Photo: Yaorusheng / Getty Images.
The importance of methane has been underestimated and overshadowed by the urgent need to reduce carbon dioxide emissions. Climate actions to reduce methane are often included as ‘CO2 equivalents’ in national climate plans, like in commitments made by countries in the Paris Climate Agreement. But the impact of methane and carbon dioxide are not equivalent. While the focus to reduce climate change has rightly been placed on carbon dioxide, methane is the second most important greenhouse gas that has given rise to the warming experienced to date, and is also a major precursor of ground-level ozone formation, a pollutant that negatively impacts health and crop yields.
The atmospheric concentration of methane is increasing faster now than at any time since the 1980s, with more than 50% of global methane emissions stemming from human activities in the fossil fuel, waste and agriculture sectors. Compared to carbon dioxide, methane however is relatively short-lived in the atmosphere, with a lifetime of about 12 years. This means that taking action now can quickly reduce methane concentrations, resulting in a similarly rapid reduction in warming of the climate.
By using five state-of-the-art modelling tools, the new Global Methane Assessment identifies important opportunities to reduce the rate of global warming and achieve significant health and development benefits by specifically reducing methane emissions from human sources.
The conclusion? Now is the time for methane reduction to be a high priority. Here are three reasons why.
1. Reducing methane now will avoid nearly 0.3oC of warming by 2045
More than half of global methane emissions arise from human activities and 95% of these emissions come from three sectors:
- 35% from fossil fuels (23% from oil and gas, and 12% from coal)
- 20% from waste (including the waste sector, landfills and waste water)
- 40% from agriculture (32% from livestock, and 8% from rice cultivation)
The implementation of methane reduction measures on human sources of methane now could reduce methane emissions by as much as 45% by 2030. According to the Assessment, this would avoid nearly 0.3oC of warming after 2040, contributing significantly to keeping the 1.5oC Paris Agreement target within reach. To limit warming to 1.5oC at the lowest cost, methane emissions need to be reduced across the three main emitting sectors by 2030 as follows:
Reduction in methane emissions required per sector, as a percentage of total sector methane emissions.
2. Reducing methane now will protect human health and crop yields
As methane not only warms the atmosphere as a greenhouse gas, but is also a major precursor in the formation of ground-level ozone, there are significant additional health, economic and development benefits from acting on methane now.
A 45% reduction in human-caused methane emissions by 2030 equates to a reduction of 180 million tonnes of methane emissions per year. This would vastly reduce the formation of and exposure to ground-level ozone. Each year after 2040, this would globally prevent:
- 255 000 premature deaths
- 775 000 asthma-related hospital visits
- 26 million tonnes of crop losses globally, and
- 73 billion hours of lost labour from extreme heat.
Ground-level ozone is the most potent air pollutant affecting crop yields and forest productivity, by suppressing plant growth and yield. Reducing methane to reduce ozone concentrations could avoid the loss of a combined 26 million tonnes of wheat, maize, soybeans and rice each year. This is roughly 1-2% of the global yield of these four staple crops in 2020. Given the increasing global population, and demand for food and land to produce it, this benefit is also highly significant.
Photo: John P Kelly / Getty Images.
3. Reducing methane now is cost-effective and the tools are readily available
Reducing human-caused methane emissions is one of the most cost-effective strategies to rapidly reduce the rate of warming and contribute significantly to global efforts to limit temperature rise to 1.5oC. Implementing already known methane reduction measures in the fossil fuel, waste and agriculture sectors are cost-effective and can be implemented quickly. Implementing existing measures in these sectors would reduce methane emissions by 120 million tonnes per year, making up nearly 70% of the total 180 million tonnes per year reduction required by 2030, to avoid 0.3oC warming by 2045.
*Mt/yr = million tonnes per year
Around 35% of this 180 million tonnes per year reduction comes from implementing existing measures in fossil fuel management:
- oil and gas sector: 29–57 Mt/yr*
e.g. recovery and utilization of vented gas, improved control of unintended emissions from the production of oil and natural gas
- coal sector: 12–25 Mt/yr
e.g. pre-mining degasification, flooding abandoned coal mines
Around 18% of the reduction comes from implementing existing measures in waste:
- waste sector: 29– 36 Mt/yr
e.g. in solid waste management: no organic waste in landfill, source separation with recycling/reuse; in wastewater treatment: upgrade to two-stage treatment with biogas recovery
Around 17% of the reduction comes from implementing existing measures in agriculture:
- rice: 6–9 Mt/yr
e.g. intermittent flooding and draining, direct wet seeding, use of hybrid species
- livestock: 4– 42 Mt/yr
e.g. feed changes and supplements, selective breeding to improve productivity and animal health/fertility.
Around 30% of the reduction comes from implementing additional measures not focused primarily on methane:
60 million tonnes per year up to 2030 are assumed to come from measures related to:
- energy
e.g. implementing renewable energy for power generation, improved energy efficiency
- waste
e.g. reduced food waste, reduce food loss and waste
- healthy diets
e.g. reduced consumption of red meat and dairy
Roughly 60% of readily available reduction measures that need to be implemented to achieve the 45% reduction by 2030 have low or ‘negative’ costs. 82 million tonnes of methane emissions per year could be reduced by low-cost measures (at a cost of less than US$600 per tonne). ‘Negative’ cost measures (measures that pay for themselves over their lifetime) can reduce emissions by about 40 million tonnes of methane per year. Most of these ‘negative cost’ measures are in the oil and gas industry.
- 60-80% of oil and gas measures could be implemented at negative or low cost
- 55-98% of coal measures could be implemented at negative or low cost
- 30-60% of waste measures could be implemented at negative or low cost
Case study 1: Cote d’Ivoire
SEI and others engaged in the Climate and Clean Air Coalition’s SNAP initiative have been supporting countries to develop their methane reduction scenarios. At the national scale, by working with practitioners from environment ministries or universities, it is possible to understand how national development plans will affect methane emissions in the future. One example of this is from working with the Ministry of Environment in Cote d’Ivoire. Rice is an important staple crop and at the moment a significant amount is imported. The plan is to satisfy future demand for rice through national production in paddy fields. This will increase methane emissions, but if this expansion is done by using intermittent flooding and draining techniques, the increase in methane emissions can be controlled. If applied to existing rice growing, it can lead to a net reduction in methane emissions from this source in Cote d’Ivoire.
Case study 2: Bangladesh
In Bangladesh, SEI has supported the development of an officially endorsed National Action Plan for reducing short-lived climate pollutants (like methane). The Plan identified five priority measures to reduce methane, which included:
- bringing 20% of irrigated land under intermittent flooding and draining techniques by 2030, and 100% of irrigated land by 2040;
- reducing emissions from livestock by 25% through manure management and biogas development;
- reducing methane from wastewater by improving the management of human waste;
- reducing methane from ruminant animals by changing diets; and
- reducing methane from municipal waste, by diverting and composting organic matter, and using landfill gas to produce electricity.
Where do we go from here?
The drive for decarbonization to cut global greenhouse emissions is critical, and as we move away from fossil fuels, we will inevitably reduce methane emissions too. But decarbonization alone will not be able to reduce methane emissions to the extent we need. We must also put methane at the forefront of climate action this decade.
By starting now, over the next decade, we have a huge opportunity to help limit global warming to 1.5°C above pre-industrial levels and reduce health and crop impacts from ozone, through targeted and rapid reductions in methane emissions. If this is to become reality, we need to establish the goal of reducing methane emissions by 45% by 2030, as the scientific benchmark for policymaking on methane regulation.
To solve the climate change crisis we need to change – pretending otherwise is unhelpful. This means changing our energy system away from fossil fuels and reducing leakages while we still use them. But it also means changing our food and waste systems, agricultural practices and diets. We can reach the 2030 goal by switching to healthier diets with less red meat and dairy, as long as we also deal effectively with food waste and other sectors. So, we can be healthier, reduce waste and help prevent excessive climate change – what’s not to like?
