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Harvey's extreme rainfall due to climate change

Woman and family look out at floodwaters in Houston, Texas.
Woman and family look out at floodwaters caused by Harvey in Houston, TX. Photo: Charlie Riedel / AP

Rainfall from Hurricane Harvey, which struck Houston over the summer, was at least 15% heavier due to human caused climate change, according to two independent studies by researchers at the Lawrence Berkeley National Laboratory and Royal Netherlands Meteorological Institute. Hurricanes like Harvey are also three times more likely today than in 1900, researchers reported.

Why it matters: This isn't the first time scientists have attributed violent weather events to a warming planet, The Washington Post reports. Scientists have also warned of the increased likelihood of droughts such as the one in Texas in 2010 and floods similar to Colorado's in 2013. These findings suggest cities and communities may need to reassess their risk and find new ways to prepare for harsher weather as climate change continues.

The studies:

  1. Researchers in the Netherlands found the storm's precipitation was 15% more intense due to climate change compared to a similar storm in the early 1900s. They also reported "a deluge such as Harvey would have occurred in the region once every 2,400 years in the pre-warming period but that it is now a 1-in-800 year event — and is becoming more likely," per The Post.
  2. The Lawrence Berkeley National Laboratory team found that rainfall was increased by at least 19% and as much as 38%, and that the chances of a storm with as much rainfall has at least tripled since the 1900s.
“We have two independent efforts with essentially the same answer. There’s a clear human fingerprint. The numbers will undoubtedly change as more researchers look at this with different techniques, and perhaps different data sets and different methods. But our numbers are kind of big.”— Michael Wehner, senior staff scientist at Berkeley

How it works: "Climate change, caused by increasing greenhouse gases in the atmosphere from the burning of fossil fuels, is raising temperatures globally. Warmer air can carry more moisture, which can lead to more extreme rainfall events, and warmer ocean surface temperatures are known to intensify the most powerful hurricanes," according to the press release from the American Geophysical Union fall meeting taking place this week.