Climate change is real, and intense and increasing heat waves are part of that reality. But that’s not the end of the story. Here are five things everyone should know about heat waves — some bad news, some surprising news and even some good news.
1) There is a strong climate-change connection, almost everywhere.
Heat waves, like the one breaking temperature records across the United Kingdom and Europe this week, are the weather phenomena scientists have the most confidence in linking to human-caused climate change.
The Intergovernmental Panel on Climate Change used its strongest language in describing heat waves in its latest assessment, stating with virtual certainty that they’ve become more frequent and more intense globally since 1950, with greenhouse-gas emissions the main driver of these changes.
2) The connection is not as strong, however, in the United States.
It will probably come as a surprise to many, but the United States is one of the exceptions to the global trend. The IPCC is far less confident in an upward trend in heat waves in America since 1900, noting that large-scale agriculture and associated irrigation may have contributed to limiting summer hot-weather extremes.
Indeed, the US government’s latest National Climate Assessment concluded that the frequency of US heat waves has increased since the 1960s — but they have yet to reach levels observed during the first 40 years of the last century. And using an index first presented in a paper I co-authored, the US NCA concludes that the intensity of US heat waves remains far below those observed in the 1920s and 1930s. As hot as it is today, it has been worse.
3) No one need die from extreme heat.
Heat waves are common around the world and becoming more common in places that only experienced them rarely, like London. That hard-earned experience means we’ve developed a good understanding of how to keep people safe in extreme temperatures. A recent study of US heat-wave mortality finds a steady decline in risk since the 1970s, even as population has grown and heat-wave incidence has increased.
Looking to the future, even with the IPCC projecting heat waves to continue to increase, the World Health Organization argues that with proper adaptive responses, no one need die due to heat. Of course, knowing what to do and doing it are two different things, meaning we must prioritize better adaptation to weather extremes.
4) Heat waves will likely become more common and more intense.
Another place the IPCC expresses its strongest confidence is in its heat-wave projections, virtually certain heat waves will become more frequent and intense. It projects these increases to occur across scenarios of the future, with greater future emissions associated with a greater increase in heat waves. That means however fast the world continues to act to reduce fossil-fuel consumption, improved adaptation will be needed regardless.
5) The world is going to need a lot more air conditioning, and that means lots more energy.
More heat means more demand for air conditioning. The International Energy Agency estimates there are about 2 billion air conditioners in the world today. That number is expected to almost triple by 2050, with most of the growth in India and China and elsewhere. In the United States, about 90% of households already have air conditioning. In India, it’s only about 5% but will likely grow quickly in coming decades. More air conditioners mean more energy consumption — the IEA estimates that 37% of the increase in electricity consumption to 2050 will be due to cooling.
That increased demand means we must put a priority on both more efficient air-conditioning technologies and deploying more carbon-free energy supply, like nuclear, wind and solar. Until we do, we should fully expect that fossil fuels will power increased air conditioning because if the choice is between being hot and being cool, we know that people around the world will choose cool, regardless of energy supply, just like we do here in the United States.
Heat waves are a fact. So, too, that they will become more common and intense. That means we need to double down on our efforts to prepare so that when heat waves do occur, their harm is limited.
Roger Pielke Jr. is a professor of environmental studies at the University of Colorado Boulder. He writes on science, policy and politics at The Honest Broker, rogerpielkejr.substack.com.