America Had A Wet, Hot 2018

America Had A Wet, Hot 2018

On Tuesday, NOAA and NASA released their much-anticipated analyses of global climate trends for 2018. As we expected, the agencies confirmed it was the fourth-warmest year on record for planet Earth. But the reports also highlighted just how striking a year it was for the U.S. specifically, with most of the country feeling the heat and various regions experiencing either extreme rainfall or drought.

Across the world, global temperatures were 1.42- 1.5 degrees Fahrenheit warmer than the long-term average, placing 2018 behind 2016, 2017, and 2015 as the fourth warmest on record. The U.S.-specific numbers closely mirror the planetary heat wave: Overall, temperatures were about 1.5 degrees higher than the 20th-century average according to NOAA, making it America’s 14th-warmest year.

With the exception of the northern Great Plains, which had a relatively average year, most regions of the country — particularly the West, Southwest, and Southeast — were warm.

Pockets of the Mid-Atlantic and Southwest saw their warmest year on record when it came to overnight low temperatures, and most of the country saw overnight low temperatures that far exceeded the 20th-century average. Nights, in other words, are getting uncomfortably sweaty for many Americans.

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“This is one of the most significant and emergent themes in the 21st century,” Deke Arndt, chief of the climate monitoring branch for NOAA’s National Centres for Environmental Information, told reporters on a press call, adding that considering just morning-time low temperatures, the U.S. had its 7th-warmest year on record. This, Arndt explained, is what we’d expect in a warming world, where the shrinking of the so-called atmospheric boundary layer at night amplifies warming.

Heat aside, there were also some notable patterns when it came to rainfall or a lack thereof. It was the third-wettest year on record for the country, but the rain didn’t fall evenly. In fact, it was concentrated like a bullseye over the Mid-Atlantic, with nine states along the Appalachians—from Tennessee to Massachusetts — experiencing their wettest year on record, according to Arndt.

Image: NASA

The southwestern U.S. around Four Corners, meanwhile, was desperately thirsty. Most of Utah and Arizona, along with large portions of Colorado and New Mexico, experienced drought conditions all year, continuing what Ardnt described as an “entrenched and very intense” dry spell that began ramping up in the late 1990s.

The fingerprints of climate change can be seen across this wet-dry seesaw. On the wetter side, a warmer atmosphere can hold and dump more water vapour, and climate scientists predict an uptick in rainfall intensity and total rainfall the Northeastern U.S. as a result. Ardnt called 2018 “an exclamation point on a trend we’re seeing toward more big rain, particularly in the Eastern U.S.”

The link between the drought out West and our warming world is a bit more subtle: As Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, explained on the press call, current precipitation levels aren’t that unusual when considering the last few thousand years of history. But the drying of the soil — which impacts not only our crops, but how prone landscapes are to catching fire—is the result of both reduced precipitation and warmer temperatures, the latter of which “is attributable to increased greenhouse gases,” Schmidt said.

The bottom line? Climate change is real, and its effects are coming home to roost. The most sobering statistic from the new report makes that clear: Americans lost $127 billion to weather and climate disasters last year, the fourth-largest total since 1980. While the agencies didn’t quantify how much of those losses was attributable directly to a climate change versus where and how we choose to live, there’s ample evidence some of these disasters are being amplified in a warming world.

The report comes on the heels of a State of the Union address in which President Trump touted American oil and natural gas production, while failing to mention climate change.