Surface temperatures in the past two decades have risen at a rate substantially greater than average for the past 100 years, says a new report by the National Research Council of the National Academies. The report examines the apparent conflict between surface temperature and upper-air temperature, which has led to the controversy over whether global warming is actually occurring. Fahrenheit - in the last century, the report says. Climate models generally predict that temperatures should increase in the upper air as well as at the surface if increased concentrations of greenhouse gases are causing the warming. Sea surface temperatures January 13, 2000.
Red color indicates warmer, blue color, the cooler temperatures.
The panel recommends that nations of the world should develop an improved climate monitoring system to resolve uncertainties in the data and provide policy-makers with the best available information. For example, natural events such as the eruption of Mt. Pinatubo in 1991 tended to decrease atmospheric temperature for several years. And burning coal and oil for energy produces tiny aerosol particles in the atmosphere that can have a cooling effect. Upper-air temperatures also can be reduced by depletion of ozone in the stratosphere caused by chlorofluorocarbons and other chemicals being emitted into the atmosphere. When these variables are accounted for in atmospheric models, satellite and balloon data more closely align with surface-temperature observations.