What extreme heat waves tell us about the dangers of climate change

Scientists have simply had too little time with a climate system warmed by human activity to determine the answers to such questions.

“There is a lot of uncertainty when it comes to these unprecedented and record-breaking events,” Flavio Lehner, assistant professor of Earth and Atmospheric Sciences at Cornell, said in an email. “You can’t say with the utmost confidence that the models are getting this or not getting this,” when it comes to certain extreme events.

What other forces can contribute to very hot heat waves?

Several researchers are investigating the extent to which certain forces can exacerbate heat waves and whether they are accurately portrayed in today’s models, Lehner says.

These include possible feedback effects, such as dehydration of soil and plants in some regions. Above certain thresholds, this can accelerate warming during heat waves because energy that would otherwise go into evaporating water is used to heat the air.

Another open scientific question is whether climate change itself increases the persistence of certain atmospheric patterns that clearly fuel heat waves. That includes building up high-pressure ridges that push warm air down, creating so-called heat domes that float and bake over large areas.

Both forces may have played a major role in fueling the heat wave in the Pacific Northwest last year, according to an upcoming paper. In Europe, researchers have noted that a split in the jet stream and warming ocean waters may play a role in the increase in extreme heat across the continent.

Why didn’t the scientists warn us properly?

Ugh. Some publications have even printed words to this effect, in response to increasingly extreme weather conditions.

But to be clear, scientists have been sounding the alarm for decades, in every way possible, that climate change will make the planet warmer, stranger, harder to predict and in many ways more dangerous to people, animals and ecosystems. And they’ve been candid about the limits of their understanding. The main charge they have faced until recently (and still are, in many quarters) is that they are terrifying doomsayers who exaggerate the threat to research funding or political reasons.

Real-world events that highlight flaws in climate models, to the extent they have, don’t amount to some “aha, gotcha, scientists were always wrong” kind of revelation. They provide a stress test of the tools, one that researchers eagerly use to refine their understanding of these systems and the models they’ve created to represent them, Lehner says.

Chris Field, director of the Stanford Woods Institute for the Environment, put it bluntly in a letter responding to the New York Times claim that “few thought [climate change] would arrive so soon”: “The problem has not been that the scientists were wrong. Despite clear warnings consistent with the available evidence, scientists committed to informing the public have struggled to make their voices heard in an atmosphere filled with false accusations of alarmism and political motivation.