunny days anymore to dry them out.
The East Coast of New Zealand is often dry with droughts, So it will get wetter, ie borrow a bit of rain from the West Coast.
That is a perfect solution, since only a few years ago there was talk of running a huge pipeline from the West Coast to the East Coast to mitigate the droughts.
These models are just a great way to solve problems with a click of a mouse.
Carbon dioxide traps heat in the middle of the atmosphere. This warm air higher in the atmosphere tends to prevent the rising air motions that create thunderstorms and rainfall.
They seem to be regenerating in their model the hot spot, which has been soundly refuted by data. CO2 has been going up, the hotspot down.
Maybe it is monkeys who do the peer reviews of climate papers.
More ecostrology from ecostrologists…out to help their colleagues, the climastrologists and paleostrologists.
And this went through peer review to get into Geophysical Research Letters?
They allowed a paper that based all its logic on a model prediction of a tropospheric hot spot that has been repeatedly falsified by observations?
This puts Geophysical Research Letters somewhere below The National Enquirer.
I think these lads have the process backwards. They say –
“Carbon dioxide traps heat in the middle of the atmosphere. This warm air higher in the atmosphere tends to prevent the rising air motions that create thunderstorms and rainfall.”
At current CO2 concentrations, the ‘path length’ for nearly complete absorption in the CO2 sensitive wavelengths, is on the order of 10 to 100m. That means that virtually none of the ‘original’ emitted photons from the surface even reach the middle of the atmosphere. More CO2 means the ‘original’ photons are captured closer to the ground surface, not higher up in the ‘middle of the atmosphere’.
What then? Once captured, we are told that, rather than being re-emitted to the middle atmosphere, it is 10,000 times more likely that the CO2 will bump into an O2 or N2 molecule, and the captured photon becomes thermalized – that is, that photon will be converted to heat/kintetic energy in the other atmospheric gasses. At which point, the warm rising thermals take over and typical Lapse Rate cooling occurs.
Right off the bat…
“Recent climate modeling has shown […]”
Look – – – out – – – the – – – window – – – every – – – now – – – and – – – then.
.
.
.
(For some odd reason I keep thinking about CAGW climate science and those old chain letters where you sent a dollar to the name at the top of the list. All sorts of dire things were supposed to happen if you broke the chain. There are some who will do just about anything to keep their name at the top of the list.)
Anthony,
If I did a 2 day graph and said it was climate for all the billions of years would you be gullible to it?
Why not? It is part of the billions of years.
On a brighter note…It is a crisp -15 degrees C here and has been abnormally cold by an average of 4-5 degrees C this winter with many below 10-12 degree C days averages to previous years.
“The team’s work shows that carbon dioxide rapidly affects the structure of the atmosphere”
Does it.
Ken Caldiera in his lab, is heard crying out, “A mid troposphere hotspot, a mid troposphere hotspot – my nobel prize for a mid troposphere hotspot.”
Of course, I just made that up. Ken Caldiera never said it because he lives in a world of virtual electrons that is the world of climate models, and would never have looked at real world data. Had he done so, he would have known that this warming of the mid troposphere predicted by his models does not actually exist. He would have known that the premise of his paper is therefore false.
Too bad. A nother paper that should have been tossed in the garbage.
I think a moratorium on funding studies using climate models would be in order.
CO2 levels are not going to decrease so this is an abstract “what if” paper. One of the authors has done past work on geoengineeering, so maybe that is his motivation. Here is the abstract.
http://www.agu.org/pubs/crossref/2011/2011GL046713.shtml
It seems confusing at first. You may have to read it several times to get it. I have no idea if the results are correct, but what they are doing is not inherently illogical as some people here seem to think.
Just for anna v:
http://www.skepticalscience.com/tropospheric-hot-spot.htm
“The team’s work shows that carbon dioxide rapidly affects the structure of the atmosphere, causing quick changes precipitation, as well as many other aspects of Earth’s climate, well before the greenhouse gas noticeably affects temperature.”
Amazing. Co2 now has the ability to affect the “structure” of the atmosphere and “quickly” cause changes to all sorts of climate things…WITHOUT NOTICEABLY AFFECTING TEMPERATURE.
I wonder what physical process they envision that allows that huge mass of CO2, you know, at 380 parts per million, to change things without warming or cooling? Oh, its right there in their article. They postulate both that there will be warming caused by CO2 high in the atmosphere, AND nobody will notice it.
With apologies to Mr. A. C. Clarke.
Any sufficiently advanced total bu**sh*t is indistinguishable from science. If anyone wonders what the three *’s are, they stand for PNS.
I have here further ontological proof for AGW.
Half a bee, philosophically,
Must, ipso facto, half not be.
But half the bee has got to be
Vis a vis, its entity. D’you see?
But can a bee be said to be
Or not to be an entire bee
When half the bee is not a bee
Due to some ancient injury?
Singing…
Are they saying that CO2 causes stalled high pressure areas and what we used to call “heat inversions?” That, supposedly, is what caused the hot summer of 1980 in St. Louis and, a few years later, a similar phenomenon in Dallas. But these phenomena are few and far between. I don’t believe they occurred again in St. Louis or Dallas.
Well, just model something and see whether you make it into the IPCC report. Climate science works like a beauty contest. Millions of young wannabe climatologists prepare their paper, each one trying to find a new and innovative way CO2 yould make everything worse, and Pachauri will later decide who of them will become a famous doom-monger.
Vince Causey says:
March 26, 2011 at 5:01 am
“Ken Caldiera in his lab, is heard crying out, “A mid troposphere hotspot, a mid troposphere hotspot – my nobel prize for a mid troposphere hotspot.”
You took my very words Vince! At what point will they admit that the models just do not work? They ignored the weather balloon evidence, and other subsequent evidence that backs it up.
The satellites say the hottest recent year was 1998, and that since 2001 the global temperature has levelled off again blowing another hole in their broken theory but hey, lets cherry pick, homogenize and generally bend the data till it squeaks to keep the gravy train on its track.
Sorry Mike @ur momisugly 5:18 am but the last thing needed right now is a “What If” paper muddying the waters.
““This study shows that the climate is going to be drier on the way up and wetter on the way down,” Caldeira said, adding:”Proposals to cool the earth using geo-engineering tools to reflect sunlight back to space would not cause a similar pulse of wetness.””
I liked this one; it’s rather poetic – “drier on the way up and wetter on the way down” – like “what goes up must come down”… and “Pulse Of Wetness”.
The Pulse Of Wetness
Coming To A Nobel Prize Ceremony Near You Real Soon Now.
Oh what a pulse of wetness. Pulse me wet.
Mike says:
March 26, 2011 at 5:18 am
“It seems confusing at first. You may have to read it several times to get it.”
The moment it stops appearing confusing to you, you know the confusion has seeped into your brain, and confusing things now appear normal to you. From that moment on, your brain will stop processing normal input and become dependent on more confusing input. Until you find yourself craving more warmist modeling papers.
Problem:
if your model finds that CO2 affects jack, you’ve got no paper.
if your model finds that CO2 affects ANYTHING, you’ve got a paper. CO2 will make it hotter/colder, wetter/drier, windier/less windy, cloudy/less cloudy. Now you have a shiny paper. Congratulations. All you had to do was press “GO!” on your computer.
If these guys were modelling aerodynamics they would come up with:
CO2 causes more drag except when we would rather go slow, when it gives a dangerous and unexpected velocity boost eg at take-off or landing.
CO2 decreases lift except at high altitudes when our models show we could be sucked into the vacuum of space.
etc.
I think they have it backwards. Changes in sea surface temperature control the rates of evaporation/condensation in and out of the atmosphere as well as vertical convection. SST changes also control the rates of CO2 transfer between oceans and atmosphere. Cold water in clouds absorb CO2 and returns it to the oceans in rain thus tending to control the concentration of CO2 in air. So SST changes are controlling CO2 levels, not CO2 changes controlling SST. CO2 concentration changes will lag SST changes. They need to introduce different “what ifs?” into their models.