AUSTIN, June 1, 2014 — June 1 marks the beginning of the 2014 hurricane season. It is a good time to discuss the assertion that human-caused global warming (AGW) is generating more intense hurricanes and in greater numbers — the “hurricane myth.”
The IPCC, the UN body designed to support the United Nations Framework Convention of Climate Change (UNFCCC), abandoned that claim in 2007. It reinforced that conclusion again in the newest AR5 report released last September. It’s right there, plain as a Gulf Coast breeze, in Table SPM.1 on Page 5.
In 2005, AGW theorists seemed to have evidence on their side; the number of intense hurricanes was increasing. But now it’s been 3,142 days since the last major hurricane made landfall in the United States.
The IPCC conclusions on hurricanes are supported by data:
- Total energy released by hurricanes
- Total number of intense hurricanes
- Total number of days between major hurricanes
Total energy release
According to the hurricane myth, the total amount of energy released by hurricanes should be increasing. More warming causes warmer oceans. Hurricanes are powered by the ocean’s heat content.
The logic is impeccable, but it isn’t happening. It hasn’t been for over 15 years.
Dr. Ryan N. Maue, a meteorologist and atmospheric research scientist at Weather Bell Models, calculated the total energy released by all of earth’s hurricanes and typhoons since 1972.
The above chart shows his results as of March 31, 2014. It shows an increase in cyclonic energy of a whopping 38 percent from the early 1970s to 1998.
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However, the data show total hurricane energy has dropped off even faster in the last 15 years. Human-caused atmospheric CO2 has increased roughly 25 percent in that same amount of time.
Maue has also tallied the global total number of all hurricanes of any size and plotted them by year. That recordkeeping goes back to 1978. It shows that the total number of hurricanes and total number of major hurricanes have both decreased by 30 percent since 1997.
Numbers of intense hurricanes
According to the hurricane myth, the number of intense hurricanes should also be increasing.
An intense hurricane is defined as a category 3 or stronger hurricane. Those are the ones AGW theorists say are increasing.
NOAA has tracked all those hurricanes and maintains a publicly accessible database of them. The above chart plots their numbers, tallied by decade, and sports a software-calculated trend line.
Since 1880, the number of intense hurricanes per decade has decreased by about two.
According to the IPCC’s AR5 report, human effects on climate did not become measurable until after 1950. If we plot only since 1950 instead of 1880, then the slope of the downward trend line would be steeper. If not for the last eight seasons when there were no landfalls, the trend line would be roughly flat.
These results are consistent with Maue’s total energy calculations above and his global hurricane counts. The chart is only a regional result that doesn’t reflect the global trend, but Maue’s results suggest that charting the whole planet would produce a similar finding. These data are still inconsistent with the hypothesis that human-caused global warming is generating more intense (Cat 3+) hurricanes than there were in the past.
Number of days between major hurricanes
This last graph plots regional results applied only to the United States, rather than global results. As such, this evidence is not as strong as the Maue and NOAA data.
Further, the trend line is skewed upward by the phenomenal, record-setting 3,142 days since the last major hurricane struck the United States.
Outside the North Atlantic, the Western Pacific is the other major area on earth subjected to many hurricane strength storms. If Pacific storms were included, then the numbers above would be quite different. Perhaps an AGW theorist will chose to do that graph.
The graph is consistent with the other data presented above, and thus supports the conclusion that hurricanes are not becoming more intense, nor more numerous.
IPCC speaks on “extreme weather” hurricane events
Table SPM.1 shows the IPCC assessment for “Increases in intense tropical cyclone activity” (hurricanes).
Translation: There is a lukewarm belief that human activity will increase hurricane activity sometime in the 2nd half of this century.
Note: The IPCC assessment that increases in intense hurricanes is “virtually certain in North America since 1970” is based on exactly one 4-page paper that examines only one year, 2005. It’s titled, “Atlantic hurricanes and natural variability in 2005” by Trenberth, et al.
The IPCC never actually went out and counted hurricanes or added up their total energy to back up that statement, hence the assessment level of “low confidence“.
For the record, NOAA recorded that Superstorm Sandy in 2012 wasn’t a hurricane when it made landfall. It was a huge storm coming ashore at the worst possible place during high tide, which maximized storm surges in vulnerable population centers.
About one foot of Sandy’s 13 foot storm surge has been attributed to sea level rise in worst-case scenarios.
The IPCC doesn’t believe that Sandy, or any other hurricane for that matter, has been caused by human CO2 emissions, so why should anyone else?
Though the IPCC says “no” and the evidence is compelling, it’s likely that the news media will keep the hurricane myth alive and well for years to come.