Data released yesterday shows that the last 12 months were the hottest ever recorded in the United States. In Texas, the droughts were so bad that some towns ran out of water. Wildfires burned millions of acres of dried-out land. In the Northeast, winter never really came. February felt like spring.
Some of this warm weather can be traced to a weather pattern called La Niña. And most climate scientists are still reluctant to blame climate change for causing any particular weather event. But consider the context: This is the 326th month in a row that temperatures across the nation have been above average. The last time a month's temperatures fell below global averages was February 1985.
Averages are tricky, of course. They don’t reflect our day-to-day experiences of basking in the sun, shivering in the wind, or staring at the window at freak snow storms. And these experiences—our decisions about how many layers to wear and whether to bike or take the bus to work—have a strong influence on our beliefs about climate change. It probably won’t be quite as warm over the next 12 months as it was in the last 12, although the temperatures from January through April are the highest on record again. And if the coming summer happens to be mild, if snow falls in massive quantities next winter, some of the people who are starting to worry about climate change will breath a sigh of relief and stop worrying quite so much.
But variation from day to day or even year to year masks the longer trend: the planet is steadily getting warmer. Climate scientist James Hansen, who began calling attention to the dangers of climate change before anyone even knew to think about it, is confident that there’s a connection between some of the heat waves we’re seeing now and global climate change. As he and a couple of colleagues wrote in a recent paper, “There is no need to equivocate about the summer heat waves in Texas in 2011 and Moscow in 2010... it is nearly certain that they would not have occurred in the absence of global warming.” And that means that hottest year ever won't be the hottest ever for very long.