From multiple heat waves and raging wildfires in the western United States and Canada, to deadly flooding in Germany, Belgium and China, a string of extreme weather events across the globe this summer have driven home the pressing threat of climate change.

What is the link between such extreme incidents and the human-caused global warming that scientists have been warning about for decades, and what action needs to be taken? In for Jim Braude, Sue O’Connell was joined on Greater Boston by Susan Joy Hassol, director of the nonprofit Climate Communication; and David Cash, dean of UMass Boston’s Graduate School of Policy & Global Studies, who called on policymakers to consider vulnerable populations who will be most impacted by climate change.

On average, 12,000 Americans die each year from extreme heat, and Hassol says climate change will keep impacting places in the U.S. that are not prepared for higher temperatures. “People in areas of the South are more acclimated to extreme heat. They have air conditioning, they’re physiologically more acclimated,” she said. “And so it doesn’t affect them as much. What happens as the world gets warmer though is you get these heatwaves in places like the Pacific Northwest, where very few people have air conditioning or in Canada, where very few people do.”

“It [heat] is the most deadly form of extreme weather we have in the U.S. and if we continue on a path of increasing emissions, that number will go up to maybe 100,000 Americans,” she added.

WATCH: A summer of extreme weather shows climate change’s impact