“AD technologies are readily available, low-cost, and well positioned to achieve global scale to deliver immediate and cost-effective action on climate change,” writes Drew Shindell, lead author on the UNEP/CCAC global methane assessment report and Climate and Clean Air Coalition Special Representative for Methane Action & Nicholas Distinguished Professor of Earth Science, Duke University.
The world must act now to rapidly reduce emissions of methane and other greenhouse gases or risk putting the global 1.5°C target out of reach. Human-caused methane emissions are growing at an alarming rate, with atmospheric concentrations increasing faster now than at any time since the 1980s. Data from the United States National Oceanic and Atmospheric Administration shows that despite an overall drop in air pollution and a slowdown in CO2 emissions caused by COVID-19 lockdowns, methane emissions spiked in 2020.
While methane has both human and natural sources, the recent increase is driven primarily by human activities. These come from three sectors: fossil fuels (35 per cent), waste (20 per cent), and agriculture (40 per cent).
In May 2021, the UN Environment Programme and the Climate and Clean Air Coalition published a Global Methane Assessment which, for the first time, comprehensively integrates the climate and air pollution costs and benefits from methane mitigation. According to the Assessment, human-caused methane emissions must be reduced by approximately 45 per cent by 2030 to limit global temperature rise to 1.5°C this century.
Methane is a powerful short-lived climate pollutant which drives climate change and harms human and ecosystem health by contributing to the formation of ground-level ozone. In part because of its link to air pollution, there are significant health, economic, and development benefits from reducing methane emissions. A 45 per cent reduction would prevent 260,000 premature deaths, 755,000 asthma-related hospital visits, 73 billion hours of lost labour from extreme heat, and 26 million tonnes of avoided crop loses annually. The benefits from avoided premature deaths alone are approximately USD $450 billion per year by 2030, far outweighing the costs of implementation.
Fortunately, there are readily available and cost-effective methane-targeted measures, in all major sectors, which can reduce 2030 emission levels by more than 30 per cent this decade. More than 80 per cent of these targeted measures have low mitigation costs, with approximately 40 per cent having negative costs, meaning that they can pay for themselves quickly by generating revenue.
The waste and agriculture sectors represent more than half of human-driven methane emissions. As part of a portfolio of actions, anaerobic digestion technologies can provide substantial, low-cost mitigation in these sectors this decade while simultaneously producing useful products such as biogas.
Using anaerobic digestion to turn organic food, farm and sewage waste into biogas and biofertiliser that can be sold or used on-site to generate energy, can help reduce methane and create a sustainable source of revenue and job creation. Furthermore, local to industrial scale anaerobic digestion technologies are well understood and have operated around the world for nearly half a century. These technologies are readily available, low-cost, and well positioned to achieve global scale to deliver immediate and cost-effective action on climate change.
Targeted measures alone will not be enough to put the world on a 1.5°C consistent pathway. Additional measures that do not specifically target methane, like a shift to renewable energy, residential and commercial energy efficiency, and a reduction in food loss and waste can reduce methane emissions by a further 15 per cent by 2030.
The conclusions and benefits of action are clear. Methane mitigation is one of the most significant climate actions the world can take this decade. There are cost-effective solutions that can be implemented immediately and the benefits far outweigh the costs. The world needs to make 2021 a ‘methane moment,’ by committing to implement policies and measures to rapidly reduce methane emissions and working to drive a decade of methane action.
Climate and Clean Air Coalition Special Representative for Methane Action & Nicholas Distinguished Professor of Earth Science, Duke University.