The human contribution can be up to 30 percent or so of the total rainfall coming out of the storm,� he said. It may have been a strong storm, and it may have caused a lot of problems anyway” but [human-caused climate change] amplifies the damage considerably.�

More generally, its still unclear what effect climate change is having on hurricane formation across the greater Atlantic Ocean. A draft version of a major U.S. government review of climate science due out later this year says there is medium confidence that human activities have contributed to the observed upward trend in North Atlantic hurricane activity since the 1970s. My opinion stated by the article (and supported) was that some of Hurricane Harvey was caused by human contribution.�

 Scientists, who specialize in thinking about the Earth system, are often reticent to link any one weather event to global climate change. But they say that aspects of the case of Hurricane Harvey and the recent history of tropical storms worldwide suggest global warming is making a bad situation, worse.

Climate scientists, who specialize in thinking about the Earth system as a whole, are often reticent to link any one weather event to global climate change. But they say that aspects of the case of Hurricane Harvey—and the recent history of tropical cyclones worldwide—suggest global warming is making a bad situation worse.

It may not be obvious why global warming has anything to do with hurricane strength. Climate change is caused by the release of greenhouse gases like carbon dioxide and methane into the atmosphere. These gases prevent some of the sun’s rays from bouncing back into space, trapping heat in the planetary system and raising air temperatures all over the world.