The increase is consistent with what climate scientists have warned for decades: A seemingly small change in global average temperature (so far, about 1.2 degrees Celsius of warming since pre-industrial times) can lead to big changes in extreme heat.<p>Hotter summers also make the effects of global warming harder for the public to ignore, Dr. Hansen said via email. “People notice the extremes,” he wrote.<p>Dr. Hansen’s temperature curves also flatten out over time, as they move rightward, toward higher heat. Zeke Hausfather, a climate scientist at Berkeley Earth, said this largely reflects that some parts of the world are warming faster than others.<p>Overall, Dr. Hausfather said, the data provides “a good visualization of how when we focus just on the global average, we’re missing a lot of what’s happening.”