Adults doubted us. We found a way to shrink emissions at our middle school anyway

• Read more from My DIY climate hack, a new series on everyday people's creative solutions to the climate crisis

When temperatures creep past 90F in Oakland, California, the mini air-conditioning units in the classrooms at Melrose Leadership Academy can't keep pace. So the middle schoolers in MLA's chapter of the climate justice group Youth vs Apocalypse started doing some extra homework: they researched, planned and proposed installing a heat pump on campus.

Heating buildings accounts for 10% of CO₂ emissions globally, according to the International Energy Agency. Heat pumps have become an increasingly popular clean-energy technology because they can both heat and cool using electricity, reducing greenhouse gas emissions.