Atmospheric concentrations of carbon dioxide reached an all-time high of 389 parts per million in 2010 and rose at a faster pace than in previous years, according to a report issued Nov. 21
by the World Meteorological Organization, the U.N.’s weather agency. The report stated that global CO2 levels are now 39 percent higher than they were at the start of the industrial revolution in 1750, when levels were at approximately 280 ppm. Those concentrations had remained relatively stable for 10 thousand years previously, according to climate researchers.
Carbon dioxide levels rose at a rate of 2.3 ppm between 2009 and 2010. That was faster than the average rate during the previous decade of about 2.0 ppm per year, and a significant acceleration compared to the average during the 1990’s, when concentrations rose about 1.5 ppm per year.
The annual WMO report assessed the burdens and rates of several other greenhouse gases that are released by human activity, including methane and nitrous oxide. Methane is considered the second-most potent contributor to global warming. It increased 158 percent since 1750, from 700 parts per billion to 1808 ppb in 2010. Nitrous oxide increased 20 percent over the same period, from 270 ppb to 323.2 ppb.
“The three primary greenhouse gases are not only closely linked to anthropogenic activities, but they also have strong interactions with the biosphere and the oceans,” the report said. WMO Deputy Secretary-General Jeremiah Lengoasa said in an interview with the Associated Press that although human emissions of greenhouse gases are directly related to increasing temperatures, there is a time lag between the two. “With this picture in mind, even if emissions were stopped overnight globally, the atmospheric concentrations would continue for decades because of the long lifetime of these greenhouse gases in the atmosphere,” he said.
The WMO report comes on the heels of a summary report on risk assessment issued Nov. 18 by the Intergovernmental Panel on Climate Change, which warned that, under the groups “high emissions scenario,” the frequency of hot days will increase by a factor of 10 in most regions of the world.
“Likewise, heavy precipitation will occur more often, and the wind speed of tropical cyclones will increase while their number will likely remain constant or decrease,” said Thomas Stocker, Co-chair of Working Group I in the summary.
Another paper released in the Nov. 24 issue of the journal Nature provided the first evidence that the duration and magnitude of the current decline in Arctic sea ice seemed to be unprecedented for the past 1,450 years. Previously, the extent of ice loss was only known for last four to five decades, and questions remained about how much loss was due to natural variability. The researchers used land-based core samples to develop climate proxies so they could estimate the extent of the ice over a much longer period. The results suggest that Arctic ice loss is indeed being driven by manmade warming.
It remains to be seen whether the slew of new studies will make a difference in the stalled international negotiations to develop a comprehensive strategy to replace the Kyoto Protocol, which expires next year. Governments began meeting for the seven¬teenth meeting of the United Nations Framework Convention on Climate Change last Tuesday in Durban, South Africa.
Countries met in Copenhagen in 2009 and again in 2010 in Cancún, Mexico to hammer out a new agreement, but made little progress toward a comprehensive treaty anything like Kyoto. The U.S., by far the highest per-capita emitter in the world, was the only nation out of 192 members never to ratify the treaty.
