It has been suggested that high-latitude methane emissions from terrestrial environments could have enhanced a period of global warming about 55 million years ago. A decrease in the carbon isotope values of hopanoids (a biomarker derived from bacteria) at the onset of the warm period is reported, which suggests an increase in methanotroph populations . This could reflect an increase in methane production and release from the terrestrial biosphere, which could have acted as a positive feedback mechanism in global warming.
- Richard D. Pancost
- David S. Steart
- Ian J. Glasspool
