* Extreme weather events become more frequent
* Impossible to blame warming for individual events
* 2010 on track to be warmest year since records began
Alister Doyle, Reuters AlertNet 9 Aug 10;
OSLO, Aug 9 (Reuters) - Devastating floods in Pakistan and Russia's heatwave match predictions of extremes caused by global warming even though it is impossible to blame mankind for single severe weather events, scientists say.
This year is on track to be the warmest since reliable temperature records began in the mid-19th century, beating 1998, mainly due to a build-up of greenhouse gases from fossil fuels, according to the U.N. World Meteorological Organization (WMO).
"We will always have climate extremes. But it looks like climate change is exacerbating the intensity of the extremes," said Omar Baddour, chief of climate data management applications at WMO headquarters in Geneva.
"It is too early to point to a human fingerprint" behind individual weather events, he said.
Recent extremes include mudslides in China and heat records from Finland to Kuwait -- adding to evidence of a changing climate even as U.N. negotiations on a new global treaty for costly cuts in greenhouse gas emissions have stalled.
Reinsurer Munich Re said a natural catastrophe database it runs "shows that the number of extreme weather events like windstorm and floods has tripled since 1980, and the trend is expected to persist".
The worst floods in Pakistan in 80 years have killed more than 1,600 people and left 2 million homeless.
"Global warming is one reason" for the rare spate of weather extremes, said Friedrich-Wilhelm Gerstengarbe, a professor at the Potsdam Institute for Climate Impact Research.
DOWNPOURS
He pointed to the heatwave and related forest fires in Russia, floods in Pakistan, rains in China and downpours in countries including Germany and Poland. "We have four such extremes in the last few weeks. This is very seldom," he said.
The weather extremes, and the chance of a record-warm 2010, undercut a view of sceptics that the world is merely witnessing natural swings perhaps caused by variations in the sun's output.
Russia's worst drought in decades has led to fires that have almost doubled death rates in Moscow to around 700 per day, an official said. Prime Minister Vladimir Putin announced a grain export ban from Aug. 15 to Dec. 31.
Nearly 1,500 people have died in landslides and flooding caused by months of torrential rains across China, the Ministry of Civil Affairs said.
Baddour said one cause of a shift in monsoon rains in Asia seemed to be a knock-on effect of La Nina, a natural cooling of the Pacific region.
Scientists say it is impossible to pin the blame for individual events from hurricanes to sandstorms solely on human activities led by burning of fossil fuels that release heat-trapping carbon dioxide.
Still, one study concluded that global warming had doubled the chances of heatwaves similar to a scorching 2003 summer in Europe, in which 35,000 people died. Those temperatures could not convincingly be explained by natural variations.
"It may be possible to use climate models to determine whether human influences have changed the likelihood of certain types of extreme events," the U.N. panel of climate scientists said in its latest 2007 report.
That report said it was at least 90 percent likely that most warming in the past 50 years was caused by mankind, a finding questioned by sceptics who have pointed to errors in the report such as an exaggeration of the melt of Himalayan glaciers.
"Warming of the climate is likely to bring more events of this sort," said Henning Rodhe, professor emeritus of chemical meteorology at Stockholm University, of the Russian heatwave.
"But you can't draw the conclusion that this is caused by global warming."
Most countries agreed at a U.N. climate summit in Copenhagen last year to limit a rise in average world temperatures to below 2 degrees Celsius above pre-industrial times, a tough goal since temperatures already rose 0.7C in the 20th century.
The latest round of U.N. climate talks in Bonn, from Aug. 2-6, ended with growing doubts that a global climate treaty could still be agreed as hoped by some nations in 2010 despite deep splits about sharing the burden of curbs on emissions.
U.S. Senate majority leader Harry Reid has all but abandoned climate change legislation this year. The United States, the number two greenhouse gas emitter behind China, is the only major industrialised nation with no law to cut emissions.
Extreme weather fuels debate over global warming
Anne Chaon Anne Chaon Yahoo News 9 Aug 10;
PARIS (AFP) – As Russia battles wildfires triggered by an unprecedented heatwave, flood waters surge across a drenched Pakistan leaving millions of people homeless, and questions are asked about global warming.
Extreme weather has been a feature of the summer of 2010, with floods in Pakistan, China and Eastern Europe seemingly matched by heatwaves in Western Europe and Russia.
However, experts interviewed by AFP Monday were cautious over offering the events as proof of a changing climate, saying that while they fit with climatic projections in a warming planet, one extremely dry -- or wet -- summer isn't sufficient evidence in isolation.
"One cannot conclude 100 percent that nothing like this has happened in the past 200 years, but the suspicion is there. Even if it's only a suspicion," said Jean-Pascal van Ypersele, vice-president of the Intergovernmental Panel on Climate Change (IPCC), which has tracked the impact of human activity on climate for the past 20 years.
"These are events which reproduce and intensify in a climate disturbed by greenhouse gas pollution," he said.
"Extreme events are one of the ways in which climatic changes become dramatically visible."
The planet has never been as hot as it has been in the first half of this year, the US National Oceanic and Atmospheric Administration said in a July report.
According to the IPCC, droughts and heatwaves likes those affecting Russia and 18 US states become longer and more intense in a warming planet.
"Whether in frequency or intensity, virtually every year has broken records, and sometimes several times in a week," said Omar Baddour, who tracks climate change for the World Meteorological Organisation.
"In Russia, the record temperature in Moscow (38.2 degrees Celsius, 100.8 degrees Farenheit in late July) -- which had not been seen since records began 130 years ago -- was broken again at the start of August. In Pakistan, the magnitude of the floods is unheard of," he said.
"In both cases, it is an unprecedented situation. The succession of extremes and the acceleration of records conform with IPCC projections. But one must observe the extremes over many years to draw conclusions in terms of climate," he said.
The floods in Pakistan could be caused by La Nina -- the inverse of the El Nino phenomenon, which it generally follows -- namely the cooling of surface temperatures in the Pacific ocean, Baddour said.
"In general, El Nino leads to drought in the Indian subcontinent and the Sahel. With La Nina, it is the opposite," said Baddour.
According to British climatologist Professor Andrew Watson, the high temperatures this summer are linked to last year's El Nino.
"We know that in a period following El Nino you got a very hot year globally and that is certainly occuring this year," he said.
Nevertheless, Watson said the extreme events are "fairly consistent with the IPCC reports and what 99 percent of the scientists believe to be happening."
Watson, who is from the University of East Anglia which was at the centre of last year's "climategate" scandal over faked data, was reluctant to leap to any conclusions.
"I'm quite sure that the increased frequency of these kind of summers over the last few decades is linked to climate change," he said
"But you cannot say a single event or a single summer is unequivocally due to climate change -- by definition it's weather, and not climate."
Long, hot summer of fire, floods fits predictions
Charles J. Hanley, Associated Press Yahoo News 13 Aug 10;
NEW YORK – Floods, fires, melting ice and feverish heat: From smoke-choked Moscow to water-soaked Iowa and the High Arctic, the planet seems to be having a midsummer breakdown. It's not just a portent of things to come, scientists say, but a sign of troubling climate change already under way.
The weather-related cataclysms of July and August fit patterns predicted by climate scientists, the Geneva-based World Meteorological Organization says — although those scientists always shy from tying individual disasters directly to global warming.
The experts now see an urgent need for better ways to forecast extreme events like Russia's heat wave and wildfires and the record deluge devastating Pakistan. They'll discuss such tools in meetings this month and next in Europe and America, under United Nations, U.S. and British government sponsorship.
"There is no time to waste," because societies must be equipped to deal with global warming, says British government climatologist Peter Stott.
He said modelers of climate systems are "very keen" to develop supercomputer modeling that would enable more detailed linking of cause and effect as a warming world shifts jet streams and other atmospheric currents. Those changes can wreak weather havoc.
The U.N.'s network of climate scientists — the Intergovernmental Panel on Climate Change (IPCC) — has long predicted that rising global temperatures would produce more frequent and intense heat waves, and more intense rainfalls. In its latest assessment, in 2007, the Nobel Prize-winning panel went beyond that. It said these trends "have already been observed," in an increase in heat waves since 1950, for example.
Still, climatologists generally refrain from blaming warming for this drought or that flood, since so many other factors also affect the day's weather.
Stott and NASA's Gavin Schmidt, at the Goddard Institute of Space Studies in New York, said it's better to think in terms of odds: Warming might double the chances for heat waves, for example. "That is exactly what's happening," Schmidt said, "a lot more warm extremes and less cold extremes."
The WMO pointed out that this summer's events fit the international scientists' projections of "more frequent and more intense extreme weather events due to global warming."
In fact, in key cases they're a perfect fit:
RUSSIA
It's been the hottest summer ever recorded in Russia, with Moscow temperatures topping 100 degrees Fahrenheit (37.8 degrees C) for the first time. Russia's drought has sparked hundreds of wildfires in forests and dried peat bogs, blanketing Moscow with a toxic smog that finally lifted Thursday after six days. The Russian capital's death rate doubled to 700 people a day at one point. The drought reduced the wheat harvest by more than one-third.
The 2007 IPCC report predicted a doubling of disastrous droughts in Russia this century and cited studies foreseeing catastrophic fires during dry years. It also said Russia would suffer large crop losses.
PAKISTAN
The heaviest monsoon rains on record — 12 inches (300 millimeters) in one 36-hour period — have sent rivers rampaging over huge swaths of countryside, flooding thousands of villages. It has left 14 million Pakistanis homeless or otherwise affected, and killed 1,500. The government calls it the worst natural disaster in the nation's history.
A warmer atmosphere can hold — and discharge — more water. The 2007 IPCC report said rains have grown heavier for 40 years over north Pakistan and predicted greater flooding this century in south Asia's monsoon region.
CHINA
China is witnessing its worst floods in decades, the WMO says, particularly in the northwest province of Gansu. There, floods and landslides last weekend killed at least 1,100 people and left more than 600 missing, feared swept away or buried beneath mud and debris.
The IPCC reported in 2007 that rains had increased in northwest China by up to 33 percent since 1961, and floods nationwide had increased sevenfold since the 1950s. It predicted still more frequent flooding this century.
UNITED STATES
In Iowa, soaked by its wettest 36-month period in 127 years of recordkeeping, floodwaters from three nights of rain this week forced hundreds from their homes and killed a 16-year-old girl.
The international climate panel projected increased U.S. precipitation this century — except for the Southwest — and more extreme rain events causing flooding.
ARCTIC
Researchers last week spotted a 100-square-mile (260-square-kilometer) chunk of ice calved off from the great Petermann Glacier in Greenland's far northwest. It was the most massive ice island to break away in the Arctic in a half-century of observation.
The huge iceberg appeared just five months after an international scientific team published a report saying ice loss from the Greenland ice sheet is expanding up its northwest coast from the south.
Changes in the ice sheet "are happening fast, and we are definitely losing more ice mass than we had anticipated," said one of the scientists, NASA's Isabella Velicogna.
In the Arctic Ocean itself, the summer melt of the vast ice cap has reached unprecedented proportions in recent years. Satellite data show the ocean area covered by ice last month was the second-lowest ever recorded for July.
The melting of land ice into the oceans is causing about 60 percent of the accelerating rise in sea levels worldwide, with thermal expansion from warming waters causing the rest. The WMO'S World Climate Research Program says seas are rising by 1.34 inches (34 millimeters) per decade, about twice the 20th century's average.
Worldwide temperature readings, meanwhile, show that this January-June was the hottest first half of a year since recordkeeping began in the mid-19th century. Meteorologists say 17 nations have recorded all-time-high temperatures in 2010, more than in any other year.
Scientists blame the warming on carbon dioxide and other heat-trapping gases pouring into the atmosphere from power plants, cars and trucks, furnaces and other fossil fuel-burning industrial and residential sources.
Experts are growing ever more vocal in urging sharp cutbacks in emissions, to protect the climate that has nurtured modern civilization.
"Reducing emissions is something everyone is capable of," Nanjing-based climatologist Tao Li told an academic journal in China, now the world's No. 1 emitter, ahead of the U.S.
But not everyone is willing to act.
The U.S. remains the only major industrialized nation not to have legislated caps on carbon emissions, after Senate Majority Leader Harry Reid last week withdrew climate legislation in the face of resistance from Republicans and some Democrats.
The U.S. inaction, dating back to the 1990s, is a key reason global talks have bogged down for a pact to succeed the expiring Kyoto Protocol. That is the relatively weak accord on emissions cuts adhered to by all other industrialized states.
Governments around the world, especially in poorer nations that will be hard-hit, are scrambling to find ways and money to adapt to shifts in climate and rising seas.
The meetings of climatologists in the coming weeks in Paris, Britain and Colorado will be one step toward adaptation, seeking ways to identify trends in extreme events and better means of forecasting them.
A U.N. specialist in natural disasters says much more needs to be done.
Salvano Briceno of the U.N.'s International Strategy for Disaster Reduction pointed to aggravating factors in the latest climate catastrophes: China's failure to stem deforestation, contributing to its deadly mudslides; Russia's poor forest management, feeding fires; and the settling of poor Pakistanis on flood plains and dry riverbeds in the densely populated country, squatters' turf that suddenly turned into torrents.
"The IPCC has already identified the influence of climate change in these disasters. That's clear," Briceno said. "But the main trend we need to look at is increasing vulnerability, the fact we have more people living in the wrong places, doing the wrong things."
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AP Correspondents Michael J. Crumb in Des Moines, Iowa, and Christopher Bodeen in Beijing contributed to this report.
