Link builds between weather extremes and warming

LONDON Sun Mar 25, 2012 2:03pm EDT

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LONDON (Reuters) - Extreme weather events over the past decade have increased and were "very likely" caused by manmade global warming, a study in the journal Nature Climate Change said on Sunday.

Scientists at Germany's Potsdam Institute for Climate Research used physics, statistical analysis and computer simulations to link extreme rainfall and heat waves to global warming. The link between warming and storms was less clear.

"It is very likely that several of the unprecedented extremes of the past decade would not have occurred without anthropogenic global warming," said the study.

The past decade was probably the warmest globally for at least a millennium. Last year was the eleventh hottest on record, the World Meteorological Organization said on Friday.

Extreme weather events were devastating in their impacts and affected nearly all regions of the globe.

They included severe floods and record hot summers in Europe; a record number of tropical storms and hurricanes in the Atlantic in 2005; the hottest Russian summer since 1500 in 2010 and the worst flooding in Pakistan's history.

Last year alone, the United States suffered 14 weather events which caused losses of over $1 billion each.


The high amount of extremes is not normal, the study said.

Even between March 13 and 19 this year, historical heat records were exceeded in more than 1,000 places in North America.

For some types of extreme weather, there are physical reasons why they would increase in a warming climate. For example, if average temperature rises, then so will the number of heat records if all else remains equal, the study said.

Natural weather patterns like El Nino or La Nina can also cause highs in global temperature or increased precipitation which leads to floods.

"Single weather extremes are often related to regional processes, like a blocking high pressure system or natural phenomena like El Nino," said Stefan Rahmstorf, co-author of the study and chair of the institute's earth system analysis department.

"These are complex processes that we are investigating further. But now these processes unfold against the background of climatic warming. That can turn an extreme event into a record-breaking event."

Recent years have seen an exceptionally large number of record-breaking and destructive heatwaves in many parts of the world and research suggests that many or even most of these would not have happened without global warming.

Currently, nearly twice as many record hot days as record cold days are being observed both in the United States and Australia, the length of summer heatwaves in western Europe has almost doubled and the frequency of hot days has almost tripled over the period from 1880 to 2005.

Extremely hot summers are now observed in about 10 percent of the global land area, compared with only about 0.1-0.2 percent for the period 1951 to 1980, the study said.

The link between storms and hurricanes and global warming is less conclusive but at least some of recent rainfall extremes can be attributed to human influences on the climate, it added.

(Reporting by Nina Chestney)

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Comments (6)
Oilbrat wrote:
More conjecture on what is causing global warming when in fact they have no truthful answer. It is interesting how they leave out the ice core facts that indicate earth has had numerous global warming and cooling events over millions of years. They don’t for sure if the cause is here on earth or comes from something in the universe or the sun. Pure speculation based on statistical models for more grant money.

When they have real proof as to what caused past global warming, then they can predict with some truth to what may be causing this one… if there is one or maybe it is statistical errors in their model after all the weather (temperature) is very variable and nearly impossible to measure as it is all about averages over time and sometimes averages of averages given the method of measurement.

Mar 26, 2012 3:04am EDT  --  Report as abuse
The research does not take into account that global warming is happening in the entire solar system not just on earth, for the past few decades all the planets far from the sun (including the sometimes not included as planet but only to some: pluto). This is not just manmade problems, it’s a solar-wide problem.

Mar 26, 2012 12:09pm EDT  --  Report as abuse
Junifer wrote:
Huh. The University of East Anglia recently released a report that said Global Warming ceased in 1997. They were among the first to sound the global warming alarm. I’d like the global warming alarmists to explain why their data doesn’t square with other global warming alarmists. I’d also like them to explain why we should pay attention to their modeling data when NASA’s real-world data says global warming data based on modeling and supposition is exaggerated. We have real science and fake science, with the fake scientists disputing one another and ignoring real-world info.

Mar 26, 2012 9:43pm EDT  --  Report as abuse
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