Reducing the role of methane in bringing about climate change


Connected Energy Solutions spoke with Mike Hemsley, head of analysis at the Energy Transition Commission, to find out how methane emissions can be reduced over the next decade to tackle their impact on global warming. 

When people talk about greenhouse gas emissions, a lot of people think about CO2 as a primary cause for concern. But methane has actually got quite a big impact in terms of the effects we can measure from GHG emissions. Can you talk us through that a little bit to start with? 

Sure. So, CO2 lasts for hundreds of years in the atmosphere, whereas methane actually has a much shorter atmospheric lifespan of just over 10 years. But, during the time that it is in the atmosphere, it is a much more potent greenhouse gas than CO2. Often that is measured in terms of global warming potential, which is the multiplier effect of how many CO2 molecules might methane represent in the atmosphere. 

The way you measure that depends on the timeframe that you measure it over, and obviously, because of its shorter atmospheric lifespan, the longer the time frame you were to measure it over, the less impactful methane is. In the short term, however, methane has a very large impact, potentially as much as 80 times as potent as CO2 over a 20-year timescale.  

Of course, there is a different order of magnitude when it comes to the volume of different GHG emissions. We produce something like 40 gigatonnes of CO2 per year – 40,000 million tonnes – whereas we produce only 400 million tonnes of methane. Even so, the Internation Panel on Climate Change (IPCC) estimates that, of the warming that has occurred to date – roughly 1.1 degrees overall – 0.45 degrees are a result of methane emissions, which is quite striking and makes you question why we have not focused on them much so far. 

Which sectors produce the most methane, and is there any correlation between those producing large amounts of CO2? 

Around 40 per cent of methane is produced in the agricultural sector, mostly from ruminant animals such as cows. So, meat or dairy products are associated with methane emissions, but generally, those products are not associated with CO2 emissions directly. Another 20 per cent of methane emissions come from rotting waste – farm waste, human waste, etcetera – and that also does not produce much CO2 unless it is burned off. 

The other 40 per cent of methane emissions come from extracting fossil fuels, which obviously has a much more direct link between methane and CO2 

Businesses adopt various methods of carbon accounting throughout their supply chains to track CO2 emissions via Scope 1, 2, and 3. Is there an equivalent measurement to track methane emissions?  

No, not really, that would be a bit more difficult to do for a couple of reasons. Firstly, CO2 emissions are easier to track because, with methane, you would need to trace back to where a fossil fuel originally came from, or the emissions associated with each and every food product people at your company consume. So, in terms of the amount of data you would need, it is much more difficult, and on top of that, the measurement system for methane emissions is much less precise. 

Some companies do have emissions reduction targets that include all GHGs though, including methane. 

How can the agriculture and waste sectors reduce methane emissions? 

The main thing is to look at each sector individually and try to understand how to reduce emissions within them because obviously, the solutions will not all be the same. 

In terms of agricultural methane, most of that is produced by the animals when they are fed as part of their digestive process. There are some techniques that reduce the amount of methane they produce, for example, feeding cows seaweed is estimated to produce less methane overall compared to traditionally grass-fed cows. So, you could in theory switch cattle diets to seaweed, but there will still be some methane produced. The biggest lever we have is encouraging people to eat less meat, rather than some kind of technological fix, in order to reduce emissions. 

Waste management, I guess, is similar to some extent. For example, landfills produce methane as things decompose within them, and you can see it rising from them. You can trap that methane and convert it into energy we can use, which reduces the amount of methane leaking into the atmosphere. But another level there is also just reducing the amount of waste we produce which occurs through supply chains and logistics, particularly in the food and agricultural sectors. 

And what about in the fossil fuels industry? 

It depends on whether it is oil, gas, or coal. With oil and gas, methane leaks as part of the extraction process. Some of it is flared off to reduce the pressure in the extraction system, but instead of flaring it, you could capture it and use it. There is already an economic incentive to do that because you could just sell that gas instead of burning it. When organisations such as the International Energy Agency look at this stuff, they produce charts that show where methane emissions come from and how much of it can be reduced at a negative cost, because you can just sell that fossil fuel instead. So, that is the big target in those industries, and most countries are now starting to move towards this. In the US, for example, the oil and gas industries are lagging behind in terms of dealing with methane leaks, and they have ramped up pressure to try and rectify this by signing the global methane pledge to reduce methane emissions. 

With coal extraction, my understanding is that it is quite a bit more difficult, to the extent that there is not a lot that can be done about how methane is produced while the mine is open. Once that coal mine is decommissioned though, it can be flooded or blocked to stop methane from escaping into the atmosphere. 

Is capturing methane, similarly to carbon capture and storage (CCS) for CO2, a realistic option? 

The simple answer is no. There are some very early studies that are considering it, but it is definitely not viewed as simple or as mature a technology as CCS. 

So, would you say that similarly to CO2 emission, one of the most effective ways to reduce methane emissions would be to transition to renewable energy sources? 

I think so yes, certainly in the long run, and that is something we definitely think is possible. The ETC scenario for 2050 envisions reducing oil usage by 90 per cent, and gas by 60 per cent, with coal being almost completely eliminated from the energy mix. 

There are things that can be done during this transitory phase though which are particularly important over the next decade. Norway is a great example of a country that has put in place strict regulations that have led to very low methane emissions associated with oil and gas extraction. In most countries, it is about the kinds of political pressures there are, and the will to get it done, and that will be very important if we want to avoid the worst consequences of climate change. 

I suppose this question loops back to the beginning, in a way. But, why do you think reducing methane does not seem as big a part of the conversation surrounding GHG emissions? 

Part of it is just due to the overall volume of the gas. But I think people are becoming increasingly worried about methane because of its potency; it still has an almost proportionate impact compared to CO2 on a near-term warming basis. 

Another part is probably uncertainty over the overall emissions estimates. We have been tracking CO2 for a long time, but where methane emissions are concerned, there is still a wide range of estimates across industries. It is much more difficult to estimate how much methane a cow emits compared to how much CO2 is emitted by a power station, for example. 

Finally, I think the actions to reduce methane emissions are much more difficult to communicate. Politically, it is difficult to ask people to change their diet, even if it is possible to show that if most people’s diet is aligned to what is seen as healthy eating guidance anyway, that would have a significant impact on methane emissions. Paying to install a wind farm is a lot simpler than convincing people to eat less beef. 

Could you give me an overview of the opportunities for methane emissions reductions you highlighted in the recent ETC ‘Keeping 1.5°C alive’ report? 

Sure. So, in that report, we highlighted opportunities to reduce methane emissions by around 40 per cent by 2030, which is seen as an essential part of meeting the world’s 1.5°C warming objectives overall. In line with the IPCC, what we wanted to particularly highlight were the massive opportunities to reduce methane emissions in the oil and gas sector, noting countries that have the biggest impact. So, the United States, Russia, Iran, Iraq, etcetera.  

We think methane emissions reductions of that order of magnitude are possible this decade, and we think that the global methane pledge is a really good start for getting these big actors involved in reducing that overall. 

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