Is Global Warming Causing Hurricanes?

Of all the claims that the alarmists make on behalf of anthropogenic global warming, perhaps the most outrageous is that hurricanes–think Katrina–are becoming more frequent and more severe as a result of human activity. Actually, hurricanes have not become either more frequent or more violent, which one might think would put the issue to rest. But the alarmists know they have reporters on their side, so inconvenient truths won’t be mentioned.

If you want to read all there is to know on this subject, check out this paper by Dr. William Gray, America’s leading expert on hurricanes. He minces no words in denouncing the fraudsters who have come to dominate climate “science.”

The US government has expended billions of dollars in recent years to promote the questionable idea that human-induced increases in atmospheric CO2 will cause dangerous changes to the global climate system. Massive government and media campaigns have been launched to promote the dangers of CO2-induced anthropogenic global warming (AGW) and related influences such as the anticipated increases in global tropical cyclone (TC) frequency and intensity as well as other severe weather events. Pro-AGW advocates have pushed to have this warming gospel accepted across the world and taught to our children in their regular school programs. AGW advocates want to worry the public as much as possible in order to be better able to increase their influence and funding support. …

After the very severe US hurricane landfalling seasons of 2004 and 2005, the public was more open and vulnerable to such arguments of CO2 induced increases in hurricane activity. A group of papers were rapidly published to exploit and to justify this assumption so that the authors might be able to jump onto the warming bandwagon and increase their potential for more federal grant support, publicity, and other envisioned gains.

Dr. Gray points out the obvious facts that refute the alarmists’ claims:

Although global surface temperatures appear to have increased during the 20th century by about 0.65°C or 1°F, there is no reliable data to indicate that increases in TC frequency or intensity changes occurred in any of the globe’s TC basins. Global Accumulated Cyclone Energy (ACE)1 shows significant year-to-year and decadal variability over the past 40 years (when global TC data is deemed reasonably reliable) but no period-long increasing trend. In fact, global TC activity has shown (red line) a distinct decrease over the last 20 years when CO2 amounts were increasing (Figure 2.1). Similarly, Klotzbach (2006) found no significant change in global TC activity during the period from 1986-2005 when tropical SSTs and CO2 amounts were rising (Figure 2.2). See section 13 for more discussion.

Then there is this; there were more Caribbean hurricanes during the era of global cooling than the era of global warming:

Dr. Gray explains in detail why the alarmists’ reasoning is wrong; they don’t know much about hurricanes. They seize on the fact that hurricanes currently intensify when they pass over warmer ocean water, and assume that warmer temperatures mean bigger hurricanes. They completely ignore the fundamental difference between warmer water in the current environment, and a climate that is a degree warmer:

CONFUSING LOCAL AND CLIMATE TIME SCALES. A hurricane passing over a warmer body of water, such as the Gulf Stream, will often undergo a degree of intensification. This is due to the sudden lapse rate increase which the hurricane’s inner core experiences when it passes over warmer water. The warmer SST causes the hurricane’s inner-core PBL temperature and moisture content to rise. While these low-level changes are occurring, upper tropospheric conditions are typically not being altered. These rapidly occurring lower- to upper-level potential buoyancy increases can cause the inner-core hurricane lapse-rates to increase and likely produce more inner-core deep Cb convection. This can cause an increase in the hurricane’s intensity. Such observations and the clear association of the most intense individual typhoons and hurricanes with the highest SSTs has led many observers to directly correlate SST with hurricane intensity on longer-period climate scales. This is valid reasoning for local and day-to-day hurricane intensity changes that are associated with hurricanes moving over warmer or colder patches of SST. But such direct reasoning does not hold for conditions occurring in a climatologically altered tropical ocean environment where upper tropospheric temperature and moisture conditions have had time to become adjusted to a warmer or cooler and moister or dryer PBL. Such balancing upper and lower tropospheric mutual adjustments inhibit lapse-rate alteration. We should not expect that the frequency and/or intensity of Cat. 4-5 hurricanes will necessarily change if the globe should become somewhat warmer or somewhat cooler.

This analysis is contrary to the general physical reasoning of the many papers listed in Table 3.1. Most of these papers hypothesize a climatologically direct linkage between rising SST values and rising levels of TC activity. This is not a valid assumption on a climate change time scale.

EVIDENCE OF LITTLE SST-TC ASSOCIATION ON SEASONAL TIME SCALES. The physics of those proposing a direct physical link between rising levels of CO2 and TC activity is given in Figure 10.10. This is a plausible physical argument over a short period. But on the climate time-scale the assumed linkage between steps 3 to 6 is not valid.

Gray’s article is detailed and technical; I couldn’t follow it all. But the mistakes that the alarmists make are so childish that any intelligent observer can see what is going on.

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