Methane reaches record values in the atmosphere for the second consecutive year

Recorded carbon dioxide levels also continue to rise at historically high rates, according to the National Oceanic and Atmospheric Administration (NOAA). Both gases are primarily responsible for global warming.

Unless action is taken on the activities that drive it, this type of record will be the norm year after year: for the second consecutive year, atmospheric methane levels reached a record amount in 2021, according to data from the National Oceanic and Atmospheric Administration (NOAA), a leading agency of the United States Government in the monitoring of greenhouse gases.

Preliminary analysis shows that the annual increase in atmospheric methane over the past year was 17 parts per trillion (ppb), the highest figure since measurements began in 1983. In 2020, despite the pandemic, the rise was 15.3 ppb. Atmospheric methane levels averaged 1,895.7 ppb during 2021, which is 162% higher than pre-industrial levels. It is also estimated that global methane emissions last year will be 15% higher than in the period 1984-2006.

Methane is usually in the shadow of carbon dioxide (_CO2), the main gas that warms the planet. However, CH4 (the formula by which this hydrocarbon is known) is responsible for about half of the 1.2 °C increase in the global average temperature since the pre-industrial era. Its warming potential is more than 80 and 28 times that of carbon dioxide over a horizon of 20 and 100 years, respectively.

In addition, its life in the atmosphere is shorter – between 9 and 12 years – than that of CO₂, so if its emissions were reduced, effects on temperatures would be noticed more quickly. The IPCC report, published this week, made it clear that without reductions on this gas it would be impossible to mitigate climate change. According to the panel of specialists, to limit the temperature by 1.5 ºC it is necessary to reduce methane emissions by 34% by 2030. Doing so would prevent heating of up to 0.3 °C.

This figure is in line with the proposal that was born at COP26. During the last climate summit in Glasgow, a hundred countries signed the Global Methane Commitment, an initiative promoted by the United States and the European Union with the aim of reducing methane emissions by 30% by 2030.

However, in order to achieve this goal, there will need to be no gap between actual emissions and country-reported emissions. In February this year, the International Energy Agency (IEA) reported that methane emissions linked to the oil, gas and coal sectors rose by 5% in 2021 and are much higher than those officially reported by governments to the UN. The mismatch is not small: there is a 70% difference.

Where does methane come from and how to reduce it?

Of the total methane emissions worldwide, 60% come from anthropogenic sources, that is, they are the responsibility of humans and their activities. Of this percentage, more than 90% originates in only three sectors: fossil fuels (35%, although these emissions have been “seriously underestimated” according to a study last year), agriculture (40%) and waste (20%). Livestock is responsible for almost a third of methane emissions. 92% is attributed to ruminants, which expel these gases mostly through belching and respiration. The remaining 8% comes from non-ruminants, such as chickens and pigs.

A report published last year by UN Environment noted that if technical measures already available were adopted, anthropogenic methane emissions could be reduced by around 20% per year on their own. That percentage, they argue, could rise to at least 45% with broader structural and behavioral measures.

In the UN Global Methane Assessment, also presented in 2021, they pointed out that behavioral changes, such as dietary modification or the fight against food waste, could contribute up to 44.4% of annual emission reductions (65-80 million tons per year), while technical innovations in agriculture, like animal feed supplements, they could contribute up to 16.7% at a rate of about 30 million tonnes per year by 2030. This assessment, however, established a more ambitious reduction than that of the IPCC: 45% by the end of the decade, which translates into 180 million tons less of this gas per year.

Undertaking these changes and lowering CH4 emission levels would avoid, according to United Nations estimates, some 260,000 premature deaths, 775,000 asthma-related hospital visits, 73 billion hours of work lost to extreme heat and 25 million tons of crop losses per year.

CO2 _{also goes up}

Carbon dioxide levels recorded by NOAA also continue to rise at historically high rates comparable to the Pliocene epoch, about 4.3 million years ago. The global average of_CO2 on the surface during 2021 was 414.7 parts per million (ppm), representing an increase of 2.66 ppm over the 2020 average. It means it’s the tenth year in a row that this gas has increased by more than 2 parts per million, representing the fastest sustained rate of increase in the 63 years since its monitoring began. It is estimated that the safe level of_CO2 in the atmosphere is 350 ppm, a value that was exceeded in the 90s.

Over the past year, 36 billion tons of carbon dioxide were emitted into the atmosphere from human activity. For comparison: that same year, methane emissions were about 640 million tons. Unlike methane,_CO2 remains for thousands of years in the atmosphere. What is emitted today will continue to warm the planet for generations: “The effect of carbon dioxide emissions is cumulative. About 40% of the emissions of the 1911 Ford Model T are still up in the air today. We are halfway to doubling the abundance of carbon dioxide that was in the atmosphere at the beginning of the Industrial Revolution,” said Pieter Tans, senior scientist at NOAA’s Global Monitoring Laboratory.

Source: Climate