Increased flooding driven by climate change: study

Feb 16, 2011 by Marlowe Hood
A woman wades across a flooded area of Jardim Itaim neighbourhood, eastern outskirts of Sao Paulo, Brazil, on January 2011. Global warming driven by human activity boosted the intensity of rain, snow and consequent flooding in the northern hemisphere over the last half of the 20th century, research released Wednesday has shown.

Global warming driven by human activity boosted the intensity of rain, snow and consequent flooding in the northern hemisphere over the last half of the 20th century, research released Wednesday has shown.

Two studies, both published in Nature, are among the first to draw a straight line between and its impact on potentially deadly and damaging .

Australia, Sri Lanka, Brazil and Pakistan have all been recently ravaged by massive flooding, raising questions as to whether global warming was at least partly to blame.

Computer models have long predicted that the observed rise in atmospheric greenhouse gases would magnify episodes of diluvian rainfall.

But up to now, the link has been largely theoretical.

"This paper provides the first specific evidence that this is indeed the case," said Francis Zwiers, a researcher at the University of Victoria in Canada and a co-author of one of the studies.

"Humans influence the intensity of precipitation extremes," he told journalists in a telephone press conference.

Data gathered between 1951 and 2000 from across Europe, Asia and North America showed that, on average, the most extreme 24-hour precipitation event in a given year -- whether , snow or sleet -- increased in intensity over the last 50 years of the 20th century.

When this measurable spike was compared with changes simulated by , the fingerprint of human influence on Earth's was unmistakable, Zwiers said.

An aerial photo taken on February 3, shows the aftermath of Cyclone Yasi at Tully on February 3. Global warming driven by human activity boosted the intensity of rain, snow and consequent flooding in the northern hemisphere over the last half of the 20th century, research released Wednesday has shown.

"The observed change cannot be explained by natural, internal fluctuations of the climate system alone."

The main driver was simply more water in the air. "In a warmer world the atmosphere has greater moisture-holding capacity," he explained.

That doesn't necessarily mean that in a place where it doesn't rain very much precipitation will increase, he added. Indeed, some spots on Earth are likely to be drier.

But it does mean that when a hurricane or does occur, there is more water available.

Why did it take so long for scientists to begin to make solid connections between global warming and extreme weather events?

One reason is that only in recent decades has the accumulated influx of heat-trapping gases become more obvious. "We are finding it easier and easier to detect that signal in observations," Zwiers said.

Progress has also been hampered by the lack of reliable, long-term data, and the sheer computer power needed to test ever-more complex computer models against reality.

In the second study -- which sought to tease out the impact of global warming on England's wettest autumn on record, in 2000 -- scientists led by Myles Allen of the University of Oxford tapped into the power of Internet-based social networks to overcome this last constraint.

The researchers compared two climate models, one based on detailed historical weather data and the other on a "parallel" autumn 2000 simulating conditions had no greenhouse gases been emitted in the 20th century.

A large catamaran lies upsidedown on the porch of a luxury waterfront home in Cardwell on February 4. Two studies, both published in Nature, are among the first to draw a straight line between climate change and its impact on potentially deadly and damaging extreme weather events.

likely doubled the odds that such an event would occur, they found.

"To really pin down the difference between these two worlds, we needed to repeat the simulation thousands of times," explained lead author Pardeep Pall, who initiated the project as a graduate student in 2003.

"We asked members of the public across the world to run the simulations for us on their own personal computers using their idle time."

Based on the results of the study, Britain national climate and weather office is developing tools to measure the human influence on future extreme weather events.

"This kind of study is going to allow us to quantify how climate change is affecting people now so it ceases to be some hypothetical projection of the future," said Allen.

The tool could also be useful in legitimating requests from developing countries seeking to tap into the hundreds of billions of dollars earmarked for climate adaptation, he said.

Members of the public interested in lending computing power can find information at climateprediction.net, which is currently fueled by 50,000 to 60,000 personal computers at any given time.

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User comments : 30

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gmurphy
3.1 / 5 (23) Feb 16, 2011
Now of the same old tired parade of deniers, 3, 2, 1...
Skepticus
2.5 / 5 (19) Feb 16, 2011
No doubt the AGW drool will make up for the majority of the volume of the floods.
GSwift7
2.1 / 5 (22) Feb 16, 2011
Now of the same old tired parade of deniers, 3, 2, 1...


Care to tally up the score on how many alarmist predictions throughout history have been right and how many have been wrong?

Wanna place bets on whether human influence, and especially CO2, is the biggest influence of climate change? I would bet that land use and aerosols play some role, but science is currently unable to quantify that role relative to CO2. That's a pretty big question mark.

How's that for the usual denialist parade? Is that good enough? I know, having to actually look at facts and talk about how you might be wrong is hard, but that's how science is supposed to work. It's called skepticism, by the way. Why don't you drop that tired old comparison to nazi holocaust denial, please?
sams
4.4 / 5 (14) Feb 16, 2011
"Care to tally up the score on how many alarmist predictions throughout history have been right and how many have been wrong?"

It would be silly to tally 'alarmist predictions'. Much better to tally the record of how many strongly held predictions made by the scientific institutions of the developed world in the last few decades have come true.
gmurphy
3.6 / 5 (20) Feb 16, 2011
Alarmist predictions come and go. Global warming research has steadily built up a strong case based on decades of research whilst simultaneously fending off misinformation campaigns run by oil companies and other vested interests. Whilst there have been exaggerations, mistakes and alarmist statements, the vast body of the research has consistently pointed to more frequent extreme weather events, backed up by consistent observations, such as those described in that article. Anyone willing to outright deny such evidence throws their lot in with the creationists and the other nuts, IMHO.
Sean_W
1.9 / 5 (17) Feb 16, 2011
WOLF!!!!!!!!

"Australia, Sri Lanka, Brazil and Pakistan have all been recently ravaged by massive flooding..."


La Nina. What does this have to do with these "studies"?

"The observed change cannot be explained by natural, internal fluctuations of the climate system alone."

So the can partially be explained by *known* factors of this sort and rather than accept that there may be unknown ones, drop the blame on man.

"Global warming likely doubled the odds that such an event would occur, they found."
Likely eh? Well you can't argue with research which comes out with such definitive results.

"Two studies, both published in Nature, are among the first to draw a straight line between climate change and its impact on potentially deadly and damaging extreme weather events."
The fact that they have done nothing of the sort doesn't mean you need to let an oportunity to show flood damage from La Nina events go to waste, does it?
Sean_W
1.9 / 5 (18) Feb 16, 2011
WOLF!!!!!!!!!
(Sorry, did I say that already?)
Pete83
2.1 / 5 (11) Feb 16, 2011
I have to agree with Sean on this. Yes, one can say that humans have had an effect on the climate, of course we have. But the article here is full of ifs, buts, and maybes, and they even go so far as to call it "global warming" not "climate change". For people who understand science, it's all pretty irrelevant. The problem is that the unthinking masses of the world (i.e uneducated westerners), are simply unable to make sense of the information being presented to them, and on top of this, the media giving them this information has zero scientific understanding as well.

We really need some kind of "department of critical thinking", and until you get your "thinking certificate/license", you are banned from expressing opinions in public... Ok... that won't work... but we need something to keep the idiots quiet and out of the way.

Surely all here at physorg is on board for a bit of intellectual classism? Aren't we?

Yeah...
Sleepy
3.7 / 5 (12) Feb 16, 2011
Who should I put my faith in? Internet forum trolls or international teams of university researchers? Science is difficult!
freethinking
1.8 / 5 (16) Feb 16, 2011
Dont worry, be happy. Real scientists are saying the weather isnt getting weirder. Real research belies the idea that storms are getting more extreme. Sorry global warmer believers, your fears are irrational.

add the http:// to the link below and paste into your browser to get a wall street journal article
online.wsj.com/article/SB10001424052748704422204576130300992126630.html
Pete83
2.3 / 5 (9) Feb 16, 2011
Who should I put my faith in? Internet forum trolls or international teams of university researchers? Science is difficult!


Usually I would commend such a comment, but I do not see any kind of trolling in the comments above your comment...

Comment...
Doom1974
3.3 / 5 (7) Feb 16, 2011
Real scientists??? And you quote wall street journal??? That's some reputable scientific journal. Nothing to do with capitalism and bankers and low cost and screw the environment if it is for the profit.

Science denialists quoting "Real Scientists". Nothing hypocritical there....As long as the science suits us. Let me see the next peer reviewed journal with decades of real data from satellites or otherwise that contradict the main stream view of a warming world due to CO2 and then we can discuss.
omatumr
1.7 / 5 (12) Feb 16, 2011
Would it be okay to quote former President Eisenhower, who warned in his farewell address that government science might one day be corrupted this way:

youtube.com/watch?v=GOLld5PR4ts

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
techieatwork
4.1 / 5 (11) Feb 16, 2011
Weather changes, global warming, is driven by human activity, undeniably. We humans keep dumping CO2 on the atmosphere and oceans, we humans keep knocking down rain-forests, and replace them with cattle food plantations, we humans keep reproducing like rabbits, we humans transport our food from one continent to the other (more CO2 dumped on the environment) instead of having organized local farming, we humans dig out any metal from the Earth, just for stupid profits, we humans don't see the logical links between these sub-systems connecting all the dots.. We human are stupid overall. It's not smart to do things this way. It's not smart to have million human below poverty line. It's not smart to over-populate, regardless of the low standard of living for the majority. It's not logical to pay deaf ears to the evidence. All for the profits (virtual worth provided by us in the heads, to metal or paper tokens, or just digital numbers flowing from one bank to the next). Shame on this race.
NotParker
2 / 5 (20) Feb 16, 2011
The IPCC prediction more droughts. When flooding occurs "Climate Charlatans" claim it was caused by global warming.

The IPCC predicted less snow. Now that more snow is occurring, Al Gore claimed that global warming actually causes more snow.

The truth is that the nutbars claim it global warming causes pretty much everything. Which means it actually causes nothing.
Pete83
1 / 5 (5) Feb 16, 2011
Shame on this race


I like your style techieatwork. Please tell me you've seen Zeitgeist: Moving Forward?

(I try to reference the movie in 1 out of every 3 posts I make here)...
kaasinees
3.9 / 5 (8) Feb 16, 2011
The IPCC predicted less snow. Now that more snow is occurring, Al Gore claimed that global warming actually causes more snow.


More snow?! Where the hell did u get that information? Its true in some places theres more snow now, but what is the global measurement of snow??? Also here in the netherlands we used to be PACKED with snow every winter. last 5 years was just a pinch of snow for a few days or weeks.
Pete83
4.4 / 5 (7) Feb 16, 2011
More snow?! Where the hell did u get that information? Its true in some places theres more snow now, but what is the global measurement of snow??? Also here in the netherlands we used to be PACKED with snow every winter. last 5 years was just a pinch of snow for a few days or weeks.


ARGH!!!! This is the problem with this discussion! People seem to think that their local weather is in some way representative of climate change. It isn't!

(sarcasm) I live in Australia, and we just had our best snow season last season of the last decade, so therefore "global warming" MUST be wrong! (/sarcasm)

To have any understanding of the overall climate, one must look at the overall picture. Isn't that really really really really really obvious?

Obviously it's not to many many people.

Besides this, who cares what the models say? You can't pump out as much waste as us humans have and not have some kind of effect on the environment.
kaasinees
3 / 5 (4) Feb 17, 2011
You cant read, can you?

kaasinees:
but what is the global measurement of snow?
looseyarn
2 / 5 (4) Feb 17, 2011
yay, God won't flood us again, it's us.
joefarah
1.4 / 5 (9) Feb 17, 2011
So in the last 10 years we finally have a direct evidence (which is not direct). I would guess, given that it was so hard to find a correon, that if you took 1000 random factors (other than AGW models) you would find one that correlates better.

By the way, did you know that snow causes colder temperatures. Check it out for yourself, everytime there is snow on the ground, the temperature is cold. QED. Solid evidence. Proof. Now we know for a fact that snow causes colder temperatures. So if we want warmer weather, all we have to do is heat the sidewalks and streets when it snows.
joefarah
1.9 / 5 (13) Feb 17, 2011
By the way, please don't mention the 100-year snowfall record broken this week in Korea, or the record levels of snowfall in Boston, nor the cold, snowy winters in the U.K. and the rest of Europe. Also, please ignore the article that said 80% of the US mainland was covered with snow, or the exceptionally long sub-freezing streak in Ottawa Canada this year. Forget the record snow that caused the Metrodome to collapse and all these other "cold" events. These might suggest that there is not Global Warming... whoops, I take that all back, I forgot that Global Cooling is caused by Global Warming - how silly of me.
omatumr
1.4 / 5 (10) Feb 17, 2011
Dogmatic climatologists and dogmatic religionists, are identical twins hiding under different cloaks of respectability.

"Truthing" - seeking a better understanding through:

a.) Highly disciplined scientific experiments, and/or
b.) Highly disciplined mediation and prayers,

Are both processes of ego reduction - if we are honest with ourselves and admit that we never have the "whole truth".

Honest, disciplined "truthing" generates humility and reverence.

If we think we have "the whole truth" or "a complete understanding of God", then we have failed.

There is little or no difference between arrogant, dogmatic climatologists of the 20th and 21st Century and the religionists who blocked the heliocentric findings of Copernicus and Galileo in the 16th and 17th Century.

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo

freethinking
1.9 / 5 (9) Feb 17, 2011
Climate changer believers like to have it there way no matter what. Weather gets warmer in one location, global warming, Weather is colder in one area, weather is not climate, weather is colder, if there is more rain, less rain, more snow, less snow, it is all either climate change caused by man, or if it goes against what they believe its local weather.

Climate changer prophets have been caught in out right lies, but it doesnt matter. They are hypocrites, it doesn't matter. To climate changer believers humans are the cause of any change in weather because they say so. Lemmings the cliff is over there, just follow Gore.
omatumr
2 / 5 (8) Feb 17, 2011
Climate changer believers like to have it there way no matter what.


You are right. Dogmatic scientists have copied from the dogmatic religionists that tried to block evidence of a heliocentric solar system in the 16th and 17th Century.

I suspect that a merger of science and spirituality will be required if we are to survive as a self-governing people.

Doom1974
4.3 / 5 (6) Feb 17, 2011
No need for spirituality. We see what that does to uneducated, easily manipulated people. Some dude exploits it and becomes the prophet and supreme leader of their religion.

By the way, local snow in the northern hemisphere has nothing to do with a spatial and temporal average. Get it? space and time averaged!! what a difficult notion.
Egleton
2.3 / 5 (3) Feb 20, 2011
There is no scientific evidence that smoking is harmful.
Leading Dr.'s recommend Low Tar Lucky Strike.

eerm. What year is this?
Groundhog day.
omatumr
1.7 / 5 (6) Feb 20, 2011
No need for spirituality. We see what that does to uneducated, easily manipulated people.


Religion: "Once upon a time, God made everything . . ."
Science: "Once upon a time nothing exploded into everything . . ."

What is the difference?
ubavontuba
2 / 5 (8) Feb 20, 2011
I remember a time (not more than a few years ago) when it was called "Global Warming." It just so happened we were in a long, relatively dry cycle with low rainfalls and drought reported around the world. This brought about dire predictions of permanent drought and desertification due to Global Warming!

Then, 2009 rolled out and the climate cycle switched to being generally wetter and colder. So now they changed the name to "Climate Change" and are now predicting catastrophic flooding and deep snow!

I wonder, will they go back to the original predictions when the clime oscillates again?

Ho Hum, ya-a-awn. Wake me up when the glaciers are at my door, please.
GSwift7
2.8 / 5 (5) Feb 22, 2011
This study is getting some serious criticism from the experts. There are some big questions about the methods they used. There is a detailed review over at Watts Up With That, and all the big name skeptics are questioning it too. They have some good points. Look them up for yourself and decide what you think about it.