Why strong methane cuts are needed alongside CO2 net-zero to keep warming below 2°C

The useful part

Close View all View all View all Stay up to date Get the latest climate news direct to your inbox. Methane traps heat in the atmosphere more efficiently than CO2, but has a significantly shorter lifespan, fading after just a few decades. Therefore, reducing emissions of methane – a gas primarily produced by agriculture, fossil fuels and waste management – is a powerful option for limiting global warming in the near-term.

How it works

• We show that, even under the most ambitious existing national net-zero targets, an absence of methane reduction leads to peak warming that exceeds 1.85C above pre-industrial levels.
• The question is as difficult to answer as: 'how much spaghetti equals a chicken?' You could compare the two meals according to their calories, protein content or cost.
• As a result, our research looks at the necessary methane reductions for both types of goal.
• The figure below shows how peak warming depends on both the year of reaching net-zero CO2 and the level of methane cuts.
• The blue arrows in the figure show that to limit warming to 1.7C under a 2050 net-zero CO2 scenario, methane emissions would need to fall by at least 69% by 2050, relative to 2020.

What to take from it

But, because methane and CO2 have different atmospheric lifetimes and warming properties, any conversion is only valid for a chosen time horizon and a chosen baseline. Because they combine CO2 and methane emissions, the impact of methane emission cuts alone is difficult to isolate in existing emission scenarios. Yet climate strategies and models often only focus on CO2, or combine all greenhouse gases into one metric known as "CO2 equivalent".

Example or evidence

• Our research also finds that, if an organisation or country's 2050 net zero-target covers all greenhouse gases, its methane emissions would need to fall by 63% instead.
• In a new study, published in Communications Earth & Environment, we offer a different perspective that "decouples" CO2 and methane reduction and takes global warming limits as a starting point for...
• It hides the opportunities and challenges linked to methane's high warming and short lifetime.
• The study highlights that, to limit peak warming to well-below 2C, net-zero CO2 targets must be complemented by stringent methane emissions cuts.

Details worth keeping

Why tough methane cuts are crucial for keeping warming 'well-below' 2C. How much methane corresponds to one tonne of CO2? Each metric can be convenient, but is only valid for that specific comparison – no amount of spaghetti is the same as a chicken.

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