Oceans are Absorbing Three Times Less CO2 than 20 Years Ago

By November 25, 2009 February 24th, 2013 CO2

This is some serious news. The study revised work that was done 20 years ago that showed the lag between atmospheric CO2 concentrations and global temperature. The previous study showed that there was a five month lag between CO2 concentrations and temperature. This new study has concluded that this lag has tripled from five months to fifteen months. What this means is that the oceans are absorbing CO2 three times more slowly today than they did twenty years ago.

AA quote from Physorg.com’s interview with the author, Jeffrey Park at Yale University, is revealing.

"No one had updated the analysis from 20 years ago," Park said. "I expected to find some change in the lag time, but the shift was surprisingly large. This is a big change.

The reasons why this change has occurred are still a bit unclear, but a warmer ocean definitely creates an ocean that has less capacity to absorb CO2, and our oceans today are at all time record temperatures (here). But it is likely that this is not the only reason. Changes in what the author calls "ocean dynamics" which are basically the way water circulates in the oceans are also implicated.  The dynamics in this case are the circulation that takes surface waters with more CO2 and sinks them,  so that they are replaced by deeper water that has lost some of its CO2 load due to normal ocean carbon sequestration processes.  When this circulation slows, the ability of the ocean to absorb CO2 slows because water with less CO2 in it can absorb more CO2 faster than if it is saturated or near saturation.

Another quote from the Physorg.com interview give us a stark warning of what has only previously been projected to happen in the future:

"Researchers have used climate models that suggest the oceans have been absorbing less CO2, but this is the first study to quantify the change directly using observations," Park said. "It strengthens the projection that the oceans will not absorb as much of our future CO2 emissions, and that the pace of future climate change will quicken."

Park, A re-evaluation of the coherence between global-average atmospheric CO2 and temperatures at interannual time scales, Geophysical Research Letters, November 2009