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The temperature in Washington has topped 90 degrees for 12 straight days. While I was sitting inside during one of those days trying to avoid the heat, I spent some time making a chart. You can see it above.
It shows the average number of days per year when the temperature cracked 90 degrees in various cities, during the first eight decades of the 20th century (before global warming became more severe), and then in the past 10 years.
I chose 15 major cities from the National Weather Service’s database, without knowing exactly what I’d find. In four of the cities, mostly in the Midwest, the numbers are virtually unchanged. But in the other 11, there has been a substantial increase. Houston, for example, used to have 89 days above 90 degrees in a typical year; it now has 115. Atlanta has gone from 36 to 56, and Denver from 27 to 48.
By this measure, the Boston of today feels like the New York of the 20th century. Washington is on its way to resembling the Memphis of old. And Miami is more like Dallas used to be. (To see a larger version of the chart, click here.)
And the planet is only going to keep getting hotter until our political leaders — that is, Republican leaders, who are the obstacle to action on climate change — do something about it.
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Daily highs — the data I’ve used here — may understate global warming. Nationwide, The Washington Post’s Andrew Freedman writes, “summer low temperatures have been increasing far faster than daytime highs.”
More than half of the United States endured a heat wave in recent days. India and Greenland have also experienced higher-than-normal temperatures this month. And in parts of Poland, France, Germany and the Czech Republic, temperature records were broken last month, according to Vox’s Umair Irfan.
Scientists expect this month to be the hottest July ever recorded, and last month was the hottest June on record, notes Time magazine’s Jasmine Aguilera.
Jacob Fenston, writing for the Washington radio station WAMU, looks ahead: “Historically, D.C. experienced a week’s worth of days where it felt like 100 degrees. By 2050, there could be almost six weeks (41 days) where the heat index rises to 100 degrees,” he writes. “By the end of the century, D.C. could be sweating through a solid two months and one week of days that feel like 100 degrees. This is all if the world takes no serious action to reduce greenhouse gas emissions.”
Fifty years after the moon landing, Lori Garver, the former deputy NASA administrator, argues that the space agency should refocus its efforts on a more terrestrial threat: a warming world. “Climate change — not Russia, much less China — is today’s existential threat,” she writes in The Washington Post.
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