Heat, Not Just Rainfall, Plays into New Projections
Increasing heat is expected to extend dry conditions to far more farmland and cities by the end of the century than changes in rainfall alone, says a new study. Much of the concern about future drought under global warming has focused on rainfall projections, but higher evaporation rates may also play an important role as warmer temperatures wring more moisture from the soil, even in some places where rainfall is forecasted to increase, say the researchers.
The study is one of the first to use the latest climate simulations to model the effects of both changing rainfall and evaporation rates on future drought. Published this month in the journal Climate Dynamics, the study estimates that 12 percent of land will be subject to drought by 2100 through rainfall changes alone; but the drying will spread to 30 percent of land if higher evaporation rates from the added energy and humidity in the atmosphere is considered.
An increase in evaporative drying means that even regions expected to get more rain, including important wheat, corn and rice belts in the western United States and southeastern China, will be at risk of drought. The study excludes Antarctica.
“We know from basic physics that warmer temperatures will help to dry things out,” said the study’s lead author, Benjamin Cook, a climate scientist with joint appointments at Columbia University’s Lamont-Doherty Earth Observatory and the NASA Goddard Institute for Space Studies. “Even if precipitation changes in the future are uncertain, there are good reasons to be concerned about water resources.”
In its latest climate report, the International Panel on Climate Change (IPCC) warns that soil moisture is expected to decline globally and that already dry regions will be at greater risk of agricultural drought. The IPCC also predicts a strong chance of soil moisture drying in the Mediterranean, southwestern United States and southern African regions, consistent with the Climate Dynamics study.
Using two drought metric formulations, the study authors analyze projections of both rainfall and evaporative demand from the collection of climate model simulations completed for the IPCC’s 2013 climate report. Both metrics agree that increased evaporative drying will probably tip marginally wet regions at mid-latitudes like the U.S. Great Plains and a swath of southeastern China into aridity. If precipitation were the only consideration, these great agricultural centers would not be considered at risk of drought. The researchers also say that dry zones in Central America, the Amazon and southern Africa will grow larger. In Europe, the summer aridity of Greece, Turkey, Italy and Spain is expected to extend farther north into continental Europe.
“For agriculture, the moisture balance in the soil is what really matters,” said study coauthor Jason Smerdon, a climate scientist at Lamont-Doherty. “If rain increases slightly but temperatures also increase, drought is a potential consequence.”
Today, while bad weather periodically lowers crop yields in some places, other regions are typically able to compensate to avert food shortages. In the warmer weather of the future, however, crops in multiple regions could wither simultaneously, the authors suggest. “Food-price shocks could become far more common,” said study coauthor Richard Seager, a climate scientist at Lamont-Doherty. Large cities, especially in arid regions, will need to carefully manage their water supplies, he added.
The study builds on an emerging body of research looking at how evaporative demand influences hydroclimate. “It confirms something we’ve suspected for a long time,” said Toby Ault, a climate scientist at Cornell University, who was not involved in the study. “Temperature alone can make drought more widespread. Studies like this give us a few new powerful tools to plan for and adapt to climate change.”
Rainfall changes do not tell the whole story, agrees University of New South Wales researcher Steven Sherwood, in a recent Perspectives piece in the leading journal Science. “Many regions will get more rain, but it appears that few will get enough to keep pace with the growing evaporative demand.”
The authors have made all their data and calculations public available on a supplementary website.
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the one to watch is agriculture for how the climate is effecting us.
http://www.thecropsite.com/reports/?id=2753
“Increasing heat is expected to extend dry conditions to far more farmland and cities by the end of the century than changes in rainfall alone, says a new study.”
The Malthusian expectations were sorely disappointed before. Both the revolution in crop varieties brought about by Norman Borlaug, and the mass production of tractors increased yield on farmland so that an acre of land can now produce 5 times what it once did; also, 2/3s and the land was no longer being used to feed the horses and oxen because of the mass manufacturing of gas driven tractors.
EC Stakman found over 300 varieties of rust which migrated between Mexico and Canada each year. With the control of rust, scab, smut, blight, and countless other pathogens, our land is prosperous.
The progressive scientists have never forgotten this spoiling of their “expectations.” If politicians listen to these progressive scientists, then water restrictions, legislation, and anti-agricultural activists will fulfill the water shortage prophecies for them.
April Fool!
Cosmic radiation increases. The current shape of the polar vortex on 100 hPa.
http://oi60.tinypic.com/noiwhv.jpg
Yet another computer model prophesies doom within a century. Short enough time to scare, long enough to avoid ever being tested.
Basic physics? What happens to a world covered 75% with water as it warms? More water in the atmosphere? I guess that makes the oceans dryer. I’m confused.
Climastrology physics and regular physics. Never the twain shall meet.
@ur momisugly ren, 1, 2, 3, 4, ,,,
The post is about land, heat, and rainfall in the future, that is– will drought in the years near 2100 be a serious problem to the peoples of Earth?
You have linked (with no reasons given with respect to the post) to at least 5 colorful images that have no explanatory information with them:
Sunspots (whose count?), Ap index, K index for mid-Sept-2005, Current Temp. above the North Polar region, and uSv/hr at 15km above the Northern Hemisphere.
The colors are nice but as far as I can tell none of these has anything to do with the topic and, further, what they do have to do with I cannot tell. This suggests to me that the name of the noble son is ren:
From Shakespeare’s Hamlet, 1602:
LORD POLONIUS
This business is well ended.
My liege, and madam, to expostulate
What majesty should be, what duty is,
Why day is day, night night, and time is time,
Were nothing but to waste night, day and time.
Therefore, since brevity is the soul of wit,
And tediousness the limbs and outward flourishes,
I will be brief: your noble son is mad:
Mad call I it; for, to define true madness,
What is’t but to be nothing else but mad?
But let that go.
Martin A says:
April 1, 2014 at 1:10 am
Nailed it. This “study” should be called computer assisted speculations about drought.
The safest forecast is a very long range forecast. Nobody of today will be alive to verify it.
Who has time to Debunk this Alarmist Counter??
http://4hiroshimas.com/
Anthony I think you need to make one also, there is so many things that can be put on one.
The ‘climate change’ they talk about is clearly based on ‘global warming’. A phrase they shyed away from when it was clear that global warming was not happening. With no warming for seventeen years; the Arctic and Antarctic ice melt not happening; the polar bears growing in numbers; the coral reefs not disappearing as forcast; one of the coldest winters of the the Northern Hemisphere on record, which was not forcast by the ‘team’; the seas not warming or rising as the ‘team ‘ forcast; Viner’s “our children will not see snow in a few years” forcast in 2000, proving to be wrong etc. etc. Can anyone please tell me on what climatic conditions the IPCC base their doomsday forcasts, and what right do they have to scare the world into spending £$ billions on mitigating a problem that clearly does not exist? Forcasts that lead to gullible students like Cook,Smeardon and Seager coming up with the laughable studies like this one, that are so readily torn to shreds when the historical record, empirical record, and simple physics are applied to their papers.
Joe R says:
April 1, 2014 at 7:27 am
So exactly how does CO2 “trap” heat?
****
CO2 can not trap heat.
What it can do is absorb energy and release said energy back into it’s environment.
What the environment does with said energy is another topic.
….. …
See Frank Wentz (RSS) et al.
One deg. C Temperature rise (global surface) produces a 7% increase in Total global evaporation, Total atmospheric water content, and Total global precipitation. This is experimental data, not terra-flop models.
I is not inconceivable, that total global (precipitable) cloud cover wouold also increase by something of the order of 7%; given that clouds are often observed to be present, during events of precipitation (of water) from the atmosphere.
There are no reports of clouds being present when it is raining cats and dogs, or frogs, and fish.
When rainfall increases, in intensity and longevity, the ground becomes more porous, and that water propagates to deeper layers, where it is immune to evaporation due to local surface temperatures. Surface drying is usually a consequence of inadequate watering; not of excessive watering.
And that phony picture of destroyed crops, is actually of a farm area where the crop has already been harvested. In California, that dried material would next be set on fire, to reduce the material to ashes, that can be carried back into the soil, as useful nutrients for the next crop.
Zeke wrote:
>>> The Malthusian expectations were sorely disappointed before. Both the revolution in crop varieties brought about by Norman Borlaug, and the mass production of tractors increased yield on farmland so that an acre of land can now produce 5 times what it once did; also, 2/3s and the land was no longer being used to feed the horses and oxen because of the mass manufacturing of gas driven tractors.<<<
In what kind of a crazy world is Paul Ehrlich and his ilk so worshipped and adored by the scientific community – and Norman Borlaug's achievements are largely ignored?
…why? because Borlaug was a scientist who actually cared about the human race. Many of these CAGW scientists, in my personal opinion, are rooting for increased human suffering – to advance their careers – instead of trying to reduce human suffering, like Borlaug did. Misanthropes.
_Jim says:
Jim, we might be reduced to smoke signals.
Totay’s Department of Water Resources California Water News carries an article about a joint media presentation by Pacific Institute and NRDC:
http://mavensnotebook.com/2014/03/31/this-just-in-pacific-institute-the-nrdc-hold-media-call-on-californias-drought-hydrology-not-environmental-restrictions-are-the-reason-for-the-low-allocations-plus-how-the-state-can-prepar/
This just in … Pacific Institute & the NRDC hold media call on California’s drought: Hydrology, not environmental restrictions, are the reason for the low allocations, plus how the state can prepare for droughts in the future
Maven, Maven’s Notebook
Earlier today, the Pacific Institute and the NRDC held a media call in anticipation of the final snow survey tomorrow. During the call, Peter Gleick, director of the Pacific Institute, discussed the science and hydrology of the drought, Doug Obegi, staff attorney with the NRDC discussed the allocations and how water is used in California, and Steve Fleischli with the NRDC discussed actions the state and its residents could be taking to address the currnet drought and prepare for future ones.
The only thing at its tipping point is my patience for the volumes of stupidity that are being published in climate journals.
Seems to me, that even if they are right (which I doubt) the solution would be to build more dams to catch the extra rainfall. Its a win-win, more hydroelectricity and more water for irrigation and people. Why does EVERYTHING always have to be DOOM AND GLOOM with these guys? Always the pessimist they are.
The study is one of the first to use the latest climate simulations to model the effects of ……..
Stopped reading after reading that. 😱
Frodo says, “Borlaug was a scientist who actually cared about the human race. Many of these CAGW scientists, in my personal opinion, are rooting for increased human suffering – to advance their careers – instead of trying to reduce human suffering, like Borlaug did. Misanthropes.”
Borlaug was a true scientist. The goal of science is to bring new powers and appreciation to human life, according to Bacon. It is not to count molecules, analyze “risk,” and reverse advancements. What these environmental activists are practicing is not science.
Borlaug also cared about the natural wild. By utilizing the land most effectively, the wild areas are not needed for foraging and hunting. High yield grains, beef and dairy cattle, and chickens provide all that is needed to raise healthy kids, without having to take up twice to five times as much land, or catch small wild animals. That is why Norman Borlaug worked so hard to bring his crops to Asia, Mexico and Africa. He was shocked at the environmentalists who opposed him, and who attacked his funding, in order to keep these agricultural advancements (new strains, chemical fertilizers, and pest control) out of Africa.
As Adam Smith said, it is the scourge of “well-intentioned” governments that turn nature’s temporary droughts into a prolonged famine and dearth.
Jim Happ says:
April 1, 2014 at 6:55 am
“What goes up must come down.”
No, Jim. What goes up stays up. Newton’s Fourth Law of Evaporation.
New paper finds mid-Holocene, which was warmer than the present, led to a wetter, “green” Sahara Desert
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00690.1
What really dries things out fast is direct sunlight. When it rains during growing season, you see plants go through a growth spurt. Not to mention CO2 increases growth. So don’t bigger plants shade more soil?
Also, when the soil dries we get cracks everywhere. If there is more rain after a dry spell, a bunch of it gets absorbed deep before it has any chance of evaporating. In marginal areas prone to long times between rain, that extra absorption should be good for replenishing the ground water, which in turn allows more irrigation, more plants, more shaded soil.
I think it would be hard to program such things into a model.