Energy market volatility in recent times testifies to the pivotal role the natural gas market plays in today’s economic system. While the precise future path of the ongoing global energy transition is impossible to foresee, natural gas will play an important role in nearly all imaginable scenarios, at least for several decades. That creates significant environmental and sustainability challenges which need to be addressed.

Natural gas is composed mostly of methane (CH₄), together with smaller amounts of other gases. When burnt in power generation plants or used for heating, it releases carbon dioxide (CO₂). This is a main focus of climate policy, along with the adverse health effects of other gases emitted during the combustion of any fossil fuel.

However, an at-times overlooked issue is the direct leakage of CH₄ itself into the atmosphere. CH₄’s molecular structure implies it packs a heavy global warming punch. On a time-horizon of 20 years, each tonne of CH₄ escaping into the air traps an amount of heat over 80 times greater than the equivalent amount of CO₂. Even after 100 years, CH₄’s total captured heat is close to 30 times greater. Thus, any leakage is a serious issue for global warming.

There are natural flows of CH₄ into the atmosphere. For example, CH₄ is released by the anaerobic decomposition of plant and animal matter under water (sometimes called marsh gas). Wetlands are a major natural source of such CH₄. The escaping gas is subsequently broken down by so-called chemical ‘radicals’ in the air that create a natural ‘sink’. Overall, natural inflows and outflows broadly balance themselves, leaving a stable stock of CH₄ in the atmosphere. This forms an important part of the earth’s natural greenhouse effect, essential to our ‘Goldilocks’ planet - neither too hot nor too cold, just right to allow life to flourish (including us!).

However, the wake of CH₄ from direct human activities is also present in the atmosphere. The main sources today come from fossil-fuel extraction, storage, and transport, together with livestock farming practices and land-fill waste management. Moreover, there is a risk that rising global temperatures caused by human activity could spark a ‘tipping point’ with the escape of large amounts of methane from melting perma-frosts.

The stock of atmospheric CH₄ is growing, and is already responsible for over 25 per cent of the global warming that we are experiencing today, according to the United Nations Environmental Programme (UNEP)

Overall, because of the human factor, the rate of methane additions to the atmosphere is greater than the atmosphere can decompose naturally. As a result, the stock of atmospheric CH₄ is growing, and is already responsible for over 25 per cent of the global warming that we are experiencing today, according to the United Nations Environmental Programme (UNEP).

So, what can we do about it? There are two good news stories here. Firstly, because of its potency, any CH₄ reductions we can engineer offer rapid climate benefits. Secondly, reductions can be achieved not just quickly but at low cost, with the energy sector a key focus.

For context, if we could reduce the direct emissions of methane in the global oil & gas industry by 45%, it would achieve as much climate benefit in the next 20 years as closing 1,000 coal plants (UNEP). The International Energy Agency (IEA) estimates that these reductions can be achieved at net zero cost with existing technologies. Underlying this startling assertion is the fact that CH₄ emissions from the oil and gas value chain represent a wasted product with a value of over US$30bn per year.

So, in terms of quick wins for climate policy, the detection and the elimination of rogue methane emissions is as close to a ‘no brainer’ as we are likely to find in the fossil-fuel industry. Accurate and scalable detection technologies are advancing fast to help us. Some sensible policy incentives could create a positive tipping point to accelerate further innovation and implementation. The Global Methane Pledge at COP26 was a positive start (100 countries representing 70% of global GDP are committed to 30% CH₄ reductions by 2030), but pledges are not policy, as we know from the broader context of protecting the global environment.

There is one major rider to this comforting conclusion. Methane capture cannot be a substitute for CO₂ reduction – it can only be a complement. To explain this fully would take us into deeper environmental territory, but the simple story is this: while CH₄ packs a big ‘heat punch’, it is a relatively short-lived greenhouse gas before it starts to decompose in the atmosphere. CO₂ is much-longer lived and the total tonnage of it we pump into the atmosphere each year is well over 100 times greater.  As a result, the excess CO₂ emissions currently being emitted are creating practically irreversible changes to our atmosphere for many generations to come.

Invisible gases leave visible impacts, and they are not ones for which our descendants will thank us. We must do what we can – and tackling the methane threat is certainly not a bad place to start. As they say in Ireland, “Tús maith leath na hoibre” (a good start is half the work). Let’s get going – this bit is simple sustainability economics.