Posted by Pete McBreen 09 Jan 2010 at 18:39
Since the trends on global CO2 levels are not good, I decided that it would be useful to watch how they are changing, The historical trend has been that on average we are increasing CO2 levels by approx. 1.9ppm/year. Based on this trend we will probably reach 400ppm in April or May 2015.
But we will see fluctuations up and down over the course of the year
This is a feature of the way the climate relates to the overall earth systems, the CO2 level drops as vegetation grows in the northern hemisphere summer, and then rises during the northern hemisphere winter, peaking in the spring, and then starting to fall off again in June. On an annual basis this fluctuation is around 6 ppm, but year on year we are averaging nearly 2ppm higher - but this varies with the economy and the weather in any year, hot years tend to be associated with a higher rise.
Below is sample data extracted from CO2Now.org which is also the source of the badge.
Overall this is a large scale experiment
How much CO2 can humans add to the atmosphere without adversely affecting the climate systems that we depend on?