Global Heating Gases Increased by 20% in 15 years

[excerpts; full story here]

The effect of greenhouse gases on the Earth's atmosphere has increased 20 percent since 1990, a new government index says.

In its new analysis the laboratory, a branch of the National Oceanic and Atmospheric Administration, compares the amounts of carbon dioxide, methane, nitrous oxide and chlorofluorocarbons in the air. Those gases have been sampled for many years. The index was set to a reading of 1 as of 1990 and the lab said it is currently 1.20, indicating an increase of 20 percent.

"The AGGI will serve as a gauge of success or failure of future efforts to curb carbon dioxide and other greenhouse gas increases in the atmosphere both by natural and human-engineered processes," said David Hofmann, CMDL director.

The lab said most of the increase measured since 1990 is due to carbon dioxide, which now accounts for about 62 percent of the radiative forcing by all long-lived greenhouse gases.

The Earth's average temperature increased about 1 degree Fahrenheit during the 20th

century. The Intergovernmental Panel on Climate Change warns that continuing increases could have serious effects on crops, glaciers, the spread of disease, rising sea levels and other changes.