Methane (Environment and Climate Change Committee Report)

Lord Trees Excerpts

Tuesday 13th May 2025 Grand Committee

[Lord Trees (CB)]

My Lords, it is a pleasure to be a member of this Select Committee and to speak here today. I thank our chair and our excellent staff who support our committee; they really have been outstanding. I have no major interests to declare except that I am a veterinarian and a co-chair of the All-Party Parliamentary Group for Animal Welfare. I have no financial interests of relevance.

I will concentrate on the contribution of UK agriculture, and specifically ruminants, to methane emissions, because they are such a significant part of our total anthropogenic methane emissions. We have already heard that methane is an extremely potent greenhouse gas, but it is short lived: it remains in the atmosphere for about 12 years, compared with CO₂, which remains for hundreds if not thousands of years. This is critically important: constant emissions of CO₂ accumulate and increase global warming, whereas constant emissions of methane stabilise at equilibrium after a few years and warming stabilises. Crucially, reducing methane emissions results in cooling, so major global reductions in methane emissions provide a unique opportunity to slow the pace of global warming in the short term, while CO₂ reduction and removal technologies can be further developed.

Globally, methane emissions are rising, which is very disturbing. However, I am pleased to say that in the UK our methane emissions are not rising; in fact, there has been a significant reduction of over 60% since 1990. However, reduction within agriculture has been relatively small. Agriculture is now responsible for approximately 50% of the UK’s anthropogenic methane emissions, virtually all of which is from ruminants, particularly cattle.

Different metrics are significant in understanding the impact of methane and formulating policy. Internationally, the metric GWP100 is used to quantify the global warming potential of different greenhouse gases over 100 years within different sectors. However, it can misrepresent methane’s warming impact by not considering its short-lived nature in the atmosphere. In a nutshell, GWP100 overestimates the impact of constant methane emissions by threefold to fourfold, underestimates the impact of newly emitted methane by fourfold to fivefold and fails to account for the cooling effects when methane emissions reduce.

To address these limitations, scientists, in particular at the University of Oxford, have developed GWP*, which better accounts for the short-lived nature of methane in the atmosphere. Experts differ on the pros and cons of GWP100 and GWP*, but comparisons emphasise how significantly the way in which data are analysed and presented can influence policy and priorities. For example, the emissions warming potential of a unit of beef estimated using GWP100 is three and a half times greater than when utilising GWP*. For this reason, our report recommends that

“the Government should … consider how additional metrics can be robustly employed at the sectoral and the business level to improve understanding of the UK’s emissions”

and

“move towards unilaterally implementing an auxiliary metric to better reflect the warming impact of methane”.

However, in their response to our report, the Government remained unconvinced on fully supporting the use of GWP* to assess agricultural emissions, which I regret; I think that it has a role to play in understanding the problem we have.

A second metric of importance is methane intensity—that is, the amount of methane or its CO₂ equivalent per unit of productivity. Data based on FAO figures show that, for example, a kilogram of protein can be produced from cattle in the UK at a quarter of the CO₂ equivalent emissions of the global average. In general, although our beef and dairy industries are significant emitters of methane, they are lesser emitters compared with other countries from which we may import beef and dairy products. The issue of importation is particularly relevant in relation to the recent US-UK trade agreement, for example, and other agreements to be negotiated; our Select Committee report makes these important points very clearly.

I turn to mitigation, where there is good news. There is a lot more that we can do in the UK to further reduce methane emissions from our ruminants. We have some of the world’s best experts in methane monitoring and abatement, as we have heard, and we have highly innovative and progressive farmers. However, as our report highlights, the Government have a role in setting this as a priority for agricultural support. It is regrettable that the sustainable farming incentive has been paused, especially since the Agriculture Act 2020 explicitly provided that, in the transition from the CAP, the Secretary of State could support climate change mitigation measures.

This is not just about finance, although that is important. Much could be achieved by the Government setting clearer goals, providing consistent advice and technical support, and encouraging peer-to-peer knowledge transfer to address methane emissions and to ensure that all of our farmers are adequately equipped with both knowledge and a desire to something about it. In their response, the Government acknowledged that there may be benefits to a targeted approach for agriculture to better incentivise methane reductions; we look forward to seeing evidence for this. Most measures to increase productivity will reduce emissions per unit of production. Improved health and disease control, smarter management such as reducing calving intervals, nutritional measures and breeding for reduced methane emissions—methane output is a heritable trait—are all achievable means that increase profitability and productivity, as well as reducing methane emissions per unit of production.

With reference to breeding, new genetic technologies, as provided for in the Genetic Technology (Precision Breeding) Act 2023, could rapidly advance progress. As was referred to earlier, feed additives such as Bovaer show promise. This product has recently been approved for use in the UK by the Food Standards Agency, and I note that some governments in Europe already subsidise farmer application of this product.

The Dairy Demonstrator project—now branded as the UK Dairy Carbon Network and launched in February by the current Government—will include support for participating farms to investigate and trial various emission mitigation methods. It is to be welcomed; I congratulate the Government on that.

Substantial improvements in endemic disease control —for example, better application of current vaccines—are technically possible now that we have the necessary products to improve emission intensity. The introduction by the previous Government of the animal health and welfare pathway is to be welcomed; it can make a positive difference.

Impacts on slurry and manure cannot be ignored as they are responsible for about 7% of the total anthropogenic methane emissions and affect all livestock species. A number of abatement technologies are applicable, including covering slurry tanks and anaerobic digestion of the waste. Given that farms are often small or medium enterprises, major capital improvements require co-operation among farmers—and, probably, some financial support—but those investments could yield significant benefits in reducing methane release.

In conclusion, in the UK, ruminants fed mainly on grass in one form or another produce healthy and nutritious food but also about half of all of the UK’s anthropogenic methane emissions. However, the estimate of the warming potential of these emissions varies by more than threefold depending on which metric is used. Moreover, current data show that greenhouse gas emissions per unit of production for both beef and dairy are substantially lower in the UK than most other countries. However, there is much that we could and should still do to reduce our methane emission intensity. In many cases, the technology exists but there needs to be consideration of cost-benefit ratios to achieve full implementation.

The bottom line is that we must guard against destroying our own livestock industry, which is relatively environmentally efficient, and the inevitable consequence: importing more meat and dairy produced with poorer environmental efficiency and greater emissions elsewhere.