Dr. James Hansen has been called the “father of climate change awareness.” In 1988, Hansen first warned about the dangers of global warming when he testified before Congress. At the time, he was the top climate scientist at NASA, where he headed the Goddard Institute for Space Studies. We speak with world-renowned climatologist Dr. James Hansen on what role climate change played in unleashing Hurricane Harvey.
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JAMES HANSEN: Yeah, in fact, there are—there are very clear links. Let me mention three of them. One of them is sea level. Sea level was stable for the last several thousand years. But with the beginning of changes in atmospheric composition, caused by burning fossil fuels mainly, the planet is getting warmer, and sea level has begun to go up, because the ocean is getting warmer and because ice is melting. Well, on the global average, it’s gone up by about 20 centimeters, which is about eight inches; however, it’s not the same every place. Along the East Coast of the United States and the Gulf Coast, it’s larger than the global average. It’s a good foot. So that’s a significant contribution to the magnitude of the storm surges that drive the water onto Houston and the other regions. So that’s one thing.
Another is, the amount of water vapor in the atmosphere is increasing because the atmosphere is getting warmer, and therefore the amount of water being dumped during these storms is larger because of the human, global-made—global warming, human-made global warming, which is now more than 1 degree Celsius. And the simple equations for how much water vapor is in the atmosphere as a function of temperature would be several percent, but, in addition, the distribution of the storms that release the moisture is changing. We’re getting more of the rainfall in extreme large events. So, that’s a significant factor.
And then, the third thing is the strength of storms. Thunderstorms, tornadoes, tropical storms all get their energy from the latent energy of water vapor. And because the atmosphere now holds more water vapor, the strength of those storms can be greater. And so, there are substantial human-made effects on these storms. It’s not debatable now. These are all well-established facts.