"The water temperatures in the Atlantic are also warming"
Please quote your sources.
In the mean time, here is some reading material:
Man Blamed for Rising Sea Temperatures
Recently the news was full of stories about new and stronger evidence that man is causing the planet to warm. The stories were based on two new studies appearing in the April 13 issues of Science. According to Sydney Levitus, lead author of one of the studies, "We think this is some of the strongest evidence to date that human-induced effects are changing our climate" (Associated Press, April 13, 2001).
A closer examination of the studies reveals, however, that the claims are overblown. The studies rely on climate models, which aren’t evidence at all, but merely artificial constructions of what some scientists believe about the climate.
The study by Tim Barnett, et al. attempts to predict the ocean heat content averaged from the surface to 3,000 feet below the surface, from 1955 to 2000, that would result from CO2 forcing. The study claims that the match between the observed warming in the oceans and that produced by the model is very good, therefore suggesting that human activity is responsible for that warming.
To achieve this apparent match, however, the researchers "smoothed" the data by using the average value of each ten-year period rather than the raw data to fit it to the model results. But even the smoothed data does not fit well. Of the five oceans examined, all but one experienced a cooling from the mid-1970s to the mid-1980s not replicated by the models.
The fit between the data and the models is achieved by using ocean temperatures down to 3,000 feet. The model in fact does a terrible job of replicating temperature changes at the ocean’s surface where greenhouse gases have the most immediate effect, but does a very good job of replicating temperatures at depths of 1,500 feet to 3,000 feet, which are largely unaffected by greenhouse gases. The models’s poor performance is hidden by averaging ocean temperatures over 3,000 feet.
The Levitus, et al. study is also questionable. It looks at historical records of ocean temperatures from the surface to 10,000 feet from 1955 to 1996. This study also smooths the data to achieve a better fit, which washes out an important ocean temperature shift that occurred in 1976-77, known as "the great Pacific climate shift."
There was no statistically significant ocean warming before or after the 1976-77 temperature shift. Such sudden shifts can hardly be attributed to gradual increases in greenhouse gas concentrations, but by averaging the data, Levitus, et al. were able to construct a gradual temperature rise consistent with global warming theory.
More detailed criticisms of the studies can be found at www.john-daly.com and www.greeningearthsociety.org/climate. |
