Researchers at Florida State University announced that global hurricane activity continues to decrease and is now at levels not seen since 1977. The researchers say that, “Tropical cyclone (TC) activity worldwide has completely and utterly collapsed during the past 2 to 3 years.”
Last November we reported that hurricane activity in the northern hemisphere was at 30 year lows. Now, in this follow-up research, we see that when including the southern hemisphere global hurricane energy has sunk to 30 year lows. Using a measurement called the Accumulated Cyclone Energy index (ACE), researchers see a tremendous drop in cyclone energy for the globe as a whole. While the north Atlantic saw above normal levels of ACE in 2008, it represents a relatively small amount of the global hurricane energy and as such cannot compensate for the much reduced levels elsewhere on Earth.
The researchers believe the reduction in activity can be traced to a strong La Nina event (cooling of the Pacific) that in turn typically results in fewer and less powerful storms in the Pacific. They caution that conversely La Nina does typically produce above normal levels of activity in the Atlantic so 2009 could be an active season for areas of the United States.
The reduced activity does go counter to predictions that severe weather and hurricane activity would increase as a result of global warming. Researchers did specifically address the contradiction stating that those types of conclusions were unproven and much more research needs to be done before making such claims. They said, “Under global warming scenarios, hurricane intensity is expected to increase (on the order of a few percent), but MANY questions remain as to how much, where, and when. This science is very far from settled. Indeed, Al Gore has dropped the related slide in his PowerPoint [presentation].”