Floodwaters from Hurricane Katrina fill the streets near downtown New Orleans, La., on Aug. 30, 2005. (AP Photo/David J. Phillip)

THIS POST EXAMINES THE CLIMATE SCIENCE POSITION THAT THE USE OF FOSSIL FUELS HAS INCREASED THE DESTRUCTION CAUSED BY TROPICAL CYCLONES. 

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1. The claimed causal connection between AGW climate change and the destructiveness of tropical cyclones did not emerge from the science nor from an extensive study of historical data but from an unlikely event in 2005 when Hurricane Katrina damaged a levee system that had not been properly maintained. The damage to the levee caused a catastrophic flooding of New Orleans that became the signature issue in the destructiveness of Hurricane Katrina as seen in the 2005-2009 reports in paragraph#2 below. The role of levee management in the destruction was downplayed and forgotten and the entire destruction was thus attributed to fossil fueled climate change with the subsumed climate action lesson of Katrina being that such destruction can and must be attenuated by reducing and eventually eliminating the use of fossil fuels.
2. Hurricane Katrina Historical Notes: (i) HURRICANE KATRINA IS THE HARBINGER OF WORSE YET TO COME: The IPCC claimed that it had the scientific evidence to prove that our use of fossil fuels caused Hurricane Katrina to forecast with a great certainty that there was more to come in the 2006 hurricane season but the 2006 hurricane season turned out to be milder than normal. The IPCC blamed the dissipation of El Nino for the mild hurricane season in 2006 and issued a new warning that 2007 will be the hottest year on record and will bring a killer hurricane season worse than 2005 but the 2007 forecast also failed. The IPCC’s dream hurricane season has finally arrived in 2008 unannounced and unexpected with strong hurricanes Gustav and Hanna expected to be followed by Ike and a dozen others before the season is through. More info: [LINK] . (ii) The IPCC’s claim that Hurricane Katrina was caused by man-made global warming has been thoroughly discredited and their forecasts for more severe hurricane seasons in 2006 and 2007 have been proven wrong. They are merchants of fear and their method is the dissemination of convenient lies. More info: [LINK] . (iii) Climate science shows that AGW climate change is increasing the frequency and severity of extreme weather as for example Hurricane Katrina. Further research shows a causal link between AGW and increasing wave intensity that provides direct evidence of the extreme weather impacts of AGW. More info: [LINK] . (iv) 2009: In 2005 climate science declared that Hurricane Katrina was the harbinger of killer super storms yet to come created by fossil fueled global warming but after no further cyclone activity in the North Atlantic Basin in the next three years, new evidence for the destructiveness of AGW extreme weather was found in Cyclone Nargis in the North Indian Basin. Though not unusually strong, Nargis did create a freak storm surge in rising tides that swept up the Irrawaddy River in Burma and claimed a horrific death toll. Nargis thus became an AGW issue and climate scientists changed their extreme weather focus from the North Atlantic Basin to the North Indian Basin saying that Cyclone Nargis was a creation of climate change caused by fossil fuel emissions and as the harbinger of “destruction on a global scale” by human caused global warming. More [LINK] .
3. The Climate Science of Hurricane Katrina:  It was thus that the climate science of the destructiveness of hurricanes did not predict Katrina but was in fact constructed from Katrina based only on the destructiveness of the flood caused by the break in the levee system and by discounting the greater climatology data that it was Wilma, not Katrina, that was by far the stronger hurricane of the 2005 season but Katrina, not Wilma, was clearly the better tool to sell AGW’s fear based climate action agenda. This relationship between climate science and real science is seen more clearly in the foundational and keynote paper by noted MIT climate scientist Professor Kerry Emanuel reviewed in detail in a related post [LINK] . There it is shown that the need by climate science to establish the fear of climate change in terms of hurricanes made it possible for Professor Emanuel to abandon all pretension to scientific principles and statistical rigor to publish in a peer reviewed journal a circular reasoning paper that begins with the assumption that AGW increases the destructiveness of hurricanes and then proves that AGW increases the destructiveness of hurricanes [LINK] .
4. Yet another issue is that the single minded focus on the North Atlantic Basin (NA) for the detection of the impact of climate change on tropical cyclone destructiveness during periods when NA is unusually active is a form of circular reasoning; particularly so because NA by itself is not a globally important source of cyclone energy. An additional consideration is the finding by Knutson (2010) and others that total cyclone energy variance for a single basin is too large to come to meaningful conclusions about trends and recommended that only the aggregate of all six basins could contain useful trend information.
5. Knutson, Thomas R., et al. “Tropical cyclones and climate change.” Nature geoscience 3.3 (2010): 157-163. In the paper, Tom Knutson spells out exactly what climate science claims in terms of the impact of AGW climate change on tropical cyclones with climate model predictions of the effect of rising SST on tropical cyclones. His main points are as follows: (1) Globally averaged intensity of tropical cyclones will rise as AGW increases SST. Models predict globally averaged intensity increase of 2% to 11% by 2100. (2). Models predict falling globally averaged frequency of tropical cyclones with frequency decreasing 6%-34% by 2100. (3). The globally averaged frequency of “most intense tropical cyclones” should increase as a result of AGW. The intensity of tropical cyclones is measured as the ACE (Accumulated Cyclone Energy). (4). Models predict increase in precipitation within a 100 km radius of the storm center. A precipitation rise of 20% is projected for the year 2100. (5) Extremely high variance in tropical cyclone data at an annual time scale suggests longer, perhaps a decadal time scale which in turn greatly reduces statistical power. (6) Model projections for individual cyclone basins show large differences and conflicting results. Thus, no testable implication can be derived for studies of individual basins.
6. There are six tropical cyclone basins in the world where tropical cyclones form.  These are the West Pacific (WP), South Indian Ocean (SI), East Pacific (EP), North Atlantic (NA), North Indian Ocean (NI), and the South Pacific (SP). The most intensive and active  basin is the West Pacific Basin where tropical cyclones are called Typhoons. The North Atlantic Basin, where tropical cyclones are called Hurricanes, is a lesser basin and not a significant source of total global cyclone energy. Of the other four basins, the South Indian Ocean basin is the most active. Together, WP and SI generate more than 60% of the total global cyclone energy with the East Pacific and the North Atlantic together coming in second with about 25% of the world’s cyclone energy. The North Atlantic generates about 14% of the world’s cyclone energy. The details of this comparison are tabulated below.
7. 
8. Since AGW climate change is proposed as a global phenomenon, its effect on tropical cyclones must be studied and understood only in terms of global measures of tropical cyclone activity and not in terms of convenient localized phenomena that fit the narrative or that might derive from a USA bias of American researchers and the American news media. Here we provide an integration and summary of three related posts where the global impact of AGW on tropical cyclone activity is measured as a global aggregate of all six cyclone basins.
9. Study#1 > Trends: [LINK] . The trend study presents data for total cyclone energy for all six basins for the 70-year study period 1945 to 2014. The object variable is the Accumulated Cyclone Energy (ACE) used as a measure of total cyclone energy. Knutson (2010) and others have suggested that year to year variance in cyclone energy is too large and random to draw meaningful interpretation of and recommended a decadal time scale for the study of tropical cyclone trends. Accordingly, the total global ACE for all six cyclone basins is computed for each of the seven decades in the 70-year study period. Trend analysis is carried out by comparing each decade against the other six. The results are summarized in the Table presented in Paragraph#9 below. They show that only two statistically significant differences are found. Specifically, we find that Decade#5 (1985-1994) and Decade#6 (1995-2004) show higher total global cyclone energy than Decade#1 (1945-1954). No other statistically significant difference is found among the seven decades studied.
10. 
11. It is tempting here to conclude that the higher global cyclone energy in the two recent decades from 1985 to 2004 than in the decade 1945-1954 can and should be attributed to AGW climate change but there are other well understood considerations that explain this difference. It is well established and generally accepted in the tropical cyclone research community that the early decade in this study, 1945-1954, suffered from a measurement bias such that not all tropical cyclones were detected and of those that were not all were adequately measured. In other words the early data are incomplete and the incompleteness of the data provides a stronger and more rational explanation of the observed statistically significant trend in total cyclone energy. We conclude from these results that he data do not show an impact of AGW climate change in the form of increasing the destructiveness of tropical cyclones. 
12. Study #2: > SST: [LINK] . Sea surface temperature (SST) is the link that connects climate change with tropical cyclone activity with the proposition that higher SST provides more energy for tropical cyclones that form on the basis of high SST. Cyclone theory tells us that cyclone formation, and intensification are related to SST (Vecchi, 2007) (Knutson, 2010). Testable implications of the theory for empirical research are derived from climate model simulations (Knutson, 2010). Knutson’s work also suggests that the high variance in tropical cyclone activity at an annual time scale or for any single cyclone basin means that data analysis must be carried out on a global basis for all six tropical cyclone basins and time scales longer than annual should be used. Detrended correlation analysis for total cyclone energy and SST are carried out at a decadal time scale 1945-2014. The results are tabulated in Paragraph#12. They show that the high correlation seen between total global cyclone energy (ACE) and global sea surface temperature (SST) derives from a rising trend in both time series and not from a responsiveness of ACE to SST at a decadal time scale.
13. 
14. We conclude from the results presented in Paragraph#8 to Paragraph#12 that no evidence is found for the usual assumption in climate science that AGW climate change is intensifying tropical cyclone activity by way of SST.
15. Study#3: > Pre-Industrial: [LINK] . The fundamental theoretical  basis for the theory of AGW climate change is a stark difference between “pre-industrial times” and the “era of the industrial economy” in terms of climate as assumed in climate science. A testable implication of the claimed impact of AGW climate change on tropical cyclones in terms of this dichotomy is that a comparison of the two eras should show a stark difference in tropical cyclone activity in terms of an absence of intense and destructive tropical cyclones in the pre-industrial era.
16. The Treasure Coast Hurricanes of 1715 & 1733, The Dreadful Hurricane of 1667, The Calcutta Cyclone of 1737, The Great Hurricane of 1780, The Great September Gale of 1815, The Coringa Cyclone of 1839, and The Last Island Hurricane of 1856, The San Diego Hurricane of 1858 are described and presented as tropical cyclones with intensity and destructiveness comparable to the high profile hurricanes cited by climate science as evidence of the impact of AGW climate change. We conclude from the comparison that it does not provide convincing evidence that tropical cyclones such as the destructive hurricanes cited by climate science as a creation of AGW are unique to the industrial economy that could not have occurred in pre-industrial times. It is also noted that the strongest and most destructive tropical cyclone of the post industrial era was the monster Bhola Cyclone [LINK][LINK]that killed half a million people in Bangladesh. It occurred way back in 1970 right in the middle of the 1970s cooling period[LINK]that had sparked fears of a return to Little Ice Age conditions[LINK] .
17. CONCLUSION: The data and their interpretation presented in these posts reveal serious weaknesses in the claim by climate science that the industrial economy has caused greater intensity and destructiveness of tropical cyclones by way of global warming and rising sea surface temperature. The abstract from the Knutson 2010 paper listed in the bibliography below provides the basis for the study of tropical cyclones in the global warming context. It says as follows: 
18. Tropical cyclones and climate change.” Nature geoscience 3.3 (2010): 157-163. In the paper, Tom Knutson spells out exactly what climate science claims in terms of the impact of AGW climate change on tropical cyclones with climate model predictions of the effect of rising SST on tropical cyclones. His main points are as follows: (1) Globally averaged intensity of tropical cyclones will rise as AGW increases SST. Models predict globally averaged intensity increase of 2% to 11% by 2100. (2). Models predict falling globally averaged frequency of tropical cyclones with frequency decreasing 6%-34% by 2100. (3). The globally averaged frequency of “most intense tropical cyclones” should increase as a result of AGW. The intensity of tropical cyclones is measured as the ACE (Accumulated Cyclone Energy). (4). Models predict increase in precipitation within a 100 km radius of the storm center. A precipitation rise of 20% is projected for the year 2100. (5) Extremely high variance in tropical cyclone data at an annual time scale suggests longer, perhaps a decadal time scale which in turn greatly reduces statistical power. (6) Model projections for individual cyclone basins show large differences and conflicting results. Thus, no testable implication can be derived for studies of individual basins.

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