Michael Le Page in New Scientist:
In the past decade, five tropical storms had wind speeds so high that they should have been classified as “category 6” storms, according to an analysis that suggests the hurricane scale may need to be updated as rising temperatures fuel stronger storms.
If carbon emissions continue at current rates, we might even see “category 7” storms. “It certainly is theoretically possible if we keep warming the planet,” says climate scientist James Kossin at the First Street Foundation, a non-profit research organisation in New York.
Officially, there is no such thing as a category 6 or category 7 hurricane. According to the Saffir-Simpson hurricane scale used by the National Hurricane Center (NHC) in the US, any storm with sustained wind speeds of 252 kilometres per hour and over is a category 5.
But as the wind speeds of the strongest storms get faster, the use of this scale is increasingly problematic, say Kossin and his colleague Michael Wehner at the Lawrence Berkeley National Laboratory in California, as it doesn’t convey the increasing risks posed by ever stronger storms.
More here.