Connecting Weather Events to Climate Change

Oct 3, 2017

The complicated clean up from Hurricanes Maria and Harvey continues. Millions are without power or fresh water, especially in the US commonwealth of Puerto Rico and in the United States Virgin Islands.

One of the assertions we often hear in recent years when a powerful hurricane strikes is that while climate change likely impacts the frequency and severity of major storms, we can’t connect any particular storm to the phenomenon of global warming. George Stone is a former natural sciences instructor at Milwaukee Area Technical College and he says that assertion is wrong. 

"People say, 'Oh you can't connect any individual weather event with the climate.' Of course you can, because climate is the context in which the weather events develop," says Stone. 

He uses the recent hurricanes as an example of weather events being impacted by changes in global climate. "The ocean surface temperatures are higher than they would have been normally because of global warming... Last year we saw a couple of record breaking, torrential rainstorms along the Gulf Coast - first in the Houston area and then later on in Louisiana. And then the hurricane that went up the East Coast had record breaking amounts of rainfall in North Carolina, basically flooded out the whole state." 

He continues, "Well where does all that water come from? Why is it record breaking? Because there's more water vapor in the air than there used to be - approximately 6% more water vapor in the atmosphere than there was about 40 years ago. Well that's huge, because it's the water vapor that condenses to form the rain - more water vapor, more rain - it's also the condensation of the water vapor that provides the latent heat, the energy source for the storms."  

Further, Stone contends that to simply label major hurricanes like Maria or Harvey as "natural disasters" only tells part of the story.  "To be accurate," he concludes, "we should call them 'natural disasters exacerbated by human influence'."

While Wisconsin does not experience hurricanes the way coastal areas do, one environmental group says the state is at significant risk from the effects of climate change-enhanced severe weather.  Marion Kinosian is a conservation fellow with Wisconsin Environment.  A recent report by the organization says current federal budget proposals could spell harm.

"Really, the bottom line is we need to make our communities less susceptible to flooding, sewage overflows and leaks from toxic waste sites," she says.  Kinosian says it's up to Wisconsin's U.S. senators to protect the state in the face of that peril.