Flood Risk Intelligence
May 19, 2021

New Paper: Attributable human-induced changes in the magnitude of flooding during Hurricane Harvey

This research estimates $13bn of damages caused were attributable to anthropogenic global warming.

In August 2017 Hurricane Harvey, a category 4 cyclone, made landfall across the Greater Houston area. Its estimated cost ranges between 85 - 125 billion USD, the 2nd most expensive tropical cyclone in US history after adjustment for inflation. 

In this paper Wehner and Sampson investigate the degree to which human induced climate change altered the flooding experienced during Hurricane Harvey, relative to if the climate had been in a ‘natural state’.

Simulation of the actual and counterfactual flood in the South Houston and Pasadena neighbourhoods. a The actual flood that was. b The counterfactual flood that might have been in the absence of climate change if human activities increased Harvey storm total precipitation by 7%. c Same as b except precipitation increased by 38%. d Attributable flooding if human activities increased Harvey storm total precipitation by 7%. e Same as d except precipitation increased by 38%. Rainbow scale is for panels a, b, and c. Blue scale is for panels d and e. Units: meters. 999 denotes areas of permanent water.


Using Fathom’s US flood model, they find non-linearities in the relation between precipitation increase due to climate change and the resultant flood inundation. In particular, increased flood volumes due to climate change in the most heavily flooded parts of Houston during Harvey were larger than the relative increase in precipitation.

Their research concludes that climate change increased the cost of Hurricane Harvey by 14% due to rising temperatures. This roughly translates to an estimated economic loss of $13 billion, attributable to anthropogenic global warming.

The paper, which has been published in Climatic Change, can be accessed for free here.

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