- (08 September 2011)
- Published online
- 07 September 2011
Extreme weather makes news, as was demonstrated last month by the blanket coverage of the devastation caused to the east coast of the United States by Hurricane Irene. But was the prominence of the story a feature of modern media hype in a rolling-news world? Hardly. According to a New York Times analysis, when Hurricane Andrew made landfall in Florida in 1992 and killed 22 people, it received twice the traditional news coverage that Irene did.
What is new is that coverage of extreme weather is now often accompanied by a question: is this a consequence of climate change? This question was raised frequently after Hurricane Katrina smashed through New Orleans in 2005. Most climate scientists responded equivocally, as scientists do: climate is not weather, and although all extreme weather events are now subject to human influence, global warming driven by greenhouse gases cannot be said to ’cause’ any specific manifestation of weather in a simple deterministic sense.
“Most people associate the climate with the weather that they experience, even if they aren’t supposed to.”
Is that response enough? The question, after all, seems fair, given the dire warnings of worsening weather that are offered to the public as reasons to care about global warming. It may irritate some scientists, but in fact the question can be seen as a vindication of their efforts to spread the message that the climate problem is a clear and present danger. Most people associate the climate with the weather that they experience, even if they aren’t supposed to. And they are right to wonder how and why that experience can, on occasion, leave their homes in pieces.
Given the growing interest, it is a good sign that scientists plan to launch a coordinated effort to quickly and routinely assess the extent to which extreme weather events should be attributed to climate change (see page 148). The ambitious idea is in the early stages, and its feasibility is yet to be demonstrated. It will require funding, access to climate data from around the world and considerable computer time. Funding agencies and climate centres must provide the necessary support.
As operational climate-attribution systems develop, it is important that they do not remain purely an academic exercise. To reach out to the public, attribution scientists could do worse than to ally themselves with meteorologists — including commercial providers of weather forecasts — to explain how climate change affects the risk of extreme weather. There is, after all, a lot of scope for the makers and presenters of daily weather reports to inform their listeners and viewers more solidly about consequences of climate change than they have chosen to do in the past.
Climate scientists, too, have an obligation to provide more coherent answers to queries (or doubts) as to how global warming influences our weather. An attribution system with ample resources, running in near real time, could prevent scientists’ answers to those questions seeming either too cautious or too alarmist and speculative. It could also prevent the public from getting the (false) impression that climate research is confined to the virtual world of climate models and has little to offer when it comes to current reality, or that climate science is a quasi-experimental field that yields scary but mostly unverifiable results. The service’s broad integration into people’s daily lives, through the old and new mass media, would be a good way to seed greater acceptance of climate scientists’ actual services to society and the problem of climate change.
There are constraints here. Attribution is only as good as the models and statistics that power it — and the various existing climate models project different trends in future extremes in some regions. There is a lack, or poor availability, of long-term observational records, and of climate data with high spatial and temporal resolution. And however it develops, climate attribution will remain rooted in probabilities. Not even the most thorough study can work out with absolute confidence the exact fingerprint of global warming in a given weather event.
What about Irene, then? A concerted attribution effort should help to resolve, in the not-so-distant future, the ongoing controversy over the effect of climate change on hurricane formation. Whatever the result, if the exercise can prevent people from building houses along the most vulnerable coastlines, it will be worth the effort.