Big news on CO2 trends this morning from the Honolulu papers: atmospheric measurements taken at the Mauna Loa Observatory show the rate of increase in carbon dioxide has been increasing exponentially since 2005 (via Star Bulletin).
John Barnes, who runs the MLO, reports faster growth ever since atmospheric carbon dioxide hit 380 parts per million in 2005.
Bear in mind that the Stern Review focused on 450 ppm as the threshold above which dramatic climate changes are likely to occur, and that the long term trend shows CO2 increasing at 2.5 ppm.
Do the math. Time is running out faster now.
OK, so the news is better on ozone-depleting chemicals, which Barnes notes has stopped increasing since the Montreal Protocol was signed 20 years ago.
Earth has lost probably about 6 percent of the ozone layer that protects the planet from harmful ultraviolet radiation, Barnes said. "In 20 years it should start to reverse and come back."
Better still, this ozone improvement has probably cut in half the amount of greenhouse warming that would have occurred by 2010 unabated.
Says Barnes, "The amount of warming that was avoided is equivalent to seven to 12 years of rise in carbon-dioxide concentrations in the atmosphere".
The National Oceanic and Atmospheric Administration's 11,140-foot observatory on Mauna Loa has the longest continuous measurements of atmospheric CO2 in the world.
Other greenhouse gases measured are methane and nitrous oxide and ozone-depleting gases such as chlorofluorocarbon and CFC-12. Methane levels have stayed about the same, and chlorofluorocarbon gases have been declining in recent years, according to observatory records.
During 800,000 years of history recorded in ice cores, including big ice ages every 100,000 years, carbon dioxide cycled from 180 to 280 parts per million molecules of air, Barnes said.
That changed around 2005, says Barnes. "The de-seasonalized, postindustrial trend in added carbon dioxide has been increasing exponentially, with a doubling time of about 32 years".
Ho hum, right?!