NOAA Satellite image of Major Hurricane Dorian
Does global climate change have an influence on tropical cyclone activity and can these influences be detected? This is important given the high risk to populations along coastal regions. This question was tackled in a recent assessment published in The Bulletin of the American Meteorological Society (BAMS): Tropical Cyclones and Climate Change Assessment (1)
In this assessment, the authors focused on the question: “Can an anthropogenic influence on tropical cyclone activity be detected in past data?” The paper reviewed a number of published case studies about possible detectable anthropogenic influence on tropical cyclones and concluded that there was:
“at least a low to medium confidence that the observed poleward migration of the latitude of maximum intensity in the western North Pacific is detectable, or highly unusual compared to expected natural variability.”
The opinions on the team were divided, however, on whether any observed tropical cyclone changes could be attributed directly to anthropogenic influence and these opinions are summarized here: https://journals.ametsoc.org/view-large/12351541
Storm Surge and Extreme Rainfall
A storm surge causes tides to quickly rise while rough waves pound the concrete seawall along the shores of Lake Pontchartrain. Hurricane Isaac made landfall along the Gulf Coast and now threatens New Orleans.
Regarding storm surge, the paper indicating that:
“a widespread worsening of total inundation levels during storms is occurring because of the global mean sea level rise associated with anthropogenic warming, assuming all other factors equal, although we note that no TC climate change signal has been convincingly detected in sea level extremes data. To date, there is not convincing evidence of a detectable anthropogenic influence on hurricane precipitation rates, in contrast to the case for extreme precipitation in general, where some anthropogenic influence has been detected.”
Reference
- Knutson, T., and Coauthors, 2019: Tropical Cyclones and Climate Change Assessment: Part I: Detection and Attribution. Bull. Amer. Meteor. Soc., 100, 1987–2007, https://doi.org/10.1175/BAMS-D-18-0189.1.
