Has a Runaway Greenhouse Effect Begun? (Adapted)
By Norm Dixon
Urgent Action for Governments
In recent weeks, scientists have released two separate findings that indicate the consequences of global warming due to the emission of 'greenhouse gases' primarily carbon dioxide (CO2) from the industrial burning of fossil fuels may be far greater than previously estimated.
The new findings stress the need for governments around the world, in particular the industrialized First World countries that are responsible for more than 80% of past emissions and 75% currently, to take urgent action to massively reduce the world's industrial greenhouse gas emissions by 60-80%.
Rajendra Pachauri, chairperson of the United Nations' Intergovernmental Panel on Climate Change (IPCC), which pools the expertise of more than 2,000 of the world's climate scientists, warned on October 25 that the greenhouse gas emission reduction targets established in the 1997 Kyoto agreement do not go far enough and far more radical solutions must be found.
Pachauri welcomed the Russian parliament's October 22 approval of the Kyoto agreement, which will allow the treaty to come into legal force despite the refusal by the world's major polluter, the United States, to sign．However, 'this mustn't deceive us into thinking that the problem is solved', Pachauri told Reuters(路透社)．'Kyoto is not enough．We have to look at the problem afresh．'The Kyoto treaty aims for a reduction in greenhouse gas emissions of around 5% of 1990 levels, far short o{ the 60-800/oo over the next 50 years necessary to arrest global warming．
CO2 Accumulation Increasing
The new evidence on the pace of global warming suggests that world governments may have even less time to act than previously estimated．The October 11 British Guardian(英国卫报) reported that CO2 in the atmosphere is at record levels and increasing at an accelerating rate, while the September 23 edition of Science revealed that glaciers in western Antarctica flowing into the sea are speeding up, indicating an increased level of melting.
The scientists who make up the IPCC estimate that unless levels of greenhouse gases in the atmosphere are stabilized by mid-century, Earth's average temperature will rise by up to 5.8~C by 2100．According to the IPCC figures, if unchecked, CO2 levels in the air will be between 650 and 970 parts per million (ppm)．However, these estimates may be too conservative.
According to the October 11 Guardian, measurements of average atmospheric CO2 levels in 2002 and 2003 may confirm that the rate of CO2 accumulation is now increasing at an alarming rate．Scientists at Hawaii's Mauna Loa Observatory(气象台) reported that average CO2 levels increased by 2.08 ppm in 2002, to 373.1 ppm, and in 2003, to an average of 375. ppm．This is the first recorded example of the average CO2 level jumping more than 2 ppm in two successive years．The average increase in the CO2 level over the last few decades, reports the Guardian, has been 1.5 ppm．The current level of CO2 is the highest in at least 420,000 years!
Associated Press (美联社) reported earlier this year, on March 20, that scientists at Mauna Loa Observatory had recorded the CO2 level in the atmosphere peaking at a record of 379 ppm, compared to 376 ppm a year earlier and 373 ppm in 2002．
Global Warming
The increase has implied a 'runaway' greenhouse effect already underway．Previous increases of CO2 levels of above 2 ppm—1973, 1988, 1994 and 1998—have coincided with the El Nino(厄尔尼诺现象) weather pattern in the Pacific．However, this cannot explain the latest rises.