Hurricane Intensity: An Example of Global Warming Alarmism

Recently, I have given examples of why I believe global warming is real. I
now want to give an example where I believe the case is oversold. The (less
famous) :-) Dr. Gray from Colorado State cogently explains why global
warming does not explain current hurricane intensities. There have been a
flurry of papers that conclude the other way recently nevertheless Dr. Gray
is holding his own. We shall see who prevails as the research continues.

http://hurricane.atmos.colostate.edu/Forecasts/2005/dec2005/

> There is no physical basis for assuming that global hurricane intensity or
> frequency is necessarily related to global mean surface temperature changes
> of less than ± 0.5oC. As the ocean surface warms, so too does global
> upper air temperatures to maintain conditionally unstable lapse-rates and
> global rainfall rates at their required values. Seasonal and monthly
> variations of sea surface temperature (SST) within individual storm basins
> show only very low correlations with monthly, seasonal, and yearly
> variations of hurricane activity. Other factors such as tropospheric
> vertical wind shear, surface pressure, low level vorticity, mid-level
> moisture, etc. play more dominant roles in explaining hurricane variability
> than do surface temperatures. Although there has been a general global
> warming over the last 30 years and particularly over the last 10 years, the
> SST increases in the individual tropical cyclone basins have been smaller
> (about half) and, according to the observations, have not brought about any
> significant increases in global major tropical cyclones except for the
> Atlantic which as has been discussed, has multi-decadal oscillations driven
> primarily by changes in Atlantic salinity. No credible observational
> evidence is available or likely will be available in the next few decades
> which will be able to directly associate global surface temperature change
> to changes in global hurricane frequency and intensity.
>

Some comments from the peanut gallery. Note that Dr. Gray admits that global
warming is real. He notes what I mentioned previously that global warming is
far less pronounced in the tropics than the poles such that the
SST increases in the tropical basins are half of the overall average. If
there was more warming in the basins then it would be a more significant
effect. For now, it's swamped by other factors. The other thing to note is
the discussion of thermohaline circulation as the primary driver of
hurricanes. Recall my previous post, ice cap melting makes this less
pronounced. This means that global warming produces two countervailing
effects on hurricanes. Just like global warming might produce a slightly
cooler Europe because of a less pronounced Gulf Stream (this is nowhere near
the "Day after Tomorrow" scenario), it is altogether possible that global
warming may actually produced SMALLER HURRICANES! So much for the alarmists.

Dr. Gray appears to be focusing on the effects of global warming and
hurricanes and focusing less on the yearly forecast. I look forward to
seeing his upcoming work.
Received on Wed Apr 26 11:30:18 2006