Greenhouse gases continue to rise, says NOAA

Posted by Kate Taylor

The NOAA's latest Annual Greenhouse Gas Index (AGGI) shows that the presence of gases such as carbon dioxide and methane has risen by 29 percent since 1990.

Last year, the figure reached 1.29, compared with 1.27 the year before.

"The increasing amounts of long-lived greenhouse gases in our atmosphere indicate that climate change is an issue society will be dealing with for a long time," says  Jim Butler, director of the Global Monitoring Division of NOAA's Earth System Research Laboratory.

"Climate warming has the potential to affect most aspects of society, including water supplies, agriculture, ecosystems and economies. NOAA will continue to monitor these gases into the future to further understand the impacts on our planet."

The AGGI includes methane and nitrous oxide, as well as several chemicals known to deplete Earth's protective ozone layer.

The team found a continued steady increase in carbon dioxide, with the figure hitting 389 parts per million in 2010, compared with 386 ppm in 2009, and 354 in the index or comparison year of 1990.

 Before the Industrial Revolution of the 1880s, carbon dioxide concentration in the atmosphere was about 280 ppm.

Meanwhile, methane levels rose in 2010 for the fourth year running, after remaining nearly constant for the preceding 10 years. It's now up to 1799 parts per billion. The steady increase in nitrous oxide also continued.

: Best known as laughing gas in dentistry, nitrous oxide is also a greenhouse gas emitted from natural sources and as a byproduct of agricultural fertilization, livestock manure, sewage treatment and some industrial processes.

There was good news, though, for the ozone layer, with ozone-depleting chlorofluorocarbons CFC11 and CFC12 continuing to decline by about one percent per year since the late 1990s, thanks to the Montreal Protocol.