Statistics from the International Energy Agency show how over a 20-year period, methane has more than eighty times the warming power of carbon dioxide. However if the world could collectively bring methane emissions down to 65% of what they are today, then by 2030 there is a chance of meeting the Paris Agreement target of global warming increasing by just 1.5 degrees Celsius above pre-industrial levels.
The Global Methane Budget 2024 paints a troubling picture of the current state of global methane emissions. The new report reveals that human activities are now responsible for at least two-thirds of world-wide emissions of the gas. This marks a significant increase in human-produced methane sources – rising 20% over the past two decades, with the fastest increase over the last five years.
Reaching Net Zero
Leaked methane does warm up the ozone layer more quickly than carbon dioxide. On the positive side, methane’s atmospheric lifetime is 10–12 years which compares better than carbon in the atmosphere, which will be present for a hundred years or more. Methane’s shorter lifespan means that if levels of methane are brought down, then the resultant percentage in the air is reduced quickly, and so too, its harmful warming effect.
Anthropogenic Methane Emissions
Methane naturally occurs – for example, leaking from wet peatlands and ground newly exposed by melting ice fields but emissions from sources controlled by humans is an equal contributor to greenhouse gas totals.
Anthropogenic methane emissions are increasing every year and with rising populations, extended manufacturing and the general requirement for power on an upward trend, these levels of methane emissions seem set to rise further. The need to seriously explore cutting this gas is a global concern, and below is an exploration of some of the ways being tested and adopted.
Coal, Oil and Gas
In 2022, The Oil and Gas Climate Initiative (OGCI, a group of 12 of the world’s leading oil and gas companies) launched the Aiming for Zero Methane Emissions Initiative, a call for the industry to treat methane emissions as seriously as it was already treating safety. Four main sources of methane emissions from the oil and gas industry are identified by the OGCI, these are incomplete combustion from burning pits, gathering pipeline emissions, equipment venting and storage tank venting.
There is now a satellite in place constantly monitoring methane in the atmosphere which has enabled leaks or poor practice to be pin-pointed around the world. So far, OGCI has worked with ‘operators of assets in Algeria, Kazakhstan and Egypt’ and, by improving their working methods, has helped ‘eliminate methane plumes in Algeria and Kazakhstan with a combined average rate of 3,200 kilograms an hour’ estimated to be equivalent to 1 Mt CO2 in one year.
‘Over 40% of oil and gas emissions could be reduced at no net cost using well-known existing technologies’, including leak detection and repair campaigns, installing emissions control devices, and replacing components and devices that emit methane in their normal operations.
Avoiding methane emissions from coal is considered harder to achieve. A priority is switching from coal to an appropriate replacement fuel to reduce coal consumption. In an International Energy Agency (IEA)’s forecast, ‘Net Zero Emissions by 2050 Scenario’, coal use needs to drop this decade by 55% and it needs to fall by almost 90% by 2050.
Capturing methane prior to a coal mine starting production, as well as when they are already in operation, is happening. One example is trapping methane from the air ventilating the mine then using the gas as an energy source, perhaps to heat mine facilities or for coal drying. These technologies are however, far from standard industry practice and there needs to be ways to broaden their use through creating incentives or direct mandates requiring mine operators to adopt these technologies.
Rice Growing
It is calculated that 8% of agricultural methane emissions are created by the traditional way rice is grown, and particularly the common practice of leaving the paddy fields flooded between each three-yields-a-year crop. This is done mainly to supress weed growth but as the spent crop rots in the water, the anaerobic decomposition gives off methane.
There are projects researching a new drier method of cultivation, which encourages draining the fields between crops. This system reduces the amount of methane produced by between 30% and 50% and it has the added environmental benefit of reducing the water that’s used to between 10% and 20% without affecting the rice yield.
Research is ongoing into methods to deal with rice stubble too, for every ton of rice produced, a ton of straw is left behind after harvesting. In some instances, the waste straw is burned but ploughing it back into the ground instead reduces greenhouse gas emissions significantly. This mulch adds nutrients into the soil too. The problem here is the lack of machines to do this. Another option being looked at is using the stubble to make paper or medium density fibre board (MDF), again there are problems to overcome such as transport to mills but there is investment being made into these solutions and research and testing is ongoing.
Beef and dairy
Cattle get a bad press as far as methane production and emission goes but the proportion of global emission attributable their breath, manure etc., is far less than rice growing.
The projects to reduce methane from cattle range from feeding seaweed supplements, which has been shown to change the way their traditional diet is digested in their stomachs so less methane is produced, to gene selection – identifying individual ruminants to find ones whose enteric stomach fermentation produces less than average amounts methane – the idea being that these lower-methane-emitting animals are the ones chosen for future generations to be bred from.
Other agri-methane projects use captured ammonia and methane from sealing slurry pits with a waterproof covering. The cover has two benefits, allowing the gas capture from the slurry and also providing a barrier to prevent rainwater entering the pit, causing overflow leaks. The captured methane can be used as a fuel for combustion engines.
The future
There are many solutions in development, being tried and tested to reduce methane emissions in all sorts of ways around the world. With a new focus on the shorter term advantages of reducing methane to reach net zero targets, the future looks hopeful.