On last week’s edition of Question Time, former chancellor Nigel Lawson revealed the complacency of the anti-climate change lobby when he refused to concede there was any conceivable link between Typhoon Haiyan and global warming. “Typhon Haiyan is terrible, but I’m afraid these things happen in the tropics,” Mr Lawson commented on the programme, aired last Thursday on BBC1. “If you look at the inter-governmental panel on climate change [IPCC], they say there is absolutely no connection between climate change and tropical storms.”
Most experts agree that there is no real evidence at this stage that climate change is responsible for a greater frequency of cyclonic storms such as hurricanes, cyclones and typhoons. However, contrary to Mr Lawson’s assertion, the IPCC is not so clear-cut as to the details. Indeed, it contains some very illuminating analysis which suggests that the intensity of these storms is increasing as sea temperatures rise. And where uncertainties remain, it is hard to read the report without concluding that this is largely down to the quality of the data.
“More likely than not”
Good data is confined to the North Atlantic, the region including the eastern seaboard of the United States, where hurricanes take place. Here, the document reports low confidence in long-term (i.e. century-long) changes in hurricane activity. However, it also states that it is virtually certain that hurricane activity has increased in the North Atlantic since 1970. And, in its assessment of the probability of future changes, the report states once again that, towards the end of the century, it is “more likely than not” that cyclonic storm activity will increase in both the North Atlantic and, crucially, the Western North Atlantic - where typhoons happen.
Now, “more likely than not” is neither here nor there. “More likely than not” means anything over 50% - not a high confidence threshold at all. At its weakest, “more likely than not” is just a tad beyond 50/50. But for me - neither a climatologist nor a statistician - the question is one of context. What is the context in which “more likely than not” is found?
Understanding the context
The context is the rest of the report. The context is this:
Warmer days and nights:
- Since 1950: very likely to have occurred.
- Probability of human contribution: very likely.
- Likelihood of further change in the late 21st century: virtually certain.
- Frequency and duration of heat waves:
- Since 1950: likely to have occurred in large parts of Europe, Asia and Australia.
- Probability of human contribution: likely.
- Likelihood of further change in the late 21st century: very likely.
- Frequency and intensity of heavy rain:
- Since 1950: likely.
- Human contribution: medium confidence.
- Further change: likely.
- Increase in extreme high sea level:
- Since 1970: likely.
- Human contribution: likely.
- Further change: very likely.
I could go on to quote other choice nuggets, such as “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia.” Or “Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850” (particularly interesting given that Mr Lawson repeatedly asserted that global warming had “stopped” over the last fifteen years). Or perhaps my favourite: “Human influence on the climate system is clear.” I could go on, but I’d only bore you.
The need to protect vulnerable communities
This is the context, and it couldn’t be clearer. Typhoon Haiyan took place against a backdrop of likely human-driven climate change in a world in which all the evidence suggests extreme weather events will become more common and more intense. Regardless of the causes of this particular storm, the upshot of the IPCC’s report is that hugely destructive events of the same magnitude will happen more often. And many of them will afflict some of the most vulnerable societies on Earth.
Perhaps more persuasive than any report, however, are the words of Yeb Sano at the climate talks in Warsaw. He spoke movingly of the horror which has touched everyone in the Philippines; including himself: “Up to this hour, I agonise while waiting for word as to the fate of my very own relatives. What gives me renewed strength and great relief was when my brother succeeded in communicating with us that he has survived the onslaught. In the last two days, he has been gathering bodies of the dead with his own two hands.”
To Mr Sano, there is no doubt about the need to act: “This will have profound implications on many of our communities, especially those who struggle against the twin challenges of the development and the climate change crisis. Typhoons such as Haiyan and its impacts represent a sobering reminder to the international community that we cannot afford to procrastinate on climate action.”
Mr Sano’s words are clear. Many of the communities which are worst affected by extreme weather events like Typhoon Haiyan face real development challenges which leave them even more vulnerable when disaster strikes. Extreme weather events will become more common. We cannot simply refuse to make long-term adaptations when today’s evidence is insufficient to prove conclusively that this event or that was caused by global warming. Such an approach can only result in already fragile communities being worn down by successive disasters.
Contingency planning has to start now. Whether that be architects in aid, as has been suggested, or moving communities away from disaster-prone areas, it is simply not acceptable to wait until climate change has been proven beyond doubt to be the culprit. By the time the evidence is overwhelming, thousands more will have lost their lives. Communities such as those in Tacloban and other parts of Leyte; communities on Samar and Cebu and the many other islands that were devastated by Haiyan - to these communities, it is irrelevant whether the typhoon was caused by climate change or not. What is important is that next time disaster strikes, they are prepared.
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