In a new analysis of bubbles trapped in Antarctic ice, published Thursday in Science, lead author Frederic Parrenin of the Laboratory of Glaciology and Geophysics of the Environment, in Grenoble, France, and his colleagues write that at the end of the last ice age, about 20,000 years ago, â. . . Antarctic temperature did not begin to rise hundreds of years before the concentration of CO2, as has been suggested in earlier studies.â
âScientists had been saying the CO2 was an amplifier of global warming, but not the initial cause,â Parrenin said. âNow weâre saying it could be the cause.â
This doesn't mean CO2 isnât an amplifier as well. If the oceans warm, basic chemistry says that some of the carbon dioxide dissolved in the water will emerge into the atmosphere. And if the permafrost that covers about a quarter of the Northern Hemisphereâs land surface melts, it will put enormous amounts of carbon dioxide (plus methane, an even more powerful greenhouse), into the atmosphere as well.
âI think theyâve taken a big step toward getting this right,â said Edward Brook, a paleo-climatologist at Oregon State University, in an interview. Brook also wrote a commentary on the research for Science, and he cautioned in that commentary that âWe . . . do not know whether the results can be generalized to other time periods.â
Still, if there remained any doubt that CO2 itself could initiate global warming, this paper â along with a 2012 paper that also showed no time lag â should go a long way toward putting that doubt to rest.
The time lag suggested by those earlier studies didnât call into question the well-established relation between CO2 and warming, and did nothing to lessen scientistsâ confidence â and fear â that without curbing human greenhouse-gas emissions, global temperatures will continue to rise dangerously through the rest of this century. Nevertheless, the new research emphasizes that the CO2-warming relationship could be somewhat more straightforward in some ways than previously thought.
http://www.huffingtonpost.com/2013/...pheric-carbon-dioxide_n_2792149.html?ir=Green
âScientists had been saying the CO2 was an amplifier of global warming, but not the initial cause,â Parrenin said. âNow weâre saying it could be the cause.â
This doesn't mean CO2 isnât an amplifier as well. If the oceans warm, basic chemistry says that some of the carbon dioxide dissolved in the water will emerge into the atmosphere. And if the permafrost that covers about a quarter of the Northern Hemisphereâs land surface melts, it will put enormous amounts of carbon dioxide (plus methane, an even more powerful greenhouse), into the atmosphere as well.
âI think theyâve taken a big step toward getting this right,â said Edward Brook, a paleo-climatologist at Oregon State University, in an interview. Brook also wrote a commentary on the research for Science, and he cautioned in that commentary that âWe . . . do not know whether the results can be generalized to other time periods.â
Still, if there remained any doubt that CO2 itself could initiate global warming, this paper â along with a 2012 paper that also showed no time lag â should go a long way toward putting that doubt to rest.
The time lag suggested by those earlier studies didnât call into question the well-established relation between CO2 and warming, and did nothing to lessen scientistsâ confidence â and fear â that without curbing human greenhouse-gas emissions, global temperatures will continue to rise dangerously through the rest of this century. Nevertheless, the new research emphasizes that the CO2-warming relationship could be somewhat more straightforward in some ways than previously thought.
http://www.huffingtonpost.com/2013/...pheric-carbon-dioxide_n_2792149.html?ir=Green
