EVERY year human endeavours emit 50bn tonnes of “carbon dioxide equivalent”. This way of measuring things reflects the climatic importance of CO2, which traps heat in the atmosphere for centuries before it breaks down, compared with other, shorter-lived greenhouse gases.
Of that 50bn-tonne total, 70% is carbon dioxide itself. Half the remaining 15bn tonnes is methane. In the past decade methane levels have shot up (see chart), to the extent that the atmosphere contains two-and-a-half times as much of the gas as it did before the Industrial Revolution. Earlier this month America’s National Oceanic and Atmospheric Administration (NOAA) confirmed another sharp rise in 2017.
This is disturbing for two reasons. First, methane is a powerful heat-trapper. Although it is far less abundant than carbon dioxide and stays in the air for only a decade or so, molecule for molecule its warming effect (calculated over 100 years) is 25 times higher. Keeping methane in check is therefore critical if a rise in temperature this century is to remain “well below” 2°C relative to pre-industrial times, a goal set out in the Paris climate agreement of 2015. The second concern is that methane’s latest rise is poorly understood. The explanations put forward by scientists range from the troubling to the truly hair-raising. More research is needed to determine the correct degree of anxiety.
Atmospheric methane is biological in origin—but some of the biology happened a long time ago. The bulk of this ancient methane gets into the atmosphere during the production and transport of natural gas, of which methane is the principal component. A lesser amount leaks straight out of the ground. But this fossil methane is only 20% of the total. The remaining 80% is produced by micro-organisms which break down organic matter. These so-called methanogens inhabit soils, preferably moist ones, as well as the digestive tracts of ruminants (and, to a lesser extent, other animals, humans included).
https://www.economist.com/science-a...xplain-a-worrying-rise-in-atmospheric-methane
Of that 50bn-tonne total, 70% is carbon dioxide itself. Half the remaining 15bn tonnes is methane. In the past decade methane levels have shot up (see chart), to the extent that the atmosphere contains two-and-a-half times as much of the gas as it did before the Industrial Revolution. Earlier this month America’s National Oceanic and Atmospheric Administration (NOAA) confirmed another sharp rise in 2017.
This is disturbing for two reasons. First, methane is a powerful heat-trapper. Although it is far less abundant than carbon dioxide and stays in the air for only a decade or so, molecule for molecule its warming effect (calculated over 100 years) is 25 times higher. Keeping methane in check is therefore critical if a rise in temperature this century is to remain “well below” 2°C relative to pre-industrial times, a goal set out in the Paris climate agreement of 2015. The second concern is that methane’s latest rise is poorly understood. The explanations put forward by scientists range from the troubling to the truly hair-raising. More research is needed to determine the correct degree of anxiety.
Atmospheric methane is biological in origin—but some of the biology happened a long time ago. The bulk of this ancient methane gets into the atmosphere during the production and transport of natural gas, of which methane is the principal component. A lesser amount leaks straight out of the ground. But this fossil methane is only 20% of the total. The remaining 80% is produced by micro-organisms which break down organic matter. These so-called methanogens inhabit soils, preferably moist ones, as well as the digestive tracts of ruminants (and, to a lesser extent, other animals, humans included).
https://www.economist.com/science-a...xplain-a-worrying-rise-in-atmospheric-methane
