Superstorm Sandy’s Link To Climate Change: ‘The Case Has Strengthened’ Says Jennifer Francis

by Joe Romm, Climate Progress, October 28, 2013

Sandy slams Atlantic City October 29, 2012. If we don’t slash carbon pollution, then by mid-century, we could see such a storm surge every year.

One year ago, Superstorm Sandy made landfall in New York and New Jersey. It killed more than 100 people, displaced thousands, and inflicted an estimated $65 billion in damages.

We’ve written extensively about how global warming worsened the impact of Superstorm Sandy.

In particular, a recent study by NOAA researchers found, “climate-change related increases in sea level have nearly doubled today’s annual probability of a Sandy-level flood recurrence as compared to 1950.” On our current CO2 emissions path, the Jersey shore from Atlantic City to Cape May could see Sandy-level storm surges yearly by mid-century!

Dr. Jennifer Francis of Rutgers University’s Institute of Marine and Coastal Sciences is one of the world’s leading experts on the connection between climate change and extreme weather (see here and here). She has also written about the many ways global warming made Sandy so unusually destructive.

I asked Dr. Francis for her latest thoughts on the link between human-caused climate change and the superstorm. She replied:

I think the case has strengthened. I’ve done a bit more research into the linkage with the very warm Arctic following the record 2012 ice loss, and it appears that the heat released from the Arctic Ocean in the fall created a substantial positive anomaly in the upper-level atmospheric heights in the North Atlantic. This likely contributed to the strong ridge and blocking high that existed when Sandy came along, and that ultimately not only steered Sandy westward but also set up the strong pressure gradient between Sandy and the blocking high that caused the enormous expanse of tropical-storm-force winds from Delaware to Nova Scotia.

In addition to the Arctic connection, the abnormally high sea-surface temperatures all along the eastern seaboard at the time, which must have some component associated with globally warming oceans, likely helped Sandy maintain tropical characteristics longer and allowed the storm to travel farther northward than would be expected in late October. Warmer ocean waters would also increase evaporation rates, adding to the moisture and latent heat available to the storm.

Atmospheric conditions during Sandy’s transit along the eastern seaboard, including the invasion of cold Arctic air into the middle latitudes of North America and the high-pressure blocking pattern in the northwest Atlantic.

Figures (above and below) from Francis’s March 2013 paper with Charles H. Greene, director of Cornell’s Ocean Resources and Ecosystems program, are illustrative.

After the convergence of tropical and extra-tropical storm systems, the hybrid Superstorm Sandy made landfall, bringing strong winds, storm surge, and flooding to areas near the coast and blizzard conditions to Appalachia.

BOTTOM LINE: Manmade climate change significantly worsened the chances a unique superstorm like Sandy would devastate New Jersey and New York. If humanity’s unrestricted emissions of carbon pollution continue unabated, however, Sandy-type storm surges will become the norm on the East Coast.

http://thinkprogress.org/climate/2013/10/28/2843871/superstorm-sandy-climate-change/