As the extreme heat now baking the U.S. and other spots around the globe is being fueled by climate change, scientists say we are likely to see similarly hot summers in the future.
But, while this type of heat is expected more often, that does not mean every summer will look like this year’s.
“We have very high scientific confidence that the world will continue to experience summers like this one and in fact that the frequency of extreme heat will intensify further in response to further global warming,” said Noah Diffenbaugh, a professor of Earth system science at Stanford University.
He noted that “the climate’s always going to vary,” but added that “we’re already in a climate where what used to be unprecedented heat conditions are now much more likely.”
This July is expected to be the hottest month the world has ever seen. So far this summer, Phoenix has seen a 26-day streak of temperatures reaching higher than 110 degrees, Miami saw temperatures of 100 degrees for 37 days with 13 days in a row higher than 106 degrees. Texas alone has seen 13 deaths linked to the heat wave, according to The Associated Press.
During climate envoy John Kerry’s recent trip to Beijing, some parts of China saw temperatures reach more than 120 degrees, while countries including Spain, Italy and Greece have also scorched.
Scientists say that climate change bears significant responsibility for the sweltering heat. According to the Intergovernmental Panel on Climate Change, every additional 0.9 degrees of global warming causes “clearly discernible increases in the intensity and frequency of hot extremes including heatwaves.”
Meanwhile, research published this week found the heat waves impacting the U.S. and southern Europe would have been “virtually impossible” without climate change, while China’s heat wave would have been a 1-in-250-year event.
The research from the World Weather Attribution initiative also said that unless the world “rapidly” stops burning fossil fuels, these events will become even more common.
Specifically, it predicted that a heat wave like the recent ones would happen every two to five years if the planet reaches 3.6 degrees of warming compared to pre-industrial levels. We’re already more than halfway there, having reached about 2 degrees of warming.
Diffenbaugh noted that this warming represents the change in the global average temperature, and said temperatures have actually risen more on land — where people actually live — than over the oceans.
“The places where people live, on land, have overall warmed more than the global average and we also have evidence…that many of the areas that are highly populated exhibit these surface atmosphere feedbacks that amplify the warming,” he said.
One way that climate change contributes to extreme heat is by increasing the baseline temperature.
“One of the most direct impacts from climate change is warming of the atmosphere and warming of the oceans and so that alone — when you have climate change leading to warmer conditions, the baseline of what is normal in terms of temperature is also elevated,” said Andrew Kruczkiewicz, a senior researcher at Columbia University’s International Research Institute for Climate and Society.
Diffenbaugh also said that because there’s more heat in the climate system, when the conditions that create a heat wave come together, “they’re more likely to produce higher temperatures, broader geographic extent of high temperatures and longer persistence of high temperatures.”
But, while climate change is a contributing factor, it is not the only reason heat waves occur.
Andy Hoell, a research meteorologist with the National Oceanic and Atmospheric Administration, said other factors include natural variations in the weather and El Niño — a phenomenon in which winds that blow west along the equator weaken, pushing warm water east toward the West Coast of the U.S.
El Niño, which typically occurs every two to seven years, can cause the northern U.S. and Canada to be dryer and warmer than usual while the Southeast becomes wetter.
“Weather systems and weather patterns sometimes they’re slower in the summer than they are in the wintertime and as a result of that, what happens is you have prolonged temperature anomalies,” Hoell said.
He added that El Niño is also “driving anomalies in the atmosphere” and is causing “some fraction of the heat waves.”
According to the World Meteorological Association, 2016 was the warmest year on record due to a “double whammy” of a powerful El Niño event and human-caused global warming.
The extreme heat gripping the world as a result of these factors is undeniable. But the reaction from U.S. politicians to both it and climate change broadly has varied, largely along political lines.
Republicans have largely ignored, or in some cases denied, the link between the heat waves and climate change. Those on the 2024 campaign trail have had little to say about the climate crisis and have embraced policies that promote more fossil fuel use.
On the other hand, Democrats have sought to address climate change, including through last year’s passage of the Inflation Reduction Act — the most significant climate legislation in the country’s history, which among other measures provided subsidies for climate-friendly energy sources.
At least some have invoked the recent heat to call for further action.
“If this planet does not get its act together — if we in Congress do not get our act together — the planet that we’re going to be leaving our children and future generations will be increasingly unhealthy and uninhabitable,” Sen. Bernie Sanders (I-Vt.) said earlier this month during a webcast that also featured Rep. Alexandria Ocasio-Cortez (D-N.Y.) and Sen. Sheldon Whitehouse (D-R.I.).