The study, published Tuesday in Nature Mental Health, randomly surveyed more than 2,400 Canadians aged 13 or older and categorized them using a climate change anxiety scale developed in the U.S. It asks the extent to which people agree with statements such as "Thinking about climate change makes it difficult for me to sleep" or "I find myself crying because of climate change."

It found that 90 per cent of respondents were concerned about climate change and 68 per cent felt some level of anxiety — something the researchers thought was a normal, healthy response, given the impacts of climate change such as wildfires and extreme heat.

But 2.35 per cent had "clinically relevant" symptoms.