Climate change can be expected to boost the number of annual premature U.S. deaths from heat waves in coming decades and to increase mental health problems from extreme weather like hurricanes and floods, a U.S. study said Monday.

"I don't know that we've seen something like this before, where we have a force that has such a multitude of effects," Surgeon General Vivek Murthy told reporters at the White House about the study. "There's not one single source that we can target with climate change, there are multiple paths that we have to address."

Heat waves were estimated to cause 670 to 1,300 U.S. deaths annually in recent years. Premature U.S. deaths from heat waves can be expected to rise more than 27,000 per year by 2100, from a 1990 baseline, one scenario in the study said. The rise outpaced projected decreases in deaths from extreme cold.