Atmospheric Carbon Watch #2

Last week I mentioned the Mauno Lao observatory monitoring carbon and other greenhouse gases. www.esrl.noaa.gov/gmd/ccgg/trends/#mlo.

I noted the upward trend is very pronounced and levels of CO2 are well beyond anything experienced in human evolutionary time.

Two further points I would like to make are that the record declines as often as it rises and that the rise in CO2 parts per million has a close correlation with emissions. This latter point may sound obvious but surprisingly few people seem to have taken the step of working out the connection between emissions and resultant CO2 ppm.

In terms of the first point – each northern hemisphere spring sees carbon pulled from the atmosphere at a truly global scale. The atmospheric CO2 ppm actually falls approximately 6 parts per million while the factories and automobiles etc continue to pour out pollutants. The fall/winter season sees CO2 ppm jump back up by approximately 8.5 ppm.

At risk of being repetitive the only mechanism on the planet capable of genuinely resolving this is the creation of healthy topsoil. That is long term locking up the carbon pulled out of the atmosphere by plants in spring. I do want to explore that concept in future blogs.

In this blog the focus is the curious correlation or ration occurring now between for example 2010 emission of approximately 25 Gigatons (billion tons) of Carbon Dioxide and an increase in atmospheric CO2 of approximately 2.5 parts per million.

This ratio is generally assumed to have been less directly correlated in the past however as the oceans have become saturated with CO2 it is assumed this impacted their ability to absorb atmospheric carbon. Currently oceanic Carbon is the largest single reservoir we know of. There is approximately 40,000 Gigatons Carbon in the salt waters of the earth. This is both a positive and a negative.

Positive because without the oceans absorbing CO2 from the first 200 years of the industrial age the atmospheric Co2 level would have reached a critical level long before anyone thought to monitor it.

Negative because the oceans actively exchange with the atmosphere so any reduction in atmospheric CO2 will draw more CO2 from the ocean until some time when the ocean’s vast volume of CO2 has been significantly reduced.

A correction to last weeks’ blog. I noted the earth could reach 400ppm CO2 by 2012. This is not correct. I mistakenly extrapolated from the peak reading rather than a seasonal mid point such as January. 2013 or 2014 are more likely candidates for the planet to exceed 400 ppm CO2.