The WMO found that there was the biggest year-on-year jump in methane concentrations in 2020 and 2021 since systematic measurements began almost 40 years ago. Methane levels have risen rapidly in recent years, worrying scientists. Some have blamed this on the rise of fracking in the US, but this has been called into question as industrial emissions have not seen a similarly sharp rise. graphic 1 Now the theory is that the rise in methane could be caused by the activities of microbes in wetlands, rice paddies and the guts of ruminants. Rising temperatures have created ideal conditions for microbial methane production, as they enjoy warm, humid areas. Carbon dioxide levels are also on the rise, with the jump from 2020 to 2021 larger than the annual growth rate of the past decade. Measurements from WMO Global Atmosphere Monitoring Network stations show that these levels continue to rise. graphic 2 These greenhouse gases cause global warming, with warming increasing by 50% between 1990 and 2021. Carbon dioxide accounted for about 80% of this increase. According to the WMO, carbon dioxide concentrations in 2021 were 415.7 parts per million, methane was 1908 parts per billion (ppb) and nitrous oxide was 334.5 ppb. These are respectively 149%, 262% and 124% of pre-industrial levels. graphic 3 WMO Secretary-General Professor Petteri Taalas said: “The continued increase in concentrations of the main heat-trapping gases, including a record acceleration in methane levels, shows that we are heading in the wrong direction.” The most important stories on the planet. Get all the week’s environmental news – the good, the bad and the must-haves Privacy Notice: Newsletters may contain information about charities, online advertising and content sponsored by external parties. For more information, see our Privacy Policy. We use Google reCaptcha to protect our website and Google’s Privacy Policy and Terms of Service apply. Although alarming, the increase in methane was reversible and carbon dioxide remained the biggest threat, he added. “There are cost-effective strategies available to address methane emissions, especially from the fossil fuel sector, and we should implement them without delay,” Taalas said. “However, methane has a relatively short lifetime of less than 10 years, so its effect on the climate is reversible. “As a most urgent priority, we must curb carbon dioxide emissions, which are the main driver of climate change and associated extreme weather, and which will affect the climate for thousands of years through loss of polar ice, warming oceans and of sea level rise”. However, Taalas said time was running out to address the climate emergency as greenhouse gas concentrations in the atmosphere continued to reach new peaks. “We need to transform our industrial, energy and transportation systems and our entire way of life. The necessary changes are affordable and technically feasible. Time is running out,” he said. These figures will be presented at the UN climate conference Cop27 in November, where world leaders will gather in Egypt to hammer out agreements to reduce greenhouse gas emissions. However, even if they act quickly to stop the damage, much of it is already baked. As long as emissions continue, the global temperature will continue to rise. Given the long lifetime of CO2, the level of temperature observed will remain for decades, even if emissions are rapidly reduced to net zero.
