A look at Dr. Ryan Maue’s site here tells us a lot about how 2017 cyclone activity is doing as the Atlantic hurricane season winds down.
In September the Atlantic indeed saw some powerful hurricanes, such as Harvey, Irma and Maria, which led the media into a fit of Armageddon hysteria and calls to do something about climate change. It is true that the Atlantic saw an unusually active hurricane season, some 227% of what is normal in terms of energy, but the Atlantic is not the global situation.
Table showing 2017 accumulated cyclone energy for the 7 main basins globally. Source: Dr. Ryan Maue.
As the chart above shows, global accumulated cyclone energy (ACE) is currently running 19% below average and is only 73% of what it was at this time one year ago (2016).
This seems to fly in the face of all the warnings suggesting that global warming would intensify storm activity. Naturally 2017 is only one single year, and so it’s necessary to look at longer term trends.
Lowest levels since 1970s, frequency at a “historical low”
At his site Maue refers to an abstract of a paper: Geophys. Res. Lett. (2011) which tells us that cyclones don’t seem to be correlating with atmospheric CO2 at all:
In the pentad since 2006, Northern Hemisphere and global tropical cyclone ACE has decreased dramatically to the lowest levels since the late 1970s. Additionally, the frequency of tropical cyclones has reached a historical low.”
Downward cyclone trend over the past 25 years. Source: Dr. Ryan Maue.
Southern hemisphere near record low
Obviously there’s a lot more behind cyclones than CO2. So far the southern hemisphere is near a record low, running only at 44% of what is normal.