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Methane crucial for limiting climate change to 1.5 degrees

A University of Reading study has shown just how crucial reducing methane emissions will be to achieving the Paris Agreement target of limiting global temperature rise to 1.5^oC.

Researchers found reducing methane emissions would help reduce global warming between now and 2100, therefore allowing up to 900 billion tonnes more carbon dioxide CO₂ emissions in the same period.

Compared to no methane reduction, this would more than double the amount of CO₂ permitted in order to hit the 2015 Paris target of limiting global temperature rise to 1.5^oC above pre-industrial levels, and add 50% more than that permissible to not exceed a 2^oC rise.

The research was led by Professor Bill Collins, Professor of Climate Sciences at the University of Reading, and published in Environmental Research Letters.

Professor Collins said: “A dramatic and immediate reduction to methane emissions would have a significant impact on reducing global warming, but even a smaller reduction would make hitting the Paris targets more realistic by giving us some leeway on CO₂ emission cuts.

“The study shows the rewards on offer to the world if greenhouse emissions are better managed to avoid dangerous climate change.”

The researchers examined three hypothetical scenarios, where carbon budgets allow global temperature to stabilise at 1.5^oC (with and without initial overshoot) and 2^oC above pre-industrial levels by 2100.

Previous Reading research has shown, while much less abundant, methane is 32 times more potent as a greenhouse gas than carbon dioxide.

Non-climate benefits from reducing methane emissions include better air quality and vegetation productivity, as well as reducing deaths worldwide by around 130,000.

The study was one of three recently co-authored by Professor Collins and fellow Reading scientist Dr Chris Webber.

A Nature Geoscience paper revealed global fossil fuel emissions would have to be cut by as much as 20% more than previously estimated to achieve the Paris Agreement targets, because of natural greenhouse gas emissions from wetlands and permafrost. Read the Centre for Ecology and Hydrology news story.

A further Nature Communications study published this week showed replacing forests with crops for bioenergy power stations that capture carbon dioxide (CO₂) could actually increase the amount of CO₂ in the atmosphere. The researchers found preserving and enhancing forests was a more sensible option in many places. Read the University of Exeter news story.