Greenhouse gas levels surge despite slow economy

Australian sheep fitted with equipment to measure how much methane they breathe out. Image: By CSIRO, via Wikimedia Commons

The global economy has been hard hit by the Covid pandemic. But greenhouse gas levels have worryingly shot upwards.

LONDON, 13 April, 2021 – It’s a set of statistics likely to send shivers down the spine of any climate scientist – or everyone concerned about the future of the planet. Despite a slowing world economy due to pandemic shutdowns and other Covid-related factors, climate-changing greenhouse gas levels in the atmosphere surged last year.

The US government’s National Oceanic and Atmospheric Administration (NOAA), one of the world’s leading scientific institutions, says the global rate of increase in CO2 (carbon dioxide) levels in 2020 was the fifth highest on record. If there had been no economic slowdown, NOAA says, the increase in CO2 levels last year would have been the highest since records began.

“Human activity is driving climate change”, says Colm Sweeney, assistant deputy director of NOAA’s global monitoring laboratory. “If we want to mitigate the worst impacts, it’s going to take a deliberate focus on reducing fossil fuel emissions to near zero – and even then we’ll need to look for ways to further remove greenhouse gases from the atmosphere.”

Levels of CO2 in the atmosphere are measured on a parts per million (ppm) basis. Based on measurements gathered at various monitoring stations around the world, NOAA calculates that CO2 levels increased by 2.6 ppm in 2020 to 412.5 ppm, an increase of 12% since 2000 and a concentration level believed to have last been present during the mid-Pliocene Warm Period around 3.6 million years ago.

Methane prompts concern

At that time global sea levels were more than 20 metres higher than they are today, and vast forests are believed to have covered many Arctic regions.

Of even more concern than the surge in CO2 is a jump in levels of methane (CH4) in the atmosphere last year.

Methane is generated from various sources besides fossil fuels, including decaying organic matter, rice paddies, livestock farming and landfill sites.

The worldwide fracking industry is also a significant source of methane emissions. The gas is not as longlived in the atmosphere as CO2, but it is more than 30 times as potent.

“Human activity is driving climate change. If we want to mitigate the worst impacts, it’s going to take a deliberate focus on reducing fossil fuel emissions to near zero”

NOAA says atmospheric concentrations of methane increased last year by the largest level since records began nearly 40 years ago. Scientists have described this jump as surprising – and disturbing.

“It is very scary indeed”, Euan Nisbet, professor of earth sciences at Royal Holloway University in the UK told the Financial Times.

NOAA says the recent increase in methane levels is likely to have more to do with biological sources such as wetlands and livestock than with emissions from fossil fuels.

One theory is that, as temperatures rise and rainfall increases in many tropical regions, more methane is released from wetlands, crops and vegetation: a climate change “tipping point” is reached, as one warming event encourages and reinforces another.

Gas plumes detected

A new generation of highly sophisticated satellites is able to target with ever-increasing accuracy separate incidents of methane escape around the world.

In recent days unusually large releases of methane – known as plumes – have been recorded over Bangladesh, a densely populated low-lying country among those most at risk from changes in climate. The Bangladesh government says the plumes are likely sourced from rice paddies, rubbish dumps and landfill sites.

Earlier this year satellites monitored large amounts of methane escaping from gas pipelines in Turkmenistan in central Asia. Similar plumes were detected over the country last year.

In May 2020 a massive methane plume was detected by satellite over Florida. Investigations are ongoing, but it is thought to have come from the state’s gas pipeline system. – Climate News Network