Science panel says weather will become more extreme

WASHINGTON -- Think of the Texas drought, floods in Thailand and Russia's devastating heat waves as coming attractions in a warming world. That's the warning from top international climate scientists and disaster experts after meeting in Africa.

The panel said the world needs to get ready for more dangerous and "unprecedented extreme weather" caused by global warming. The experts fear that without preparedness, crazy weather extremes may overwhelm some locations, making some places unlivable.

The Nobel Prize-winning Intergovernmental Panel on Climate Change issued a special report on global warming and extreme weather Nov. 18 after meeting in Kampala, Uganda. This is the first time the group of scientists has focused on the dangers of extreme weather events such as heat waves, floods, droughts and storms. Those are more dangerous than gradual increases in the world's average temperature.

For example, the report predicts that heat waves that are now once-in-a-generation events will become hotter and happen once every five years by midcentury and every other year by the end of the century. And in some places, such as most of Latin America, Africa and a good chunk of Asia, they will likely become yearly bakings.

And the very heavy rainstorms that usually happen once every 20 years will happen far more frequently, the report said. In most areas of the U.S. and Canada, they are likely to occur three times as often by the turn of the century, if fossil fuel use continues at current levels. In Southeast Asia, where flooding has been dramatic, it is likely to happen about four times as often as now, the report predicts.

One scientist points to this year's drought and string of 100-degree days in Texas and Oklahoma, which set a record for hottest month for any U.S. state this summer.

‘A wake-up call'

"I think of it as a wake-up call," said one of the study's authors, David Easterling, head of global climate applications for the U.S. National Oceanic and Atmospheric Administration. "The likelihood of that occurring in the future is going to be much greater."

The report said world leaders have to prepare better for weather extremes.

"We need to be worried," said one of the study's lead authors, Maarten van Aalst, director of the International Red Cross/Red Crescent Climate Centre in the Netherlands. "And our response needs to anticipate disasters and reduce risk before they happen rather than wait until after they happen and clean up afterward. ... Risk has already increased dramatically."

Another study lead writer, Chris Field of Stanford University, said scientists aren't quite sure which weather disaster will be the biggest threat because wild weather interacts with economics and where people live. Society's vulnerability to natural disasters, aside from climate, has also increased, he said.

Field said "it's clear that losses from disasters are increasing. And in terms of deaths, "more than 95 percent of fatalities from the 1970s to the present have been in developing countries," he said.

Losses are already high, running at as much as $200 billion a year, said Michael Oppenheimer of Princeton University, a study author.

Science has progressed so much in the last several years that scientists can now attribute the increase in many of these types of extreme weather events to global warming with increased confidence, said study author Thomas Stocker at the University of Bern.

Scientists were able to weigh their confidence of predictions of future climate disasters and heat waves were the most obvious. The report said it is "virtually certain" that heat waves are getting worse, longer and hotter, while cold spells are easing.

The report said there is at least a 2-in-3 chance that heavy downpours will increase, both in the tropics and northern regions, and from tropical cyclones.

The 29-page summary of the full report -- which will be completed in the coming months -- says that extremes could get so bad at some point that some regions may need to be abandoned.

Such locations are likely to be in poorer countries, van Aalst said in a telephone interview, but the middle class may be affected in those regions, which aren't specifically identified in the report. And even in some developed northern regions of the world, such as Canada, Russia and Greenland, cities might need to move because of weather extremes and sea level rise from man-made warming, he said.

In places like van Aalst's native Netherlands, citizens will have to learn how to handle new weather problems, in this case heat waves.

And it's not just the headline grabbing disasters like a Hurricane Katrina or the massive 2010 Russian heat wave that studies show were unlikely to happen without global warming. At the Red Cross/Red Crescent they are seeing "a particular pattern of rising risks" from smaller events, van Aalst said.

Of all the weather extremes that kill and cause massive damage, he said, the worst is flooding.

There's an ongoing debate in the climate science community about whether it is possible and fair to attribute individual climate disasters to manmade global warming. Usually meteorologists say it's impossible to link climate change to a specific storm or drought, but that such extremes are more likely in a future dominated by global warming.

Jerry North, a scientist at Texas A&M University who wasn't part of the study, said he thought the panel was being properly cautious in its projections and findings, especially since by definition climate extremes are uncommon events. MIT professor Kerry Emanuel thought the panel was being too conservative when it comes to tropical cyclones.

The panel was formed by the United Nations and World Meteorological Organization. In the past, it has discussed extreme events in snippets in its report. But this time, the scientists are putting them together.

The next major IPCC report isn't expected until the group meets in Stockholm in 2013.

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Online:

Intergovernmental Panel on Climate Change: http://www.ipcc.ch/

NOAA on weather extremes: http://1.usa.gov/sYQQRv