What causes the unusually strong hurricane season of 2005? There are two theories: rising sea surface temperature and natural ocean cycles (such as El Niño)
A new scientific study suggests that rising sea surface temperature caused by global warming is responsible, instead of natural ocean cycles.
Using worldwide SST data since the early 20th century, Trenberth and Shea calculated the individual contributions of global warming and the AMO to Atlantic SSTs. They subtracted the irregular Atlantic temperatures from the temperature patterns in the rest of Earth's tropical and mid-latitude waters.
Their calculations show that about half, or 0.81 degrees Fahrenheit, of the Atlantic SST increase was due to global warming, while only 0.2 degrees owed to the AMO. The remainder of the increase could be explained by the aftereffects of the 2004-2005 El Nino and normal year-to-year variations in temperatures.