Mails U-turn coverage of link between extreme weather and climate change
Much was written about the potential links between extreme weather events and manmade climate change last week, with Scientific American publishing a three-part special on the topic, followed by an article in the Independent entitled:
“Extreme weather link ‘can no longer be ignored'”
The main gist of these articles was that the emerging science of ‘climate attribution’ is helping researchers determine the likelihood that human activity has influenced a particular extreme weather event.
The Daily Mail‘s Mail Online had quite a different take on the story, however, with its own article based on the Independent piece headlined:
“Global warning: Scientists in U-turn as they claim extreme weather and climate change are linked”
In adapting the story, the Mail have managed to give quite a misleading representation of what it’s about. First up, the headline implies scientists previously denied any link between climate change and extreme weather events, something which is clearly not true. The scientific community has said for a long time that an overall increase in extreme weather events is ‘consistent’ with climate change projections.
The issue has been one of discussing specific events – an actual flood, or a particular heatwave. Here, because extreme weather events are often caused by natural variation in the climate, scientists haven’t made conclusive statements about things ‘being caused by climate change’ because there hasn’t been enough evidence to support doing so.
So it’s a relatively new thing for climate scientists to suggest linking individual extreme weather events and climate change, but there is no evidence ruling out a link between more extreme weather and climate change in general. Indeed some scientists have been pointing out the links for quite some time. Kevin Trenberth for example, head of the Climate Analysis Section at the National Center for Atmospheric Research, has said:
“â?¦ What I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.”
Unfortunately, as well as giving the piece an overly-strong headline, the Mail article also totally overplays the new scientific stance:
“Climate change is inextricably linked to the extreme weather that has wreaked destruction all over the world in the last ten years, scientists now claim.
“Experts are convinced of a legitimate link between the two after more than 20 years of reluctance to blame greenhouse gas emissions for the heavy storms, floods and droughts which have made global headlines.”
Again, this isn’t the case. Only some specific extreme weather events have been attributed in part to manmade climate change. So for example, Dr Peter Stott of the Met Office and a team of researchers found that the likelihood of the devastating heatwave that hit Europe in 2003 was very likely to have been doubled by human activity. But on the other hand, the Russian heatwave of 2010 was found to result largely from natural climate variation by US research institution NOAA – not necessarily influenced by human activity.
Clearly the situation is not as straightforward as it is presented. Some specific extreme weather events are more likely to occur as a result of man-made climate change. Others can’t yet be attributed to human activity, and may never be. It’s an emerging scientific field, not a ‘U-turn’.
The unfortunate thing about these kinds of articles is that they give the misleading impression that scientists are always making big, definite statements about what we do and don’t know, when the reality is that scientists are generally much more cautious about their conclusions.