15 October 2018

Estimating the Human Influence on Tropical Cyclone Intensity as the Climate Changes

Science

Quantifying the human influence on individual extreme weather events is a new and rapidly developing science. Understanding the influence of climate change on tropical cyclones poses special challenges due to their intensities and scales. We present a method designed to overcome these challenges using high-resolution hindcasts of individual tropical cyclones under their actual large-scale meteorological conditions, counterfactual conditions without human influences on the climate system, and scenarios of increased climate change.

Impact

We present a hierarchy of event attribution methodologies that are designed for different purposes. The hindcast attribution method was first introduced by us in our attribution study of September 2013 floods in Colorado (Pall et al. 2017). In this book chapter, we illustrate the nuances via two studies of Typhoon Haiyan. This work forms the basis of our upcoming Nature paper examining the human influence on Katrina, Maria, Irma and 12 other storms (Patricola and Wehner 2018). It also provided the framework for our recent forecast of an anthropogenic global warming induced 50% increase in precipitation during Hurricane Florence.

Summary

It is now possible to attribute the human influence on the intensity and precipitation of individual hurricanes, if any. Attribution statements are conditional, in the sense that no statement is made about cyclogenesis.

Contact
William D. Collins
Lawrence Berkeley National Laboratory (LBNL)
Publications
Wehner, MF, C Zarzycki, and CM Patricola.  2018.  "Estimating the Human Influence on Tropical Cyclone Intensity as the Climate Changes."