https://unfccc.int/news/new-methane-signs-underline-urgency-to-reverse-emissions
see also
https://climate.nasa.gov/news/2785/unexpected-future-boost-of-methane-possible-from-arctic-permafrost/ (2018-8-20)
https://www.theguardian.com/environment/2019/feb/17/methane-levels-sharp-rise-threaten-paris-climate-agreement (2019-2-17)
