Cutting human sources of methane would reduce global warming and improve human health - scientists

Cutting human sources of methane would be a quick win for the climate, according to a new United Nations report.

Roughly halving emissions of the greenhouse gas from human activity, often with existing, cost-effective solutions, would reduce the future rise in global temperatures by around 0.3C by the 2040s, it is claimed.

The analysis was carried out by the UN Environment Programme and the Climate and Clean Air Coalition (CCAC).

Scientists have hailed the strategy as a "win-win" because it would reduce global warming and simultaneously improve human health and the economy.

Levels of methane in the atmosphere have doubled since pre-industrial times.

It is a potent greenhouse gas that is 10 times more powerful than carbon dioxide at trapping heat in the atmosphere.

According to the UN's Global Methane Assessment, human activity results in around 380 million tonnes of methane being released into the atmosphere every year.

Agriculture accounts for 40% of the emissions, largely from livestock and rice cultivation, while another 32% comes from oil and gas extraction and coal mining.

The report says reducing the emissions by 45%, or 180 million tonnes a year, by 2030 is critical for limiting global heating to 1.5C, the point where the climate would become increasingly and significantly unstable.

Professor Drew Shindell, chair of the CCAC and one of the report authors, told Sky News: "It's vital to tackle methane because it's the strongest lever we have to reduce the rate of warming in the near term.

"And that warming rate is what's leading to stronger hurricanes, more intense heatwaves, flooding, droughts all those consequences.

"Three tenths of a degree accounts for 70 billion lost hours of labour.

"That's people working outside in places that can't be air conditioned like agriculture and construction, so they are real costs to the economy, human wellbeing and more people dying from heat exposure.

"All these 10ths of a degree sound minor, but they're not at all."

The report says the target could be achieved with known solutions, many of which would pay for themselves within a few years.

They include reducing methane leaks from gas pipelines, better management of coal mines, eliminating organic waste from landfill and reducing meat consumption.

Reducing emissions would have a swift impact on global warming because the gas only survives in the atmosphere for around 10 years, whereas carbon dioxide stays there for several centuries.

Professor Grant Allen, professor of atmospheric physics at the University of Manchester, said: "This does not mean that cutting methane emissions alone can solve the warming problem.

"We must also continue to reduce carbon dioxide emissions to meet Paris Agreement targets and avoid dangerous warming.

"But it does mean that we can help to quickly slow the rate of global temperature increase and avoid some significant degree of warming in the near future."

As well as warming the climate, methane results in increased ozone air pollution.

Meeting the 45% target for reduced emissions would prevent 255,000 premature deaths and 775,000 asthma-related hospital visits every year, the report concludes.

Professor Dave Reay, executive director of the Edinburgh Climate Change Institute, University of Edinburgh, said: "Seldom in the world of climate change action is there a solution so stuffed with win-wins.

"This blunt report makes clear that slashing emissions of methane - a powerful but short-lived greenhouse gas - will deliver large and rapid benefits for the climate, air quality, human health, agriculture, and the economy too.

"Meeting the Paris Climate Goals will need every climate action trick in the book. Cutting methane emissions should be on page 1."

Sky News has launched the first daily prime time news show dedicated to climate change.

The Daily Climate Show is broadcast at 6.30pm and 9.30pm Monday to Friday on Sky News, the Sky News website and app, on YouTube and Twitter.

Hosted by Anna Jones, it will follow Sky News correspondents as they investigate how global warming is changing our landscape and how we all live our lives.

The show will also highlight solutions to the crisis and show how small changes can make a big difference.