Climate Muscle Memory Gym - March 2020

Temperature records show March cooling slightly from the worrying highs of Dec-Feb, with the clearest fall showing in satellite records of atmospheric temperatures. Still, to my eyeball, this doesn't look to have cancelled the accelerating heating seen since early 2019.

• The Goddard surface temperature cooled 0.16c from Feb's spike;
• The land & ocean measurement came down only 0.06cs from Feb's high;
• The satellite reading of the troposphere came down 0.28c from Feb's spike high, to the lowest since Oct 2019.

As for greenhouse gas emissions, the Covid-19 shutdown in economic activity will not (yet) have an impact detectable beyond the range of natural variations in measurements. That said, March's rise in CO2 concentrations to 414.5 ppm was 1SD below the trend-rise. Don't get excited, because the trend itself is still accelerating mildly. Still, the 12m yoy is only 0.7% yoy.

The trend rises for the other main greenhouse gases (methane, nitrous dioxide and the horrible sulphur hexaflouride) are all now measurably slowing. Dec's (latest available) rise in concentrations for methane were 2SDs below trend; nitrous oxide was 1.1SDs below trend; and sulphur hexaflouride was 1.7SDs below trend. In fact, the world may be getting somewhere with sulphur hexaflouride (trace gas only, 10.09 pp trillion - but very powerful greenhouse effect), since the 12m growth rate of 3.5% is the slowest on record, and by Dec it had fallen to 3.2%.