One to 2 degrees Celsius of warming can do a lot of damage.
Climate scientists have long warned that global warming would lead to extreme heat in many parts of the world. But the 120 degree Fahrenheit temperatures brought on by the heatwave in the Pacific Northwest in June were more in line with what researchers had imagined would occur later this century. “Astonished” is the word Michael Wehner, an extreme weather researcher at Lawrence Berkeley National Laboratory, used to describe his reaction to the heat in an interview with National Geographic. He was one of two dozen extreme weather and climate researchers who conducted an analysis in the days following the heatwave that found it would not have occurred in the absence of anthropogenic climate change.
“We said it is virtually impossible without climate change,” Wehner said of the event. “But I would have said beforehand it is virtually impossible with climate change.”
As more seemingly impossible events followed — intense flooding in Germany and Belgium killed more than 200 and counting, a massive wildfire in Oregon grew by 1,000 acres per hour, and a year’s worth of rain fell on central China in just three days — news outlets began reporting on researchers’ unease. “This catastrophic summer even has climate scientists worried,” a headline in the National Observer read. “Climate scientists shocked by scale of floods in Germany,” the Guardian wrote. CNN: “Scientists are worried by how fast the climate crisis has amplified extreme weather.”
What are we to make of this? Has climate change entered warp speed?
Not exactly, says Daniel Swain, a climate scientist at the University of California, Los Angeles who is an authority on extreme weather, wildfires, and other climate impacts.
“I’m less convinced that recent events tell us that things are moving faster than projections have suggested,” Swain said. “But I am increasingly convinced that we’ve underestimated the impacts of some of the changes that were actually fairly well predicted.”
Grist caught up with Swain to talk about extreme weather, climate models, and how even subtle increases in temperature can bring about immense change.