There is nothing surprising about a hurricane hitting the central Texas coast in late August, as Hurricane Harvey did on Friday night. Hurricanes have been recorded since Christopher Columbus encountered one in 1495. We know they occur with some regularity in the Atlantic at this time of year.
But Harvey soon became an inordinately severe tropical storm, as it pulled water from the atmosphere down to Earth with extraordinary efficiency and intensity, and it stuck around. Since Friday, it has dumped an estimated
21 trillion gallons on the Texas coast, fulfilling all meteorological predictions that it would be “unprecedented” and “catastrophic.”
The National Weather Service
reported Tuesday that a preliminary measurement from Cedar Bayou, Texas, recorded 51.88 inches of rain, breaking the rainfall record for a single tropical storm or hurricane in the continental United States. (The last record of 48 inches was set during tropical cyclone Amelia in Texas in 1978.) On Wednesday morning, the agency reported the coast was still under merciless wet assault, with “catastrophic and life-threatening flooding [continuing] in southeastern Texas and portions of southwestern Louisiana.”
Climate scientists have
confirmed that climate change made Harvey a worse storm. Because of long-term warming trends, the ocean is warmer, creating more energy for a hurricane to tap. The atmosphere is warmer too, sending more water vapor into the air that can then be pulled back down by a hurricane as rain.
Adam Sobel, an atmospheric scientist who directs Columbia University’s Initiative on Extreme Weather and Climate, estimates that 5 to 10 percent of the rainfall was due to global warming (more conservative than the
30 percent estimate from Kevin Trenberth, a senior scientist at the US National Center for Atmospheric Research).