Climate Sensitivity

Greenhouse Gas Concentrations in the Atmosphere Reach New Record


Global Warming?
Image191: Dreamstime

That's the headline on the World Meteorological Organization's press release for its latest Greenhouse Gas Bulletin report issued just before the 19th Conference of the Parties (COP-19) of the U.N. Framework Convention on Climate Change convenes later this month in Warsaw. The release notes:

The amount of greenhouse gases in the atmosphere reached a new record high in 2012, continuing an upward and accelerating trend which is driving climate change and will shape the future of our planet for hundreds and thousands of years.

The World Meteorological Organization's annual Greenhouse Gas Bulletin shows that between 1990 and 2012 there was a 32% increase in radiative forcing – the warming effect on our climate – because of carbon dioxide (CO2) and other heat-trapping long-lived gases such as methane and nitrous oxide.

Carbon dioxide, mainly from fossil fuel-related emissions, accounted for 80% of this increase. The atmospheric increase of CO2 from 2011 to 2012 was higher than its average growth rate over the past ten years, according to the Greenhouse Gas Bulletin.

Since the start of the industrial era in 1750, the global average concentration of CO2 in the atmosphere has increased by 41%, methane by 160% and nitrous oxide by 20%. What is happening in the atmosphere is one part of a much wider picture. Only about half of the CO2 emitted by human activities remains in the atmosphere, with the rest being absorbed in the biosphere and in the oceans.

Interestingly, the GHG Bulletin notes that the amount of greenhouse gases in the atmosphere has increased by 32 percent since 1990. Yet global average temperatures have been more or less flat for the last 15 years. Curious.

Heads up: I will be writing daily dispatches from the COP-19 in Warsaw from November 18 to its end on November 22.