By Eszter Vlasits, Deputy Editor-in-Chief
An overlooked greenhouse gas
If somebody were to ask you right now to mention one of the greenhouse gases, my bet is that most of you would go for carbon-dioxide. CO2 has become the ‘face’ of harmful gas emissions, it is the one that is brought up the most and it is at the centre of most policy plans trying to aid the reduction of greenhouse gases in the atmosphere. However, while cutting back on CO2 is undeniably essential in the fight against global warming, one gas poses even more danger: methane. While its lifespan in the atmosphere is much shorter than that of CO2, the warming impact of a pound of methane is 25 times more powerful in terms of contribution to warming than the equivalent amount of CO2. It has such a high impact, that if humanity succeeds in reducing methane emissions by 45% during the next decade, we might be able to shave off as much as 0.3 degrees of warming in the next 2-3 decades (which is quite significant, keeping in mind the 1.5 0C goal). Let’s now take a look at what methane is and why is it dangerous, then explore the prospects of the ‘methane bomb’: large amounts of the gas being released as a consequence of climate change.
Methane, or CH4, is a gas naturally found in the environment, but human activities contribute to more than half of the amount emitted. Probably the most often mentioned source of methane is from raising livestock and agriculture. In these cases, it happens in different ways such as cows digesting their food via a process called enteric fermentation and then belching up the gas, or rice paddies being flooded and locked away from oxygen, which is an ideal environment for the formation of methane. A lot of methane also comes from landfills, where bacteria break down organic waste, releasing the gas in the process.
One third of human-caused methane emissions come from the fossil fuel industry, and this is where substantial reductions could take place. All throughout the supply chain, methane leaks everywhere from facilities and even from cargo ships. And although this can seem like another case of ‘illegal polluting activities of corporations’, these emissions are actually not illegal. A lot of times companies are not even aware of the methane leaks due to faulty equipment and lack of maintenance, and report emission levels much lower than reality. Experts estimate that fossil fuel companies could cut back on 75% of their methane emissions using already existing technologies.
The ‘sleeping danger‘
Next to these sources of methane emissions, there are large reserves locked away in the ground in the areas of the Northern hemisphere where permafrost is present. Permafrost is ground that stays continuously frozen for long periods of time, which can be situated not only under land, but also under the ocean. It can most commonly be found in Canada, Greenland, Siberia and under the ocean surrounding the Arctic, and it is estimated that it holds 60 billion tons of methane additional to the staggering 560 billion tons of organic carbon. The soil in these places contains the remains of plants and animals from the past several thousand years, as back then, when the Earth’s climate was vastly different from the current one, these areas had rich biodiversity. Because today the ground here is frozen all year round, they are not broken down, but instead stay intact, not releasing any harmful gases. However, when the frozen soil thaws, the resulting water pools in what are called thermokarst lakes. In the lakes and the thawed soil, similar to what happens in a landfill, microorganisms start breaking down and processing the organic materials, resulting in the release of a lot of methane. Thermokarst lakes are not merely the product of global warming, this process to a certain extent is natural and cyclical. However, the current circumstances are causing abrupt thawing and the accelerated forming of lakes, which results in increased methane emissions. As in the past decades, average temperatures all over the planet have been rising dramatically and in an accelerating manner, we can expect the permafrost to also thaw faster and faster in the coming years. And if that was not enough, we know that the Arctic is clearly warming more than twice as fast than the rest of the planet due to changes in albedo (the reflective ability of the surface).
Non-linear climate change
It is pretty obvious that if large amounts of methane get released via this process, the course of climate change will be visibly influenced: this is called a feedback mechanism. So what are climate feedbacks? As NASA describes, they are ‘processes that can either amplify or diminish the effects of climate forcings’: ‘Positive’ is the type feedback that increases initial warming, while negative feedback decreases it. For example, ice melting at the Arctic causes the albedo of the surface to change, which results in even faster melting, and a positive feedback loop. In the Earth system, there are countless processes like this, each one interacting with each other, and methane is one of the largest positive feedbacks with the highest potential to accelerate climate change.
Part of what predictions regarding climate change are often limited is that there are just too many factors playing together and influencing each other, resulting in a change that is not linear. The idea of non-linear climate change has been picked up lately in scientific literature, explaining how most predictions include events that are less dramatic but likely to happen, and leave out low-probability but high-consequence events. The possibility of such events happening is very hard to calculate, but it is certain that if they do happen, they will alter the course of climate change dramatically. One example is the circulation system in the North Atlantic Ocean collapsing, which plays a key role in regulating the climate on the entire hemisphere, and another one is what we are talking about here: the abrupt release of billions of tons of methane and carbon from the thawing permafrost. The main danger is that these possibilities, because they are ‘runaway’ events, are not included in climate change scenarios, since they would make accurate predictions almost impossible. This of course results in most people completely ignoring the issue, and some others treating it like the impending and unavoidable apocalypse.
Should we just add methane bomb to the list of possible catastrophic events that can happen in the future and seal our fate regarding climate change? Based on the geophysics of the process, experts say this ‘timebomb’ is not likely to blow, and if the thawing is regulated, a large part of the positive feedback can be avoided. There are so many aspects of climate change that seem like they don’t have feasible solutions and tackling them can be overwhelming. In contrast, methane emissions are something we not only know a lot about scientifically, but also have the tools to reduce them drastically and at a relatively low cost. Focusing on this issue on a policy level and successfully cutting back on methane would reduce the severity of the warming in the short run, giving us more time to come up with systemic solutions.
Cover image via pixabay