Climate change is causing increases in the frequency and severity of heatwaves with consequences for human well-being and planetary health writes Prof Peter Thorne, Department of Geography and Director of ICARUS

Large swathes of Europe, Asia and North America are have just suffered extreme heatwave conditions. We are seeing national monthly, and all time, records falling or under threat, wildfires raging and critical infrastructure failing. Earlier this year, the Indian sub-continent sweltered in oppressive and unprecedented early season heat. Last summer, records were not just smashed but obliterated in the Pacific North West.

Last week we experienced unprecedented heatwave ourselves, with advisories issued by Met Eireann, the questions as to whether these events are due to our emissions of heat trapping gases and whether we are truly prepared become ever more urgent. The link between our emissions of heat trapping gases from the burning of fossil fuels and increased heatwaves is now proven beyond all reasonable doubt. As the Intergovernmental Panel on Climate Change (IPCC) concluded last year, it is unequivocal that human activities have warmed the planet.

That this warming is associated with increases in the frequency and severity of heatwaves has been proven over and over in studying numerous such events. Alarmingly, an increasing number of these events have been proven to have been effectively impossible without human influence. In other words, not only are we loading the dice to roll a six, but we are increasingly adding a seven to the dice.

We also know that this will continue to get worse for as long as we continue to burn oil, coal and gas and emit heat trapping gases from other activities. The frequency of what were once rare events (once in 10 or once in 50 year occurrences) has already increased markedly and their intensity has also increased more quickly than the global surface temperature warming to date.

The change in both frequency and intensity has been greater for the one in 50 year events which are now already happening approximately once a decade. This pattern will just get more severe with additional warming. Worse still, it will do so rapidly. Going from 1.5 to two degrees of warming would have greater impacts than going from one to 1.5 degrees of warming. This is why every bit of warming matters and our every action, or inaction, matters.

The reality is that the negative impacts of heatwaves paint a far more grizzly picture. Indeed, we might be rueing these impacts in the depths of this coming winter. The impacts of a heatwave are felt most acutely by the most vulnerable in society. Our built infrastructure and our public amenities simply are not set up to cope with high heat. It will not just be day time temperatures at play either. The warm overnight temperatures are key, as they do not enable recovery from the elevated daytime temperatures. This leads to very real heat health related challenges, further stretching a health service already overstretched by yet another wave of Covid-19.

It's not just people that will be affected either. The cows, sheep, pigs and chickens on our farms, and our pets, suffer in the heat. Crops will also be stressed by the heat, as will our ecosystems more generally. Ecosystems have evolved to be suitable to the climate that used to be, not the climate we have today nor the climate we are hurtling towards. We are changing the climate in a few short decades, as much as it took thousands of years to change while we transitioned from the last glacial maximum when ice sheets covered swathes of Ireland to our pre-industrial climate. Ecosystems simply cannot keep up.

Coming back to the crops, we have all been obsessed with the impacts of Russia's unprovoked and illegal invasion of Ukraine on global food supply. But extremes of heat this year have done or are doing a real number on productivity across the major breadbaskets of the world, such as India, Europe, North America and China. The food price and feedstock inflation this winter – at a time of acute financial stress across society and the agricultural sector – will not be simply due to the Ukraine war. We live in a global, interconnected world. It's time to get real that heatwaves and other climate extremes in some far off land can have very real impacts on us.

We need to stop framing heatwaves as good news and get real about the fact that they represent a huge challenge. We have to take the steps required to ensure we are as resilient as we can be in a world where heatwaves will be both more frequent and severe. We also must halt our emissions of heat trapping gases as quickly as possible to minimise the change we must adapt to.

It's not for nothing that IPCC in its very recent working group II report concluded that "the cumulative scientific evidence is unequivocal: Climate change is a threat to human well-being and planetary health. Any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all."
 
Prof Peter Thorne, is Professor of Physical Geography (Climate Science) at the Department of Geography, Maynooth University and Centre Director of ICARUS. This piece first appeared on RTÉ Brainstorm, July 2022.