How does rising atmospheric CO2 affect marine organisms?

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A Long-Term Record of Tropical Cyclones and Hurricanes of Louisiana, USA
Mock, C.J. 2008. Tropical cyclone variations in Louisiana, U.S.A., since the late eighteenth century. Geochemistry, Geophysics, Geosystems 9: 10.1029/2007GC001846.

What was done
The author developed a "unique documentary reconstruction of tropical cyclones for Louisiana, U.S.A. that extends continuously back to 1799 for tropical cyclones, and to 1779 for hurricanes." This record -- which was derived from daily newspaper accounts, private diaries, plantation diaries, journals, letters and ship records, and which was augmented "with the North Atlantic hurricane database as it pertains to all Louisiana tropical cyclones up through 2007" -- is, in Mock's words, "the longest continuous tropical cyclone reconstruction conducted to date for the United States Gulf Coast."

What was learned
Mock reports that "the 1820s/early 1830s and the early 1860s are the most active periods for the entire record."

What it means
Once again quoting the University of South Carolina researcher, "the modern records which cover just a little over a hundred years is too short to provide a full spectrum of tropical cyclone variability, both in terms of frequency and magnitude." In addition, he states that "if a higher frequency of major hurricanes occurred in the near future in a similar manner as the early 1800s or in single years such as in 1812, 1831, and 1860, [they] would have devastating consequences for New Orleans, perhaps equaling or exceeding the impacts such as in hurricane Katrina in 2005." And, of course, the new record clearly indicates that the planet's current high levels of both air temperature and CO2 concentration cannot be blamed for the 2005 Katrina catastrophe, as both parameters were much lower than they are currently when tropical cyclone and hurricane activity in that region were much higher than they are now back in the early to mid 1800s.

Reviewed 25 June 2008