The environmental journalist Juliet Eilperin called the ocean temperatures “beyond belief”; The Washington Post reported that they had “baffled scientists.” Contemplating the trajectory of Arctic sea ice, the atmospheric scientist Zack Labe wrote memorably about how often he finds himself answering questions about the state of the science these days by saying, “I don’t know.” And for all the uncertainty, many of those watching the changes unfold have a queasy intuition that we may be entering a new climatic regime — and perhaps inching closer to some quite concerning tipping points.
“Shocking but not really surprising,” is how NASA’s Gavin Schmidt put it. “Even the things that are unprecedented are not surprising.” That is where we are all living now, in a climate that is both shocking and unsurprising. For several decades, those anxious about global warming have lived in fear of climate prophecies. We are beginning to simply live within them, a process that looks from some vantages like a horror story and from others surprisingly normal.
There are different ways to measure the changes, some less hair-raising than others. In a report published July 25, the World Weather Attribution network examined recent heat waves in the United States, Europe and China, finding that all but the Chinese event would have been impossible without climate change. In a stable, prewarming climate, the heat wave that baked China would have happened once every 250 years; now, the network said, it should be expected every five years. The episodes in Europe and North America, once impossible, should be expected once every 10 to 15 years. I’d bet on these frequencies being underestimates. Last summer there were 100 million Americans under heat advisories, and heat across Europe was called record-breaking then, as well. (On British television, a broadcaster complained that her meteorologist guest was being too gloomy about the heat; “I want us to be happy about the weather,” she said. In the weeks that followed, several thousand Britons died in the heat.)
But the World Weather Attribution report also characterized the heat waves in another way, incorporating a critique made by Patrick Brown of the Breakthrough Institute last summer to measure the simple size of the temperature anomaly attributable to climate change, too. By this metric, the network found, warming had added just one degree Celsius to the temperatures in China, two degrees to the heat waves in North America and two and a half degrees to southern Europe’s.
The coolheaded climate scientist Zeke Hausfather tried to quickly contextualize the recent string of anomalies to show that, in fact, they were, while alarming, nevertheless within the range of expected outcomes, given the present level of global warming. Well, at least two of the three anomalies he examined — the Antarctic sea ice was still quite off the charts. (About those, one scientist told The Guardian that “something weird is going on”; another said that the abrupt changes were “very much outside our understanding of this system.”)