Reacción a "Reactions to the detection of record methane concentrations in the atmosphere"

In numbers, this record methane emission is important because methane has increased by about a factor of 2.5 since pre-industrial levels. Its concentration stabilised during the first half of the 2000s and has continued to grow since then (about 63 ppb in the period 2011-2019). In the last three years its growth has accelerated despite the pandemic.

In terms of environmental impact, it is important because the increase in methane leads to increases in tropospheric O3, which is relevant for pollution and health, and in stratospheric water vapour, which also influences the radiative balance.

Methane emissions contribute to global warming. The contribution of methane to the atmosphere is smaller than that of CO₂, but its relative effect per unit is larger (one tonne of methane is equivalent to almost 30 tonnes of CO₂ in its radiative effect). It has no immediate short-term implications but is relevant to the achievement of net zero emissions targets by the middle of this century.

Rising CH₄ levels contribute to global warming and must be taken into account in emission reduction strategies. It does not facilitate them because part of methane emissions are of natural, not anthropogenic, origin.

The causes of this recent acceleration in concentrations are undoubtedly due to an increase in emissions. The specific origins of these emissions are under study. However, several natural and anthropogenic factors contribute. Temperatures in the Arctic and precipitation in the tropics contribute to inter-annual variations with emissions from wetland areas where decomposing material is present. The most likely causes of growth in the last decade are agriculture and livestock, which have seen increases in emissions in the last decade, as well as oil and natural gas production, including losses from leaking pipelines in the transport of oil and natural gas.