Climate change has less impact on drought than previously expected

August 29, 2016, University of California, Irvine
A photograph of a farmer showing his affected plot due to drought in Karnataka, India, 2012. Credit: Pushkarv/Wikipedia

As a multiyear drought grinds on in the Southwestern United States, many wonder about the impact of global climate change on more frequent and longer dry spells. As humans emit more carbon dioxide into the atmosphere, how will water supply for people, farms, and forests be affected?

A new study from the University of California, Irvine and the University of Washington shows that water conserved by under high CO2 conditions compensates for much of the effect of warmer temperatures, retaining more water on land than predicted in commonly used assessments.

According to the study published this week in the Proceedings of the National Academy of Sciences, the implications of plants needing less water with more CO2 in the environment changes assumptions of impacts on agriculture, water resources, wildfire risk, and plant growth.

The study compares current drought indices with ones that take into account changes in plant water use. Reduced precipitation will increase droughts across southern North America, southern Europe and northeastern South America. But the results show that in Central Africa and temperate Asia—including China, the Middle East, East Asia and most of Russia—water conservation by plants will largely counteract the parching due to climate change.

"This study confirms that drought will intensify in many regions in the future," said coauthor James Randerson, UCI professor of Earth system science. "It also shows that plant water needs will have an important influence on water availability, and this part of the equation has been neglected in many drought and hydrology studies."

Recent studies have estimated that more than 70 percent of our planet will experience more drought as carbon dioxide levels quadruple from pre-industrial levels over about the next 100 years. But when researchers account for changes in plants' water needs, this falls to 37 percent, with bigger differences concentrated in certain regions.

The reason is that when Earth's atmosphere holds more carbon dioxide, plants actually benefit from having more of the molecules they need to build their carbon-rich bodies. Plants take in carbon dioxide through tiny openings called stomata that cover their leaves. But as they draw in carbon dioxide, moisture escapes. When is more plentiful, the stomata don't need to be open for as long, and so the plants lose less water. The plants thus draw less water from the soil through their roots.

Global climate models already account for these changes in plant growth. But many estimates of future drought use today's standard indices, like the Palmer Drought Severity Index, which only consider atmospheric variables such as future temperature, humidity and precipitation.

"New satellite observations and improvements in our understanding hydrological cycle have led to significant advances in our ability to model changes in soil moisture," said Randerson. "Unfortunately, using proxy estimates of can give us misleading results because they ignore well-established principles from plant physiology."

Planners will need accurate long-term drought predictions to design future supplies, anticipate ecosystem stresses, project wildfire risks and decide where to locate agricultural fields.

"In some sense there's an easy solution to this problem, which is we just have to create new metrics that take into account what the plants are doing," said lead author Abigail Swann, a University of Washington assistant professor of atmospheric sciences. "We already have the information to do that; we just have to be more careful about ensuring that we're considering the role of the plants."

Is this good news for climate change? Although the drying may be less extreme than in some current estimates, droughts will certainly increase, researchers said, and other aspects of climate change could have severe effects on vegetation.

"There's a lot we don't know, especially about hot droughts," Swann said. The same drought at a higher temperature might have more severe impacts, she noted, or might make plants more stressed and susceptible to pests.

"Even if droughts are not extremely more prevalent or frequent, they may be more deadly when they do happen," she said.

Explore further: US absorbed carbon dioxide despite drought

More information: Plant responses to increasing CO2 reduce estimates of climate impacts on drought severity, Proceedings of the National Academy of Sciences, www.pnas.org/cgi/doi/10.1073/pnas.1604581113

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Shootist
2.1 / 5 (11) Aug 29, 2016
Climate change has less impact on drought than previously expected


Climate change: This most magnificent of frauds is omnipotent.
leetennant
4.3 / 5 (12) Aug 29, 2016
Having retreated as far as possible in the face of overwhelming scientific evidence, deniers are now claiming the "conspiracy" is sentient, self-aware and all-powerful. I guess that explains why the Arctic is in on it.
aksdad
2.2 / 5 (10) Aug 29, 2016
Demonstrating once again that the science is NOT settled about climate change. Lots of interesting stuff still being discovered that has a major impact on future projections.

Recent studies have estimated that more than 70 percent of our planet will experience more drought as carbon dioxide levels quadruple from pre-industrial levels over about the next 100 years.

What studies? The IPCC AR5 report in 2013 said this about drought:

Confidence is low for a global-scale observed trend in drought or dryness (lack of rainfall) since the middle of the 20th century...

If there are no observations of increased global (or 70% global) drought even as CO2 has increased and temperatures have increased (slightly) then why is anyone projecting future drought when observations currently show NO CORRELATION to CO2 or global temperatures? Because the (demonstrably inaccurate) computer models said so?

I guess that's what passes for science in climate studies now.
aksdad
2.8 / 5 (9) Aug 29, 2016
Sorry couldn't let this one go unchallenged, either:

...as carbon dioxide levels quadruple from pre-industrial levels over about the next 100 years.

Pre-industrial levels of CO2 are estimated to be about 0.028% of the atmosphere (280 ppm). Quadrupling that is 0.112% (1120 ppm). Extrapolating from the highest increases of CO2 over the last 5 years (average about 2.3 ppm), it will take until the year 2328 to reach that amount. That's 312 years from now, not 100 years.

In the next 100 years, IF human population continues to grow at current rates (which it won't, it will likely peak around 2050 and level off or decline) and IF human CO2 emissions continue to grow unabated (which won't happen because technological improvements and improvements in efficient energy use will reduce emissions) then we can expect to see about 0.063% CO2 (630 ppm). That's about 2.25 times pre-industrial levels, not 4 times pre-industrial levels.

http://www.esrl.n.../trends/
guptm
2.1 / 5 (11) Aug 29, 2016
Great exposition of the biggest propaganda and drama in the human history. Where there is money and power, false is portrayed as truth and is sustained and protected.

Future generations will adapt to their climate, no need to worry about them; like we adapted to our climate. A person from Younger Dryas would have certainly died in today's climate.

Adaptation - that is the beauty of the Earth and its all species.
leetennant
4.3 / 5 (11) Aug 29, 2016
Sure, we can totally adapt to Miocene conditions in one generation. Totes.
After all we're super special evolutionary snowflakes. With, like, money.
Eikka
2.7 / 5 (3) Aug 30, 2016
Sure, we can totally adapt to Miocene conditions in one generation.


But nothing so dramatic can happen over one generation. Mind, one human generation is about 20-30 years. A generation is defined as the time taken to reproduce. Culturally, a generation is people born roughly within a decade or so.

Consider the social and cultural changes from 1916 to 2016. Much of the world went from feudalism and subsistence farming to modern post-industrial economies with internet and obesity problems due to over-abundance.

There are still people alive today who were born into cultures that did not know electricity or penicillin. Nearly all of the modern world was made in just 4-5 generations of people.

Sigh
5 / 5 (4) Aug 30, 2016
Extrapolating from the highest increases of CO2 over the last 5 years (average about 2.3 ppm), it will take until the year 2328 to reach that amount. That's 312 years from now, not 100 years.
That's a linear extrapolation. The economic growth that governments attempt to achieve is exponential.

IF human CO2 emissions continue to grow unabated (which won't happen because technological improvements and improvements in efficient energy use will reduce emissions)
Will reduce carbon intensity, but unless technology improves on a faster exponential than economic growth, emissions will increase. And the last time I read about that, carbon intensity did not decrease fast enough to reduce emissions (if I remember correctly, that was in Prosperity without Growth, ISBN 978-1849713238).
antigoracle
1.7 / 5 (6) Aug 30, 2016
Sure, we can totally adapt to Miocene conditions in one generation. Totes.
After all we're super special evolutionary snowflakes. With, like, money.

It's impressive how you have adapted to life without a brain.
michael_frishberg
4.3 / 5 (3) Aug 30, 2016
Sure, we can totally adapt to Miocene conditions in one generation. Totes.
After all we're super special evolutionary snowflakes. With, like, money.

Exactly what the .0001 percenters are thinking. That's why they own just about EVERYTHING, so they can survive what they damn well know is coming, they paid for the research.

Too bad, quite sad, they won't succeed.

No mammal larger than a shrew (if them) will be alive on Planet Earth by 2120.

vhemt.org
leetennant
5 / 5 (2) Aug 30, 2016
Yep and the idea that they can buy their way out of this kind of climatic change is laughable. We are fucked and so are they.
howhot3
2.4 / 5 (7) Aug 30, 2016
Global warming is doing just that, warming the globe. And since 2/3's of the planet is covered in oceans, the biggest impact will be seen in the 2/3's covered by water. So class; what happens when you heat water? Correct! It evaporates as steam. Now what happens when the water cools? It turns back to water (Rain). Conclusion; If there really is global warming, then it should rain a lot. Look at the recent Louisiana flooding as on example of what to expect for the next 2000 years as the atmosphere continues to heat up from global warming.
antigoracle
2.1 / 5 (7) Aug 30, 2016
Look at the recent Louisiana flooding as on example of what to expect for the next 2000 years...

Oh, look what his man crush, Al, pooped out and surprise, it is seeing floods. Please enlighten us how man made global warming caused the worst flood in US history.
https://en.wikipe..._of_1927
jeffensley
2.3 / 5 (3) Aug 31, 2016
It's as if plants had already evolved to deal with previously similar environmental changes. How odd is that?
gkam
1.5 / 5 (13) Aug 31, 2016
jeffensley
1.7 / 5 (6) Aug 31, 2016
Better yet, how did the flood of 1771 occur in Richmond so early in the Industrial Revolution, before it's effects could even be felt? Nature just doesn't seem to care about narrative sometimes...

http://www.glenal...lpic.jpg
gkam
1.7 / 5 (11) Aug 31, 2016
The Aten works in mysterious ways.
Bongstar420
2.3 / 5 (6) Sep 01, 2016
Megadroughts occurred in the past without Homo sapian influence...I do believe many much higher magnitude events of multiple kinds did as well.

The Earth's climate is naturally quite variable with many events resulting in +5C changes within the time span of century or two.
leetennant
4 / 5 (8) Sep 01, 2016
I'm sorry, did you just say that the Earth's average global temperature fluctuates by 5 degrees a century?

Just out of curiosity - what parallel universe are you in? Is it pretty? And are the unicorns friendly?
jeffensley
3 / 5 (6) Sep 02, 2016
I'm sorry, did you just say that the Earth's average global temperature fluctuates by 5 degrees a century?

Just out of curiosity - what parallel universe are you in? Is it pretty? And are the unicorns friendly?


I really don't know why your post would be rated positively. I would think folks so opinionated about AGW would know something about past climate change. During the end of the Younger Dryas period for example "very rapid warming at the start of the Bölling-Alleröd period, or at the end of the Younger Dryas may have occurred at rates as large as 10°C/50 years for a significant part of the Northern Hemisphere."

https://www.ipcc..../074.htm
geokstr
2 / 5 (10) Sep 02, 2016
I really don't know why your post would be rated positively.


It's tribal.

Pro-AGWs give automatic 5 stars to those they know that agree with them, even if they have no clue what a given comment means, and automatic one star to those they derisively call "deniers", no matter how reasonable their comment. Now, this also happens with the AGW skeptics as well, but with a major exception - for the pro-AGWs, no heresy, even minor, is permitted, because it's their religion. They make fun of religions with gods, while the only major difference is that their own doesn't have one.

gkam
1.8 / 5 (10) Sep 02, 2016
Deniers with "reasonable comments"?

My reverence is for life, not some imaginary and scary rumor from the Age of Ignorance.
howhot3
5 / 5 (5) Sep 02, 2016
Typical of the BS that the Trump crush loves to spread. Mankind may not have put the droughts where they are, and current climate patterns may not be effecting the drought conditions as much, but that doesn't matter for anything. What does matter is the FACT that global average temperatures increase will be hitting 4+ C degrees in less than 100 years! My good butt buddy friend @antigoracle would have you believe this is all some Al-Gore joke.
No it isn't and you deniers are pieces of crap that deserve all the ridicule you receive.

With respect to the flood that occurred in Louisiana a week or so back, @Gkam spotted it perfectly... it's this; https://assets.rb...980x.jpg

And it only gets more depressing as you extend the computer model projections from years into decades.
philstacy9
1 / 5 (6) Sep 02, 2016
Climate change has less impact than previously expected.
leetennant
5 / 5 (4) Sep 03, 2016
I'm sorry, did you just say that the Earth's average global temperature fluctuates by 5 degrees a century?

Just out of curiosity - what parallel universe are you in? Is it pretty? And are the unicorns friendly?


I really don't know why your post would be rated positively. I would think folks so opinionated about AGW would know something about past climate change... "very rapid warming at the start of the Bölling-Alleröd period, or at the end of the Younger Dryas may have occurred at rates as large as 10°C/50 years for a significant part of the Northern Hemisphere."


It's tribal.


Yep, it's tribal. Nothing to do with Bongstar's comment being flipping ridiculous or that your "counter argument" was to cite rapid regional (not global) change 12000 yrs ago. So unless you have some amazing data that shows that temps vary globally "by up to 5 degrees a century", then accept the truth.

You get down-voted because the comments you make are dumb
ikihi
1 / 5 (2) Sep 04, 2016
U.S. Data Since 1895 Fail To Show Warming Trend http://nyti.ms/1nS5YgG
SteveS
5 / 5 (1) Sep 04, 2016
U.S. Data Since 1895 Fail To Show Warming Trend http://nyti.ms/1nS5YgG


A 25 year old New York Times article about US temperatures, 1.5 percent of Earths surface, that quotes the meteorologist who led the study as saying: -

"the findings concerning the United States do not necessarily ''cast doubt'' on previous findings of a worldwide trend toward warmer temperatures, nor do they have a bearing one way or another on the theory that a buildup of pollutants is acting like a greenhouse and causing global warming."

This is the second time you've posted this, what point are you trying to make?
Thorium Boy
1 / 5 (1) Sep 04, 2016
Every time a climate change effect is proven mitigated, or lessened and every positive there is about a warmer climate ENRAGES the enviros and the greenies who see their grand socialist plot threatened.
jeffensley
1 / 5 (1) Sep 06, 2016
Yep, it's tribal. Nothing to do with Bongstar's comment being flipping ridiculous or that your "counter argument" was to cite rapid regional (not global) change 12000 yrs ago. So unless you have some amazing data that shows that temps vary globally "by up to 5 degrees a century", then accept the truth.

You get down-voted because the comments you make are dumb


Sorry but I've read FAR more "dumb" and un-cited arguments coming from the AGW

Admit that you don't like the fact that dramatic climate changes happen with or without our influence and that such knowledge reduces the dire and "unprecedented" nature of your narrative of fear regarding AGW.
gkam
1 / 5 (7) Sep 06, 2016
AGW is real.

The nonsense we tell ourselves in religion is not.
jeffensley
1 / 5 (2) Sep 06, 2016
Every time a climate change effect is proven mitigated, or lessened and every positive there is about a warmer climate ENRAGES the enviros and the greenies who see their grand socialist plot threatened.


I agree with everything but the "grand socialist plot" part. These folks claim to be on the side of science yet they can't bear to accept any study that casts doubt on methodology, suggests there will be benefits to a warmer planet, or concludes that AGW may not happen as quickly or have as dire effects as predicted. Their narrative often appears to be about driving the creation of fear-based legislation and taking fear-based action.
gkam
1 / 5 (8) Sep 06, 2016
jeff, I earned a Master of Science in this field, . . not a MA, but a MS.

It was rigorous, and we do not need some ignorant folk seduced by superstition to tell us we are wrong because folk who "believe" like those in the Age of Ignorance says so.

You have convinced yourself that we are flawed like you.

We are not.
jeffensley
not rated yet Sep 06, 2016
jeff, I earned a Master of Science in this field, . . not a MA, but a MS.

It was rigorous, and we do not need some ignorant folk seduced by superstition to tell us we are wrong because folk who "believe" like those in the Age of Ignorance says so.

You have convinced yourself that we are flawed like you.

We are not.


No, unfortunately if that's how you actually feel, I'd rank you as a bit MORE flawed than the average person. Your arrogance blinds you to the failings/weaknesses inherent in research and even more so in prediction. You put defense of a particular narrative ahead of healthy skepticism and rational humility. That has nothing to do with the scientific method and everything to do with treating Science as an infallible god to be worshiped and never questioned.
gkam
1 / 5 (7) Sep 06, 2016
No, jeff, you are projecting, and hoping I am like you.

I am not. I have been watching this since my degree in 1982, and sometimes resent those with less education than axe to grind hurling assertions and accusations at us.
Uncle Ira
4.4 / 5 (7) Sep 06, 2016
and sometimes resent those with less education
And the ones with more education a lot more,,,,,, all the times.
TheGhostofOtto1923
4.2 / 5 (5) Sep 07, 2016
I am not. I have been watching this since my degree in 1982, and sometimes resent those with less education than axe to grind hurling assertions and accusations at us
You lied about what that honorary MS you bought was for. You lie about most everything every day.

And you think the people who object to this behavior and who take the time to warn others because it is the right thing to do, envy you for some strange reason.

George kamburoff lies because he is a very sick person, and everybody who has been here for any length knows this full well. Why on earth would you think this is something that people would envy?
gkam
1 / 5 (6) Sep 07, 2016
Poor otto. I turned out to be real after otto screamed "LIAR!" and filthy words at me. No, he did not get embarrassed, he doubled down.

Notice how he hides his real name? He also cowers behind a phony cutout, too SCARED to take responsibility for his nasty words.

A coward.

The internet is full of anonymous cowards. But we are going to stop the otto.

http://www.bbc.co...35712772
Uncle Ira
4.3 / 5 (6) Sep 07, 2016
@ glam-Skippy. How you are Cher? Oh yeah, I'm good, thanks for asking.

But we are going to stop the otto.

http://www.bbc.co...35712772


And you wonder why you are getting so much ridicule and derision here? Ol Otto-Skippy has been drawing that warning for 10 years now,,,,, how long before we see a little action? When you was the kid in school,,,,,, were you the kid who kept on telling everybody that your daddy was going to beat them up whenever you bite off more than you could chew up? Tell the truth, you got slapped around a lot when you was little, eh? Probably still get slapped around a lot, eh?

Anyhoo, you used up all the "see you court" wolf tickets months ago.
gkam
1 / 5 (6) Sep 07, 2016
Oh, it's "Ira", another anonymous sniper.

The lowest form of artificial life is the anonymous sniper. They have insufficient guts to use their real name and take responsibility for their own nasty words.

It is a display of poor character.
Uncle Ira
4.3 / 5 (6) Sep 07, 2016
Oh, it's "Ira", another anonymous sniper.


For a genius you sure are not very bright. Oh, of course it's me. It's got my name right up there for you to see. What, you thought someone was stealing my anonymous identity on the interweb?

They have insufficient guts to use their real name and take responsibility for their own nasty words.
Ira is my real name. And I can take all the responsibility you can hand out. Why you don't come on down here and give me a little of that responsibility,,, it will let me slap you all the way back to California with one slap?

So now you know my real name, what's next? You going to take me to the court like you aren't Otto-Skippy either? The High Sheriff he knows me good, he'll know right where to find me. So we can have the good laugh together at those goofy couyons from California.
gkam
1 / 5 (6) Sep 08, 2016
Yeah, . . . sure.

Why are you hiding?

From whom?

Why are you so scared to tell us who you really are?

I think it is because you are a phony.

Internet snipers are lower than any form of real life.
TheGhostofOtto1923
4.2 / 5 (5) Sep 08, 2016
Why does george kamburoff hide behind lies about his past, his education, his experience? Is it because his life is the obvious disaster that it appears to be? A dozen or so failed jobs, college dropout, bought-and-paid-for phony MS, VA mental patient, 40 year pothead, lying about his non-existent PV and EV, lying about his phony mil service and phony awards, etcetc.

You cant hide the fact that youre an complete and utter loser george. You cant hide the fact that youre so stupid youve exposed all your personal info online including your SS# because youre such a hopeless clumsy braggart.

Just think of all the anonymous people out there who read all this and laugh.

Just think of all the people you know who can do a simple google search and find all the shit youve posted here.

Arent you ashamed?

Of course not. Psychopaths dont feel shame or much of anything else for that matter.
TheGhostofOtto1923
4.2 / 5 (5) Sep 08, 2016
And please do not forget - knowing who your anonymous detractors are will not change any of what youve done here. And it will NOT stop people from exposing your lies and made-up facts and showing the world just who and what the REAL george kamburoff really is.

That is just something else you have absolutely no control over.
gkam
1 / 5 (6) Sep 08, 2016
Outgrow your need to get even with those who have beaten you, "otto". You admitted long ago how you use variations of "otto", such as Tooty as pseudonyms to play what you call your "games".

You also hide behind a cutout, too SCARED to take responsibility for your silly words.

Lowest form of phony life, "otto". Get a real one.
TheGhostofOtto1923
4 / 5 (4) Sep 08, 2016
Outgrow your need to get even with those who have beaten you, "otto". You admitted long ago how you use variations of "otto", such as Tooty as pseudonyms to play what you call your "games".

You also hide behind a cutout, too SCARED to take responsibility for your silly words.

Lowest form of phony life, "otto". Get a real one.
According to george kamburoff most everyone here is a member of the lowest form of life. This is one of the few places george can come and pretend hes better than everybody, and not get fired and not get thrown out and not get the crap beat out of him.
https://www.youtu...FfHHVmKw

-Yeah I know its fake. Just like george kamburoff and his fake medals.

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