Friday, September 6, 2019
Over the past two decades, 2000–18, there has been an increase of one to two named hurricanes per year over the rates experienced during the three decades between 1960 and 1989—or, expressed differently, an increase of perhaps one per year over the long-term average of 6.3 going back to 1950. At the same time, the current rates of seven named hurricanes per year are very close to the rates (6.9 per year) experienced during the 1950s.
As with the data cited by David Leonhardt above, there has been a real increase in the number of hurricanes forming over the past three decades, but only if we compare these rates to the unusually low number of hurricanes formed in the 1970s and 1980s. If we move the reference point back into the 1950s, the rate of increase flattens out and nearly disappears—with average annual rates of 6.9 per year from 1950 to 1959 and an identical annual rate between 1990 and 2018.
Conclusion: There has been a modest increase in the number of hurricanes formed per year since 2000, but these rates are not significantly higher than the long-term average and are very close to the rates experienced in the 1950s.
I've been wondering about this. What happened in the Bahamas is terrible of course. But it doesn't mean hurricanes are getting any more frequent. They might be, but they might not as well. Where the pressure is building up is in the minds of global climate change affirmers.