With cooler temps arriving, America’s long, hottest summer of 2023 is now one for the record books. It was a season of baffling heat, particularly across the South and Southwest: For nearly all of July and August, for example, the daily high temperatures were above 96 degrees in Baton Rouge, Louisiana — and New Orleans hit a record high of 105 degrees

Although most of the nation roasted in extremely hot temps, Louisiana was the only state to officially have its hottest summer ever. The extreme heat was particularly bad across the rest of the Gulf Coast, too, from Texas to Florida. The summer not only smashed heat records but left many people dead. 

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While things are milder now, they are by no means back to normal globally: with spring heatwaves scorching the Southern Hemisphere and temperatures still above average in much of the U.S., we’re still breaking heat records. On Friday and Saturday, the world, on the whole, set a very ominous benchmark: on those two days, the global average temperature was 2 degrees Celsius higher than the pre-industrial average. 

That is to say, we briefly surpassed the threshold beyond which lies catastrophic climate change, the barrier that we need to not cross if we want to maintain anything resembling the global ecosystem as it has existed during our lifetimes, and the many, many comforts that come with it.

“Our best estimate is that this was the first day when global temperature was more than 2°C above 1850-1900 (or pre-industrial) levels, at 2.06°C,” Samantha Burgess, the deputy director of the Copernicus Climate Change Service, tweeted on Sunday.

Dangerously high highs often affect places that are and have historically been Black communities.

There are a number of caveats to this record, one being that it’s an early estimate that could be revised (calculating the average of temperatures from all around the globe is complicated), and another being that the 2 degrees Celsius threshold discussed in international climate talks and environment-related policy is a global average over the course of decades, not one weekend. It doesn’t mean that we’ve failed, but it’s a big, bad first nonetheless. 

Richard Allan, a climate scientist at the University of Reading, told CNN that it amounted to a “canary in the coal mine,” adding that it “underscores the urgency of tackling greenhouse gas emissions.”

Crossing 2 degrees Celsius in a sustained manner would add an additional month (compared to mid-century averages) of dangerous summer temperatures for more than a quarter of the world’s population, according to a NASA study.

And as this summer’s seemingly endless heatwaves foreshadowed, those dangerously high highs often affect places that are and have historically been Black communities, like New Orleans and Baton Rouge. Even in cities that aren’t predominantly Black, the effects of redlining Black neighborhoods nearly a century ago have resulted in those areas being markedly hotter today than whiter parts of the same cities.

With yet another major El Niño weather pattern established in the Pacific (which helped dive this past summer’s high temperatures), don’t expect the record highs to go away anytime soon, even if the global averages drop back below the 2 degrees Celsius threshold. 

In Rio de Janeiro, the temperature hit 108 degrees, with the heat index hitting nearly 140. The death of a fan at a Taylor Swift concert due to heat-related issues has received the most international media attention, but the country has its own climate justice issues when it comes to extreme heat: the favelas in Rio tend to be hotter than the rest of the city, due partly to their ad-hoc construction and their locations too. And the people who live in the favelas are not only very poor, but some 67% are Black, too.

Willy Blackmore is a freelance writer and editor covering food, culture, and the environment. He lives in Brooklyn.