The heatwave currently hitting the UK is claiming lives, melting roads and sparking fires. To measure the extent of this historic heat wave, The duty spoke on Tuesday with Vikki Thompson, a climatologist from the University of Bristol, England, who specializes in extreme heat events.
When was the last time the mercury exceeded 40°C in the UK, as seen on Tuesday?
Never ! before today [mardi], we had never seen temperatures reach 39°C in our weather records. The record therefore jumped almost two degrees. And if you take into account very ancient times, one of my colleagues indicated that these kinds of temperatures had not been observed in the United Kingdom for 170,000 years.
What would have been the probabilities of observing such a heat wave in a pre-industrial climate, without climate change?
This type of event seems completely impossible in a pre-industrial climate. It goes beyond what all models indicate, whether those models are statistical or numerical. They failed to assign a probability to it, because the chances of such an event occurring are far too low.
In our current climate, what are the odds? And at the end of the century?
According to a study by the Met Office, the British national meteorological service, published a few years ago, the risks of having a 40°C day in the current climate correspond to once every 200 years. Towards the end of the century, in a scenario where carbon emissions remain high, this would occur every two or three years. In a low-emissions scenario—and I hope we follow such a trajectory—that would happen once every 15 years or so.
Do you think the UK is ready for this? If not, how can the country prepare?
The response to this heat wave shows that we are not ready, that our infrastructures are not ready. Almost all trains in the country have been canceled [mardi] because the rails expand too much at such temperatures. A few airports have suspended operations because the tarmacs have melted. Roads suffered the same fate. Obviously, it is sometimes difficult to adapt the infrastructures. In the United Kingdom, for example, tarmacs must also be able to cope with the cold in winter.
In general, how can an extreme event be attributed to climate change?
Extreme events like the one in Europe and the one in western Canada last year — for which national records were also shattered — are, according to models, completely impossible in a pre-industrial climate. For less extreme events, it is necessary to see if the “return time” [délai moyen entre deux épisodes] predicted by the models has decreased. Perhaps they were possible before, but the frequency with which they have to be expected is increasing in our warming climate.
Forest fires are raging in several European countries. How is climate change altering precipitation on this continent?
Much of Europe has received particularly little rain this year. This has led to droughts in several countries. Depending on climate change, we should expect less rain now, but more intense rains when they occur. The scourge is therefore twofold: we will have droughts, which will cause forest fires, but also very powerful storms, which will cause other problems. All this will increase in the coming decades, unless we reduce our emissions.
Do you think such a heat wave will push British citizens and politicians to commit more strongly to fight climate change?
I fervently hope so. In particular, I hope that governments will start paying attention to this issue and changing certain policies. Not just to adapt, with cooling stations or what it will take to face the heat, but also with strategies to avoid multiplying heat waves in the future, that is to say by reducing our emissions. With any luck, citizens will show with their ballots which avenues they want us to take. We currently have in the UK a leadership race for the Conservative Party, which holds power in London. None of the people who covet this job say anything about climate change. They absolutely must wake up. My comment is not very positive, but right now they are not listening at all.
This text is taken from our newsletter Le Courrier de la Planète.