Despite two decades of talking about slowing global warming the actual rate at which heat-trapping carbon dioxide is building up in the atmosphere is accelerating according to new data released yesterday. Juliet Eilperin's story on this research made page 2 of the Washington Post and focused on the rapid increase in carbon dioxide emissions from fossil fuel combustion during this decade. These data are indeed alarming. They show that CO2 emissions from fossil fuel combustion and deforestation have now reached 10 billion tons per year, which is above the worst-case forecast made by the Intergovernmental Panel on Climate Change a few years ago.

But these emissions could be cut if governments, particularly in the U.S. and China, get serious about global warming action, rather than just talk. Even more disturbing are the data showing that the natural ocean sink for CO2 is slowing down, which we can't do anything about. Details are provided in an excellent presentation that Pep Canadell gave at an AMS briefing on Capitol Hill yesterday. The slowdown is due to rising ocean temperatures and falling ocean pH, both of which impede the ability of the ocean to absorb more CO2. The bottom line is that with emissions rising and removals declining the average annual increase in the amount of carbon dioxide in the atmosphere has jumped from 1.5 parts per million per year (ppm/yr) during the 1990s to 2.0 ppm/yr since 2000. The increase last year was 2.2 ppm.

These numbers are important because they are a direct measure of how rapidly the blanket of heat-trapping gases is thickening. While there is substantial uncertainty about deforestation rates and the size of the natural sinks, and some uncertainty about fossil fuel emissions, we can measure the concentration of carbon dioxide in the atmosphere with great accuracy. And the atmosphere doesn't lie.