Early warning system

“We’ve been telling the rest of the world we don’t want what’s happening to us to happen to everyone else,” said Lucille L. Sering, the vice chair of the Philippines’ Climate Commission,, as the country struggled to cope with the aftermath of Typhoon Haiyan. “This is your early warning system...we will all eventually be victims of this phenomenon.”

A full week after the typhoon roared through the eastern Visayas, the number of people killed is still unknown. Ten thousand dead is the number being used in the media, but the area around Tacloban city alone may have lost that many. Many other parts of Samar and Leyte islands are still inaccessible to both media and aid workers.

But the question that people will be asking elsewhere is: will we really all become victims of this and similar phenomena? Is this truly an early warning of storms so big and strong that they will change the way we live? The answer, of course, is maybe.

As scientists always hasten to explain, you can never attribute a particular weather event to climate change with complete confidence. Normal variations in the weather include occasional extreme events as destructive as all but the very worst storms that you would see in a world that was, say, 2 degrees C (3.5 degrees F) warmer. The difference is that in a warmer world, you will see a lot more of these extreme events.

But consider this. The Philippines is the most-exposed large country in the world to tropical cyclones. Their tracks most often take them across northern Luzon or the eastern Visayas, and about six to nine of them make landfall each year. They do a lot of damage, but by and large Filipinos have learned to ride them out. However, you cannot just ride out something as big as Haiyan.

What did most of the killing in Samar and Leyte last week was not the high winds (although they stripped off almost every roof in the affected areas). It was the “storm surge” that submerged coastal regions to the height of a two-story building. The pressure at the centre of the typhoon was so low that a “hump” of water 6 metres (20 ft.) high was pushed up beneath the eye and travelled with it.

Shelters are not much good against that sort of thing unless (as in Bangladesh) you start building them on elevated platforms. Even then, you may decide that you want to move elsewhere if your city is going to be inundated and destroyed every ten years or so. The east coast of Luzon is very sparsely populated for precisely this reason, and this may be the future that awaits the eastern Visayas as well if storms of this scale become more frequent.

The very worst typhoon that hit the Philippines since detailed records began in the 19th century was Thelma, which killed about 5,100 people in 1991. But of the next worst nine, all of which killed over a thousand people, six have happened in the past decade: 2004, 2006, 2008, 2011, 2012, and 2013.

So Haiyan may really be an early warning of what is to come, not just for the Philippines but for China and Japan, Burma and Bangladesh, the Windward Islands and Florida – indeed, for any coastal area that is within a thousand km. (500 miles) of the usual tracks of tropical storms. And at some point, people will decide that it’s just not worth living in such constant danger. They will become, for want of a better word, “climate refugees”.

In some areas, it will be frequent mega-storms that drive them out. In other areas it will be drought and desertification, or heat so great that it kills the crops that people depend on. There are going to be a lot of refugees, and not many places that are willing to let them in.

Lucille Sering is right: this is an early warning of how the warming will unfold, and what the impacts on human societies will be. But we are getting lots of early warnings, and so far we are managing to ignore them all.