Renewable Revolution

Radio Ecoshock

June 20, 2018


My second discussion is with Jim Kossin who just published a paper in Nature about slower moving cyclones since 1950. They are slowing (think Hurricane Harvey) and the peak is moving toward the Poles. Closer to the tropics a slight there may be a slight reprieve in the odds of extreme rainfall events; further north – welcome to a new and terrible experience!


From Texas to Taiwan slow-moving hurricanes have caused record damage. Has something changed in the way these big storms work? Four well-known climate scientists are asking “Does global warming make tropical cyclones stronger?”

Dr. Jim Kossin is an Atmospheric Research Scientist. He’s with the National Oceanic and Atmospheric Administration or NOAA. Jim is currently a Lead Author on the U.S. Global Change Research Program, for their Fourth National Climate Assessment [NCA4]. He’s also working on the Intergovernmental Panel on Climate Change [IPCC] Sixth Assessment Report [AR6]. Jim has won awards and the key science he publishes is used by world climate researchers and meteorologists. He’s just published an important paper in the journal Nature.

Dr. Jim Kossin of NOAA leads climate reports for the U.S. Government and the IPCC. His specialty is big storms. Kossin’s latest paper says tropical cyclones (hurricanes) are slowing down and leaving a greater trail of destruction.

Kossin also helped co-ordinate the Special Report on Managing the Risks of Extreme Events and Disasters. He is a recognized world experts on big storms. Jim’s latest paper was published June 6th, 2018 in Nature. It is titled “A global slowdown of tropical-cyclone translation speed“.

Before we can talk about the most damaging storms in the world, we need to quickly clear up two terms. First, hurricanes and tropical cyclones are the same thing.

Second, storm scientists talk about “translation speed”. While newscasters report on the spinning speed within the hurricane (winds of 160 miles per hour, for example) – the translation speed is the progress of the storm over land or sea. If it is moving “forward” at 30 miles or kilometers per hour, that is the translation speed. This new paper is largely about a slowdown not in the winds of hurricanes (in general those are tending to increase) but in the movement of the big storms across the landscape.

That matters a lot. Hurricane Harvey stayed over Houston for a couple of days, dumping massive amounts of rain, and then doubled back for a second hit. It’s translation speed was quite low. In 2011, I covered Hurricane Irene which wasn’t all that strong by the time it hit New England. But it dumped incredible amounts of rain for several days, causing wide-spread flooding and damage. When we consider a warmer atmosphere puts more water into the sky, a slower translation speed means even more flooding.

Similarly, while scientists suspect that a slow-down in the movement of tropical cyclones/hurricanes is due to climate change, the exact mechanism has not yet been proven.

Another recent paper, published April 6th and led by Ethand Gutmann from The National Center for Atmospheric Research also suggested slower moving storms with faster winds. That study was published by the American Meteorological Society, and it backs up what our guest Jim Kossin found.

From Kossin’s paper, here are the regions most impacted by this tropical cyclone slowdown. “Of particular importance is the slowdown of 30 per cent and 20 per cent over land areas affected by western North Pacific and North Atlantic tropical cyclones, respectively, and the slowdown of 19 per cent over land areas in the Australian region.”


Jim Kossin, Kerry Emanuel, Stefan Rahmstorf and Michael Mann published a post in the RealClimate blog titled “Does global warming make tropical cyclones stronger?“.

This is your news before it’s news, on Radio Ecoshock.

My 31 minute interview with Jim Kossin

https://www.ecoshock.org/2018/06/carbon-climate-showdown.html