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.
I heard that global warming might have made the earthquake and tsunami in Japan, worse.
I guess the logic there is that global warming (especially AGW) dehydrates the ocean waters, which makes the tsunami lighter (therefore higher and faster) and also far more able to absorb water (therefore increasing in mass).
The fact is, tsunami destructive force was increased exponentially by AGW[!]
I continue to weep for science – is there anyone currently working in climate science who can speak out and say, “We cannot model what we do not comprehend!”?
It is only a model of course.
If you actually bothered to compare observations over many years you would find a very different answer.
But far be it for me to question this wonderful balderdash.
Kindest Regards
It’s quite simple, really: Global warming has the intrinsic ability to cause humidity to simultaneously increase and decrease in the same place.
On a more serious note, I’l love to see someone who supports both this and the old rubric that global warming causes more severe storms (which are claimed to be more severe due to increased convection!) try to explain themselves.
“… The results of this study show that cutting the concentration of precipitation-suppressing carbon dioxide in the atmosphere would increase global precipitation…”
So, increased CO2 causes less precipitation? I wonder how the plant life of the Carboniferous period got by on so little water. At about 800 ppm CO2, it must have been as dry as a bone…
Is this a Tim Flannery correction already? Where is the /sarc tag?
Whoa there
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.
Isn’t this where reality differs from “models” – the middle atmosphere is not warming as fast as their models predicted – or have I missed something somewhere
Andy
Modeling and it all MAY
Perhaps we need to excise the month of May to reduce the effect. or, add another month of May to increase the effect. It may/could perhaps happen one way or the other, fifty fifty chance, possibly….thats the way I read it.
This shows that global precipitation is increasing with increasing with increasing CO2 http://www.bom.gov.au/cgi-bin/climate/change/global/timeseries.cgi?graph=global_r®ion=global&season=0112&ave_yr=0,
then they say that …
“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.”
And Australia’s recent ten year drought was caused by CO2 increase they(AGW scientists) said , and it would get worse and worse they(AGW scientists) said …now we have floods and floods and more floods, which is also now caused by CO2 increase they(AGW scientists) say…and decreasing CO2 will cause more precipitation they (AGW scientist) say……..Excuse me, my mind has become befuddled with confusing contradictions and opposite statements!……what does it cause and what does not it cause?!…….Me thinks they(AGW scientists) have lost the plot!!!
“I guess the logic there is that global warming (especially AGW) dehydrates the ocean waters, which makes the tsunami lighter (therefore higher and faster) and also far more able to absorb water (therefore increasing in mass).
The fact is, tsunami destructive force was increased exponentially by AGW[!]”
Yes, that is probably the logic behind the claim. In a nutshell “since it is lighter, it becomes more heavy”. Clearly on the same line as “since it is warmer it becomes cooler”.
According to recent research, Western Australia is greening up, in part due to the breaking of a decade-long drought. During this period , we are told, the amount of plant food in the atmosphere has been increasing. Using the logic of the authors of this paper, surely then it would follow that increased CO2 in the atmosphere leads to increased precipitation in arid areas?
So let me see if I’ve got this right:
NE Aus is very wet at the moment so more CO2 will make it drier.
But it used to be quite dry there and the extra CO2 made it wetter.
Now I get it; CO2 makes everything happen.
Seems to me this post is just a few days early.
It think the increasing amount of CO2 in the atmosphere is causing climate scientists to become befuddled in their thinking, a bit like Apollo 13.
“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.”
How on earth can a trace gas have this affect? What scientific evidence as compared against a null hypothesis and not a computer model as stated can they make such a statement. A computer model can only give the answer that it is programmed to give.
Yet another model…
Can we just stop funding this crap research?
“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.”
This whole article is rubbish! CO2 does not and cannot “trap” heat anywhere in the atmosphere, it just scatters IR in all directions. That is not trapping, that is scattering. And IR is NOT heat, it is electromagnetic radiation, NOT heat. If a CO2 molecule were to convert the IR from the narrow waveband with which CO2 can interact into heat energy (i.e vibration), the gas would heat up and when a gas heats, it rises, the CO2 would then release the heat as IR radiation higher up in the atmosphere until it escapes into space. This is not “trapping” heat at all.
Plus, the so-called greenhouse gas “hot spot” has never been found, it does not exist because the whole CO2 theory and the modelling derived from this idea is utterly false. see here http://www.tech-know.eu/uploads/A_lesson_on_basic_physics.pdf
If it looks like a climate scientist
Talks like a climate scientist
Then its a Quack?
ROFLMAO…
and when there were lower levels of CO2, there were never droughts ?
These guys should look at some history !!
Ermmmm… if what they say happened to be true… I mean, a higher temperature up in the atmosphere preventing the rising air that causes thunderstorms by carrying humidity… wouldn’t that destroy the water vapour positive feedback that is claimed by IPCC to support their disproportionately big climate sensitivity estimations? And if it destroyed the water vapour positivew feedback, wouldn’t the temperature increase up in the atmosphere be smaller than modelled? And then, wouldn’t the whole idea be stupid enough not to think about it ever again?
You have to give them credit. Older AGW scare stories only predicted one thing: such as a warmer climate or the disappearance if winter snow. But now they are getting smarter and predicting opposite ends of the spectrum all at once in the same paper! But sadly there’s more that they missed. Drier places can get drier and wetter placed can get wetter… In addition wetter places can get drier and drier places can get even wetter.
‘Trapped heat in the mid troposphere’?
Firstly you can not trap heat or store it because whatever you do it will always flow away. You can reduce the flow by insulation but you can’t stop the flow to trap it or store it.
Secondly this mythical heat in the mid troposphere has yet to be found. The models state that it is there because of the Greenhouse Effect but try as we might we can’t find it. The atmosphere insists on cooling adiabatically as observations show.
Once again we have a claim built upon some model based research which will not/cannot follow the real world. Total rubbish.
What goes up must come down. If it is warmer then there is more evaporation so more water goes up and then more water comes down. What am I not understanding? Or will a giant, ever growing lake form in the sky or maybe more clouds? I’ll be able to save on sunscreen.
And on the question of “Carbon dioxide traps heat in the middle of the atmosphere” has this hot spot predicted by models now been found? I remember debating with someone who said ‘you can’t trust the balloons and satellites to measure temperature in the troposphere, you have to work it out from wind speed/shear up there’.
Or maybe it’s a different middle of the atmosphere.
I’m seeing the light http://en.wikipedia.org/wiki/'Pataphysics
Alfred Jarry, the founder of ‘Pataphysics would be proud of Global Warming science.
In a crazy way, they are right but not how they know it. Look at the weather during the LIA (Little Ice Age). There were droughts (some very bad ones) and there was a lot of rain—it being cold and wet across Europe far more than the Europeans were used to (which is why the witch hunts began and Renaissance paintings show such horribly cloudy skies … when they show the outdoors at all).
And, during the Little Ice Age, the atmospheric CO2 level was lower than it is now: about 280 ppm.
Therefore, reduce the CO2 level and you increase the rain.
Q. E. D.
There were droughts during this period too, but we’ll hide the decline (of the rainfall) as it’s a permissible “trick.”
The predicted hot spot isn’t there, as confirmed by thousands of balloon carried thermometers and millions of satellite readings.
By relying on the predicted hot spot, rather than the measured lack of a hot spot, this is another “postmodern” science, where a researcher examines the models and ignores the reality. It’s the exact opposite of science.
They don’t even bother to discuss the non-existence of the hot spot.
So: “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. ”
What if the contrary is?
That is: if Henry’s law works to rain droplets too, it’s more logical to me imagine a CO2 atmospheric depletion due to the wetter climate than vice versa.
But, I’m not a scientist and I’m surely wrong 🙂