【気候変動】温暖化で今のところは快適な米国の気象条件

The weather experienced by the majority of the population of the United States has become more pleasant over the past 40 years, owing to climate change, reports a paper published this week in Nature. However, the study estimates that, by the end of the century, 88% of the US public will be experiencing less pleasant weather, as a result of increasingly warmer summers.

Previously published population growth models have shown that Americans prefer to live where winters are warm, and dislike hot, humid summers. Patrick Egan and Megan Mullin combine this research with other research on the effects of weather on local population growth to develop an index of people’s weather preferences. They find that, in the continental US states (excluding Alaska), 80% of the population lives in counties that are experiencing more pleasant weather than they did in 1970, with almost all Americans now experiencing the milder winters that they typically prefer and negligible temperature and humidity increases in summer. However, the authors suggest that this trend is unlikely to continue. They find that, if greenhouse gas emissions continue unabated at their current rate, 88% of the US public will experience weather in 2100 that is less preferable than current weather.

They conclude that the weather patterns of recent decades may have served as a poor source of motivation for Americans to demand a policy response to climate change, but that public concern could rise once people’s everyday experience of climate change becomes less pleasant.