As cold temperatures are once again upon us, it’s unlikely many Canadians are thinking about heat waves. But Canadians increasingly have to deal with them, and it’s virtually certain next year won’t be any different.

In 2021, a heat wave stifled parts of B.C., killing roughly 600 people. As a result, many people rushed out to buy air conditioners, and the government even created a program to provide free AC to low-income families.

The effort to stay cool in a warming world is a challenge. Our air conditioners are not only hooked up to energy grids that may be fossil fuel-intensive, but they often leak, emitting harmful greenhouse gases — the most concerning being hydrochlorofluorocarbons (HFCs) — into the atmosphere.

They also emit a lot of heat themselves.

So how do countries keep their citizens cool and safe as heat waves become more frequent and intense without increasing their carbon footprint?

The answer is called sustainable cooling.