Let’s talk about the weather. It’s been terrible. In northern Europe, summer has so far been a wash out. Russia has seen disastrous and deadly flooding. Last week I was in China and there was a different extreme: heatwaves across Beijing and Hong Kong. But in central China intense rainfall caused landslides that obliterated villages. It has been a year of such extremes. In Britain, there were record maximum temperatures in March, followed by the wettest April on record, and the equal-wettest June since 1766 (tied with 1860). For this year, the wet summer looks set to continue.
Weather should not be confused with climate (at least that is the correct response to climate change deniers, who like to say that cold weather “disproves” global warming). But can the current weather extremes be directly attributed to global warming? The official and scientific response is that they cannot, but changes in the climatic pattern can (that’s why they call it climate change). EU Climate Action Commissioner Connie Hedegaard, speaking at a European Policy Centre event (10 July) said that “it’s important that we do not mix weather and climate,” but added that “I can see [climate] developments that support that something is changing,” with heavy precipitation, floods and grey summers in northern Europe becoming the new normal, in line with climate scientists’ predictions.
It is unfortunate that the link between global warming and weather cannot be made, or that no-one wants to make it. It would be much easier to quantify the damages from climate change if particular weather events could be attributed to global warming.
For example, the November 2009 floods in Cumbria, northern England, caused by unprecedented heavy rainfall, resulted in insurance payouts of about £175 million (€220 million). Damages from current and recent flooding in the UK will be of a similar magnitude. The most expensive insured event in Europe in 2011, according to the Swiss Re sigma study, was flash flooding in Copenhagen in July, which caused damages of $0.8 billion (€0.65 billion). But though such events are becoming more frequent and more intense, and though intuitively they seem to be a consequence of climate change, we have to hold back from saying that they are.
Quantified and attributed damages assessed on a regular basis would focus attention, possibly even in Poland, on the need for governments to do much more in the face of climate change. We are only at the beginning of a process of climate change, caused, so far, by a relatively limited temperature rise. May 2012 was the warmest May on record, according to the US National Oceanic and Atmospheric Administration, with an average global surface temperature of 0.66°C above the twentieth century average. If, as seems likely under the current little- or no-action scenario, the global temperature rises by 3 or 4 degrees by the end of the century, events such as the July 2011 Copenhagen floods will happen much more frequently, and the economic costs will rapidly mount.
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Just as Commissioner Hedegaard was saying that specific weather events cannot be attributed to climate change, scientists were saying they can. The UK Met Office published research (10 July) that “for the first time… includes so-called ‘climate attribution studies’, looking at six key weather events shortly after they have happened”. For example, global warming means that “the extreme warm average temperature in November 2011 is 60 times more likely to have occurred than in the 1960s,” though not all weird weather can be similarly attributed to climate change, the scientists said.