Last month, as a record heat wave roasted California, statewide energy consumption skyrocketed, forcing grid operators to issue rolling blackouts for the first time in nearly 20 years. The reason the grid was under so much strain? Millions upon millions of air conditioners were running full tilt. It was a stark illustration of the challenge humanity will face trying to keep everybody cool as the planet overheats.

That challenge cuts both ways: Climate change  is driving up demand for air conditioning, refrigeration, and other technologies that keep us and our food cool. Yet, cooling makes a sizable contribution to the climate crisis.

In 2018, cooling equipment accounted for 17 percent of global electricity demand, according to a recent U.N. report. Most of the electricity powering those devices was produced by burning fossil fuels, which drives global warming. To make matters worse, most of today’s refrigerators and ACs use a class of coolants called hydrofluorocarbons, or HFCs, greenhouse gases thousands of times more powerful than carbon dioxide.