March 27, 2009 -- Human-produced carbon dioxide in the atmosphere is increasing exponentially, and has been for at least the last 50 years, according to a new study. Using measurements of atmospheric CO2 from the Mauna Loa Observatory in Hawaii, David Hofmann of NOAA's Earth System Research Laboratory in Boulder, Colo. and a team of researchers determined that humanity's contribution of the greenhouse gas has been growing at a steady 2.3 percent since recording began in 1958. At that rate, CO2 doubles every 30 years. The team's findings agree with the 2007 estimate from the United Nations Intergovernmental Panel on Climate Change (IPCC), which predicts that the preindustrial CO2 level of 280 parts per million (ppm) will climb to over 500 ppm by the year 2050 if we keep up our unregulated emissions. At that threshold, global temperatures are expected to be about 3 degrees Centigrade (5.4 degrees Fahrenheit) warmer than preindustrial levels. The effects of global warming like sea level rise, changes in precipitation patterns around the planet, and ocean acidification could endanger coastlines, ecosystems and food supplies. Related Content:
It's unlikely to stop there. Even if the exponential pattern is broken around 500 ppm, CO2 will continue to climb, perhaps up to 750 ppm. Such levels would only amplify the impact of a climate catastrophe. 'The sooner we get off this exponential curve, the better," Hofmann said. Measuring the moment when we start to shed our carbon emitting ways will be a tough -- the first decreases in carbon output will show up not as a decrease in CO2 levels, but only a slower increase. But global population is also growing exponentially, in lockstep with CO2 levels despite the fact that developing countries tend to emit less carbon per capita than the United States or Europe. |
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