Fifty years on from the infamous 1976 heatwave, the UK looks set to experience its hottest June day on record – exceeding the maximum of 35.6°C set on 28 June 1976. Extreme summertime heat has quickly become much more common in the UK in recent years. There are myriad ways of demonstrating this, which I won’t repeat here; indeed, many statistics will probably become outdated once again by this week’s heatwave. During a heatwave in August 2020, I wrote a blog taking the reader on a journey through hot British summers. It is sobering to reflect on the extremes which have taken place in the less than six years since.
Nothing brings anthropogenic climate change into focus quite like a record-setting heatwave. It is, after all, the most direct effect of a warming climate. Seeing 40°C show up on a weather app for a UK location, which no one had seen prior to 2022, is an incontrovertible sign that the climate has changed.
So, I’ve been pondering how we communicate climate change. Extreme heat seems to brings this out in me. In July 2018, I tweeted a “1976 vs. 2018” graphic using NASA GISS global temperature anomaly maps to contrast the two heatwave summers. This tweet went viral and ended up printed in the Daily Mail (in an entirely reasonable article on climate change). I am still surprised by this response, because I didn’t think I was showing anything new, but just like Ed Hawkins’ success with the warming stripes, sometimes a simple visualisation goes a long way.
This takes me to a recent discussion with a member of the public on a train journey who had, through casual conversation, found out my occupation. They raised many of the usual points one might come across on social media these days: that it was hotter in the 1970s, that the extreme temperatures we record are due to jet engines, that net zero will bankrupt the country, that there are forces at play to try to control the population through the media, among others. All were things I’d seen or heard before. I responded to each as best I could, and the discussion was friendly enough.
One part of our conversation has been rattling around my head ever since:
“So, do you think if we stop using fossil fuels and do this net zero thing, this will go away?“
“Well, it will stop things getting worse, but it won’t reverse the warming on human timescales… we’ll have to live with that climate unless we take carbon dioxide out of the atmosphere.”
That’s a pretty basic aspect of climate science (and yes, I appreciate that ‘stop things getting worse’ isn’t strictly correct). But that’s not the first time I’ve explained the concept to a non-scientist and realised they didn’t know it or hadn’t quite grasped the implications. The individual looked thoughtful in response, as we arrived at my station and I departed the train – somewhat sad I didn’t get to explain a few things further.
As I walked home processing this conversation, I began to realise that if you think climate change reverses quickly, that “ending global warming” ends all the warmth rather than stopping additional warmth (i.e., that hitting net zero gets you back to our old climate), then it becomes far less of an immediate concern. Why would you prioritise it? One might think: sure, there might be a few more extremes, but we have other pressing things to solve on much shorter timescales, and we can deal with climate change later; it’ll be just as solveable then as it is now.
Of course, that’s not the case: ending global warming means dT/dt = 0, but without negative emissions we essentially end up stuck with the climate at the time we get to dT/dt = 0. Again, a basic point of climate science, but do we say this clearly enough? For everyone who accepts that the temperature is rising because of greenhouse gas emissions, do they appreciate that we’re mostly talking about stopping further rises? That the longer we take to stop the rise, not only the increasingly worse it’ll be between now and then, but the worse it’ll be thereafter, too? Perhaps it is obvious, but if showing maps of 1976 and 2018 side-by-side can prompt such a strong response, maybe some of the basics need re-emphasising.
I’ve concluded that this is a key point I will make in any similar discussions in the future: it’s not just about getting to net zero, but getting to net zero as soon as possible: the warming accumulated by the time we reach net zero is, on human timescales, largely the climate we will then need to live with.
(Blog title is inspired by Bill Bryson’s Notes from a Small Island. With apologies to Bill.)