Is the recent rash of Atlantic hurricanes just a band of rogues or an army on the march? A new study in this week’s journal Science says it’s the latter.
As this ScienCentral News video reports, it’s a dire forecast for the eastern United States and the Caribbean.
How can they be sure?
Do Goldenberg et al really have enough data to be confident of their forecast? In a "Perspectives" essay in Science, Lannart Bengtsson of the Max Planck Institute for Meteorology in Germany concludes that they don’t. "The records are too short and incomplete to claim that the coastal United States may be in for a longer period of high hurricane activity," writes Bengtsson.
The report looks at two climate factors with a big impact on the numbers, and power, of hurricanes. Warmer sea surface temperatures tend to fuel Atlantic hurricanes, while large vertical wind shears can kill them. When the team compared long-term cycles of sea surface temperature and wind shear, they matched periods of low, and high, hurricane activity. Those long-term cycles "fluctuate on a very long timescale," Goldenberg says, "on the order of anywhere from say 30 to 60 or 80 years or so."
And Goldenberg says other sources of data convinced them that the cycle is real. "The overall hurricane activity in the Atlantic is reliable back to about the mid-40’s when consistent aircraft reconnaissance began. We linked that up to these fluctuations in sea surface temps. Well, the sea surface temperature cycles, that data is reliable back to the late 18-hundreds, so therefore we have almost 2 cycles. Well, that still may be a relatively short record. Well, we matched that up to other type of what we call proxy data, modeling data that extend back literally to the 16-hundreds and we see this consistent cycle go back," Goldenberg says.
Not enough funding?
Longterm forecasts don’t do much for a community in the path of a hurricane. That’s when NOAA’s tracking and intensity warnings guide lifesaving evacuations. NOAA scientists who warn that the threat is now high also agree that funding for this critical research is way too low.
Due to budget contraint, last year researchers did not fly into a single hurricane for the first time in almost 40 years. A letter prepared by the five living former directors of the National Hurricane Center describes the shortfall:
"Despite [its] achievements, base funding for Hurricane Research Division (HRD) has not increased for the last two decades and its purchasing power has been severely eroded by inflation and increased overhead costs. Because of the lack of funding, the scientific staff has decreased from 40 to 26 federal employees and will continue to decline without new financial support. Another consequence of inadequate funding is that HRD has not been able to upgrade crucial computer equipment that is necessary to expedite its research. Furthermore, key investigations of hurricane motion, rainfall distribution, and rapid intensification are slow to be transitioned to operations at the National Hurricane Center."
"Our funding is going down and down," Goldenberg says. "We are wondering if our lab is going to continue to exist. It’s that bad."