Climate change: storm in a teacup?

Global warming could have caused Super Typhoon Haiyan, but scientists warn that worse weather is coming

ELLE Segayo had travelled to the central Philippines to teach local officials how to adapt to a future altered by climate change.

But the future, or at least a forewarning of it, came to her instead in the shape of Super Typhoon Haiyan, underlining concerns that damaging storms could increasingly threaten coastal nations such as the Philippines as oceans warm and seawater levels rise.

Scientists have cautioned against blaming individual storms such as Haiyan on climate change. But they agree storms are likely to intensify.

“It’s just about impossible to attribute a specific extreme event to climate change,” said Kevin Walsh, an associate professor of earth sciences at the University of Melbourne.

But “a fair amount of work has been done that suggests the likelihood of extreme tropical cyclones like Haiyan is likely to increase around the world”.

As Haiyan bore down, Segayo, a member of the Philippine Climate Change Commission, dashed to the airport in Tacloban city to try to get back to Manila. The storm, with winds of 314km/h, the fastest ever recorded as having made landfall, met her there.

“It sounded like a pig being slaughtered,” Segayo said, referring to the noise of the city being torn apart and inundated with surging seawater. “We experienced first-hand what we had been lecturing.”

The monster storm that has killed an estimated 10 000 people in Tacloban alone has thrown a fresh spotlight on climate change. It comes as governments gather in Warsaw, Poland, for the latest round of talks on achieving a global climate pact. Only piecemeal progress is expected.

Major tropical storms – variously called cyclones, hurricanes and typhoons, depending on where they strike – are a hard riddle for climate scientists to solve.

The UN Intergovernmental Panel on Climate Change (IPCC) says it is “more likely than not” that storms will increase in intensity in the coming century.

BAt the heart of the uncertainty is the decades of detailed data of storm behaviour needed to actively plot trends, said Walsh of the University of Melbourne.

But one thing is fairly concrete, said Will Steffen, executive director of the Australian National University Climate Change Institute: Climate change is causing surface waters to warm, which in turn feeds more energy into storms.

“You can’t say that any single event, like the typhoon that hit the Philippines, was caused or even exacerbated by climate change. But you can say with some confidence that we’re loading the dice for more severe storms in the future,” he said.

One area of climate change where there is even more certainty is the rise in sea levels. Higher seas mean that storm surges like the tsunami-like flood that caused much of the devastation in Tacloban will get worse, Steffen said.

At Tacloban, it appears rising sea levels played a small role, contributing to about 5 percent of an estimated 4m storm surge, said Jeff Masters, director of meteorology at the website Weather Underground.

That is based on sea level rises of less than 2cm over the 20th century. The IPCC estimates the coming century could see rises of between 26 and 62cm.

“So we can expect future storms like Haiyan to be even more destructive, due to higher storm surges from sea level rises,” Masters said.

The Philippines has a long history of being lashed by deadly typhoons, although none as intense as Haiyan, which cut across a number of areas including Leyte, Samar and Cebu islands.

While about 20 typhoons strike the country each year, most hit the north along the main island of Luzon.

Concerns over extreme weather have been exacerbated by an apparent shift in location of those storms, which in the past two years have also battered southern regions that rarely if ever experienced the powerful gusts of typhoons.

Bopha, a category 5 typhoon with maximum winds of 280km/h, slammed into Davao Oriental province last December, the first storm to ever hit the province, killing about 600 and leaving thousands homeless in the southern Mindanao region.

Philippines climatologists earlier this year said Mindanao could no longer regard itself as a typhoon-free region after two straight years of strong storms.

Tropical storm Washi hit the western coast of Mindanao in December 2011, triggering flashfloods that killed about 700. Haiyan also grazed Mindanao.

“Before, they almost never reached Cebu and definitely not Davao. Now they are reaching that area,” said Jose Maria Lorenzo Tan, president of World Wildlife Fund Philippines, a local arm of the global conservation group.