Events like Hurricane Harvey and Hurricane Irma naturally raise questions about possible connections between extreme weather and human-caused climate change. Although this is sometimes obscured in media coverage, science has identified solid connections between powerful hurricanes and climate change. Failing to act on this understanding unnecessarily increases the risk from future events:
1. Theory, models, and observations all indicate that extreme precipitation increases in a warmer climate. This is highly relevant to Harvey, from which the main source of damage was extreme precipitation.
2. Theory and models agree that climate change increases the likelihood of very intense storms. Harvey was a category 4 storm when it first made landfall and Irma, a Category 5 hurricane, is one of the most powerful storms ever recorded in the Atlantic Ocean.
3. Damage from storm surge is heightened not only by higher wind speeds, but because sea level is higher to begin with as a result of climate change.
More speculative is a possible connection between rapid warming in the Arctic and weak “steering winds,” which is what caused Harvey to linger so long and dump so much rain over the Houston area.
What this adds up to is that climate change is increasing the number of very intense hurricanes, and tends to make all hurricanes more damaging when they do occur.
What should we be doing? First, prepare for elevated risk from extreme weather events (including hurricanes). Failure to do this subjects us to more potential harm than is necessary. It would have been good, for example, for Trump to have let stand Obama’s Federal Flood Risk Management Standard, which sought to protect infrastructure from flooding. Second, we should maintain strong budgetary support for scientific observation and modeling programs, including those needed to understand and predict extreme weather events and how they are affected by climate change. The understanding gained from this work will save lives and property. Finally, of course, this tragedy reminds us (once again) that we need to take immediate and effective action to prevent future climate change by reducing emissions of greenhouse gases to the atmosphere.
– WHRC President Philip B. Duffy
– Senior Advisor to the President John P. Holdren