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FEATURE: Super Typhoon Haiyan: the climate connection

Dr Maarten van Aalst, Director of the Red Cross Red Crescent Climate Centre, discusses the link between the Super Typhoon and climate change.

People in the Philippines who track climate news won’t have failed to notice that it was almost a year ago, just as the 2012 round of UN climate talks drew to a close in Qatar, when Typhoon Bopha wrought havoc on the island of Mindanao.

People in the Philippines who follow climate news won’t have failed to notice that it was almost a year ago, just as the 2012 round of UN climate talks drew to a close in Qatar, when Typhoon Bopha wrought havoc on the island of Mindanao.

Now Typhoon Haiyan has struck the country just three days before the UNFCCC COP 19 talks began in Warsaw, where delegates from almost 200 nations observed three minutes’ silence, and the Philippine representative, Naderev Sano, said he was beginning a fast in protest at the lack of international action on climate change.

Like Haiyan last week, Bopha made landfall as a Category 5 “Super Typhoon”; it was the strongest storm to hit the country last year; Bopha also was unusual in tracking close to the equator and affecting an area of the country normally outside the typhoon belt.

Inevitably and rightly, people ask: is this climate change?

There is little doubt that, judged by wind speed alone, Haiyan is one of the fiercest storms ever recorded, and it may turn out to be one of the very strongest ever to make landfall anywhere in the world.

‘Climate signal’

A difficulty scientists will face in making emphatic statements just about the intensity of this storm is that unlike in the North Atlantic, there is no aircraft reconnaissance of typhoons in the Western Pacific. So actual wind speed and air pressure – the parameters by which storms are classified – must be gauged from satellite imagery.

In contrast to some other climate impacts – like heatwaves in Europe, for example – experts on the Intergovernmental Panel on Climate Change now express only “low confidence” of long-term increases in tropical cyclone activity, judged by intensity, frequency and duration.

What we sometimes refer to as the “climate signal” with hurricanes, cyclones and typhoons (they are all the same thing: intense tropical low-pressure systems) is soft, in other words.

In addition, the standing caveat applies with Haiyan as it does with all other impacts: no single extreme-weather event can ever be attributed directly to climate change, which applies to averages and long-term trends.

The grounds for saying that storms like Haiyan “are climate change” are relatively weak, but last year we at the Climate Centre said Typhoon Bopha fitted “a pattern of generally rising risk of extreme-weather events” that humanitarians must be aware of and prepare for; we reiterate that now.

A good source on this question, the Climate Central website, said yesterday that: “Based on the scientific literature…Haiyan’s intensity [emphasis added] was not a clear-cut sign of manmade global warming.”

But it also points out that while much of the focus has been on the storm’s intensity, a much less heavily publicised factor is rapidly gaining in significance: the deadly sea surge, possibly as high as three metres, that made this disaster resemble the aftermath of a tsunami – especially when seen from the air.

This is the wave that moves ahead of a storm system, given momentum and force by the combination of high wind speed and extremely low atmospheric pressure. (It’s also possible that the surge that hit Tacloban City was amplified by local topography.)

Aerial images of Tacloban show clearly that the very worst damage is along the seafront – as would be the case with a tsunami.

Although the Philippine Red Cross was able to report that hundreds of thousands of people were successfully evacuated, there’s some reason to believe that many others, reluctant to abandon their property, tried to sit out the storm indoors and were swept up in the surge.

Here, the climate signal becomes much louder, with rising sea-levels setting a higher baseline for any surges that do develop as part of storm systems, similar to the dramatic impacts faced by New York City when it was it by Hurricane Sandy last year.

It’s far too early to come to any firm conclusion about exactly why the losses have been so great in this place at this time. But it will be asked why a storm billed by the media at least 24 hours in advance as a “monster” can track in an almost dead straight line, precisely as forecast, before obliterating a city of nearly a quarter of a million people.


We in the humanitarian sector must persevere with our familiar messages about the preparedness that has worked well and saved countless lives in countries like Bangladesh, India, Mozambique, Nicaragua and – certainly on earlier occasions and perhaps even with this disaster – the Philippines.

Preparedness, that is, on the shortest timescales, with emergency evacuation ordered, possibly even compelled, by the authorities; on medium timescales with work like the pre-positioning of relief supplies for hurricane seasons; and in the longer term with “disaster risk reduction” in all its forms.

After the humanitarian needs are met and the dead have been properly mourned, the Philippine people will ask themselves how well they did on the vital preparedness front, and what could have been done better. After any disaster anywhere, there are always lessons to learn.

From the humanitarian perspective, some of the biggest gaps in our knowledge are probably not related to climate science or weather prediction at all, which are getting steadily more reliable, but to information on human exposure and vulnerability.

The sad truth is that we must now invest more in understanding the limits of preparedness for the extreme and unusual events, of whatever character, that may now multiply – including thresholds beyond which we know we will simply face a humanitarian disaster. This is a major challenge for both humanitarian action and development planning.

Typhoon Haiyan seen from space approaching its deadly landfall in the central Philippines late last week. (Photo: Eumetsat via Twitter)

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