Climate Change Bulletin 2016 #2: CO2

The initial estimate for the 2015 yearly increase in CO2 as measured from Mauna Loa, Hawaii, is now available.  It set a new record for amount of increase:  3.17 ppm.  This was the first increase above 3, and was 0.25 above the second biggest increase (1998). It also represented the first time the increase had surpassed 2 in either three or four consecutive years.  Increases in 1959-1964 averaged about 0.6 ppm per year, so that in the last 50 years the yearly increase has more than quintupled – a doubling approximately every 20 years. 

Projecting forward 40 years, the increase in 2055 would therefore be in the area of 12 ppm, and the total carbon in the atmosphere would be in the 600 ppm range, or more than double the pre-industrial value.  Projecting forward another 40 years, the yearly increase would be in the area of 45 ppm, and the total carbon ppm in the atmosphere would be about 1040 ppm, or four times the preindustrial value.  Acorrding to the estimate of James Hansen et al that each doubling of CO2 in the atmosphere historically corresponds in the long run to a 4 degrees C (7.2 degrees F) increase in global land temperature, and twice that in the far north/south, We are therefore talking about an increase of 8 degrees C or 15 degrees F from 1850 to 2100 "baked in" (that is, not achieved in 2100 but very likely to be reached 100-200 years later) on average and 16 degrees C or 29 degrees F in the far north/south. 

Already 1/2 of arable land has been lost to soil erosion, according to a recent study.  1/3 of the remaining land would be under threat from rising salt-water seas and storm surges due to the increased heat, by some estimates as high as 30 feet of seal-level rise by the end of the century.  Much of the rest would be under threat from massive droughts affecting all of the US except New England/NY/PA, most of Europe, much of the Middle East, India, most of Africa, Australia, and most of China.

That is all.