Heatwaves and climate change: A cooler look

So it’s all done and dusted, then. Northern Europe has had a huge heatwave – science has shown that climate change made it more likely to occur – and so we should loudly proclaim ‘this is climate change, people’.

Right?

Er – no. Not in my view, anyway.

Lest you think I’ve had an attack of the Ridleys, let me explain. I’ve written here before that one hot year doesn’t ‘prove’ climate change… because logically, if it does, then one cold one disproves it. And if a hot year doesn’t prove climate change, then one heatwave in one part of the globe certainly doesn’t.

You may quibble with ‘one part of the globe’ – and that’s fair. The northern European heatwave has coincided with a remarkable number of events in other parts of the world too. Japan, Algeria, Oman, California … all have seen extraordinary heat in recent weeks, the first two breaking national records and the third setting what is believed to be the hottest temperature at the daily minimum (night-time) recorded anywhere in the world.

The point is… that still leaves a heck of a lot of the world where records aren’t being broken.

In Europe, for example, attention has naturally focussed on the tragic wildfire at Mati in Greece and the blazes north of the Arctic Circle in Sweden. But the area consumed by wildfires across the continent as a whole is actually below average this summer.

That’s because the two countries that usually have the most conflagrations, Spain and Portugal, saw early summer weather a little cooler and wetter than normal.

Delving into the global temperature data, you see also that 2018 is not going to set any records. The first half of the year has been cooler than 2017, 2016 and 2015 – very similar, in fact, to 2014. That other totemic marker of climate change, Arctic sea ice, also appears unlikely to set any records this year – the July report from the National Snow and Ice Data Center reports that ‘…the rate of summer ice loss has been unremarkable thus far.’

So here’s the issue. If you nail your colours to the mast of the heatwave, and proclaim that it ‘proves climate change is here’, or some variant of the phrase – then what are you going to say later in the year, when reports start to emerge showing that globally – or even regionally, bearing in mind the caution above about Spain and Portugal – 2018 wasn’t that remarkable?

The thing is – to prove that climate change is real, you don’t need to cite any given heatwave. You don’t have to base your argument on a drought or a hurricane or a flood. There is abundant evidence already in the long-term records of myriad indicators, from thermometers in weather stations to the migration of plankton, for it to be beyond dispute.

Right end of the telescope

The approach that scientists are using to greater and greater effect is to look at it from the other way round, and investigate the links from the climate change we know is happening to its individual manifestations.