As extreme heat hits many parts of the world amid a warming climate, millions of people are turning to air conditioners for relief . Research shows that household air conditioning is one of the "most effective adaptation strategies to reduce heat-related mortality and morbidity," says a Statistics Canada report released this week . That's particularly the case for older adults and vulnerable populations such as those with mental illness. But researchers who study climate adaptation say it can also be an unsustainable and problematic solution to extreme heat. Anabela Bonada, manager and research associate at the Intact Centre on Climate...