https://www.scientificamerican.com/article/methane-is-on-an-alarming-upward-trend/ > Cows, oil and gas wells, rice paddies, landfills. These are some of the biggest sources of methane staining the atmosphere today. Methane is the most important greenhouse gas after carbon dioxide, and its concentration reached a record 1,875 parts per billion (ppb) last year, more than two and a half times preindustrial levels. Peak methane in the atmosphere feels as elusive as a cure for the (next) coronavirus.
 > As scientists at the Global Carbon Project, we and dozens of our colleagues just published a four-year study and public data sets of the Global Methane Budget to estimate methane sources from land, oceans, agriculture and fossil fuel use. Methane emissions reached a record 596 million metric tons per year (range of 572–614 million tons including error estimates) in 2017, the last year for which data are fully available. We present the results in the journals Earth System Science Data and Environmental Research Letters.