Post by Roger Clifton on Dec 8, 2015 10:39:14 GMT 9.5
Well, it's official. The global mean CO2 concentration has broken through the 400 ppm mark, December 2015. The graph below shows the relentless rising trend that bodes little hope for stabilisation at 2° of warming.
Post by Roger Clifton on Feb 16, 2017 16:44:50 GMT 9.5
The seasonally corrected, rate of rise global atmospheric CO2 level has jumped up, measuring 3.61 ppm/a (Jan-Jan at Mauna Loa). At least, it has jumped up relative to a much lower rate of rise across the previous few years - the line drawn through the previous years on the figure below has a slope of 2.22 ppm/a.
Scientists who monitor the various tipping points around the world are no doubt carefully checking their data in case the surge is the start of each's own nightmare taking off. However before concluding that anything threatening at all has emerged, the reader should also consider that the constancy of the (usually accelerating) rate of increase over the previous few years has also been remarkable, and bound to break upwards eventually.
For explanation of the surge, attention will swing towards the oceanographers, who are able to make quantitative predictions of changes in CO2 emission and absorption by the changing surfaces (eg), upwellings and subductions around the continents.
The change at Mauna Loa between January 2016 in January 2017 was 3.61 ppm. However this very large value I would expect to average downwards again somewhat in the coming year. NOAA calculates the global rate of change in 2015 and 2016 as 2.98 and 3.36 ppm/a respectively. Nevertheless, the long-term curve of the CO2 concentration is relentlessly concave upwards. We must expect it to steepen across the years ahead, with the implied equilibrium temperature accelerating with it.
More tangibly, 3 ppm/a represents an extra 47 grams of CO2 each year, above every square metre of the Earth's surface, including the square metre that includes you right now. Saying "50 grams" may not mean much to your listeners, but it's more than a mole. You can also say, "above every square metre more than 20 litres of oxygen were replaced by CO2 last year", while showing a 20 mm gap between two fingers. It's an evocative gesture, internationally language-free and poster-ready.