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Podcast November 17, 2021

Tell Me How: Will mitigating methane emissions cool the planet?

View all episodes on our Tell Me How: The Infrastructure Podcast Series homepage

In this episode we discuss the global warming impact of methane and several ways- some with zero net costs- in which this impact can be reduced.

This podcast series is produced by Fernando Di Laudo and Jonathan Davidar. 

Listen to this episode on your favorite platforms: Amazon MusicApple PodcastsGoogle PodcastsPodbean, and Spotify


Roumeen Islam: This is the World Bank’s Infrastructure podcast. In today's episode, we will be discussing how methane emissions affect global warming. 

Scientists are using increasingly better methods to understand how human activity is affecting our habitat. And we know more than we ever did before. Little did I know when I bought my house that the gas leaks, I was warned about were not only potentially dangerous for my immediate health but would one day cause concern regarding their effects on the planet. 

Neither did I realize how ubiquitous were leaks of a particular gas called methane, not only in the home and in wastewater, but all the way to coal mines, even abandoned ones. And just yesterday, I read about a coal mine project in Colorado, which captures methane from an abandoned coal mine to produce electricity with it. 

There are many ways in which we can reduce our methane emissions. So, let's find out how. 

Good morning and welcome. I am Roumeen Islam host of telling me how and my guest today is Ilissa Ocko, Senior Climate Scientist and Barbra Streisand Chair of Environmental Studies at the Environmental Defense Fund. She will be speaking to us today about a gas called methane. Welcome Ilissa. It's very nice to have you here. 

Ilissa Ocko: Hi, so happy to be here.  

Roumeen Islam: So, Ilissa, perhaps we could begin by explaining what methane is, where it comes from, and why it's important.  

Ilissa Ocko: Methane is a greenhouse gas that is the second largest contributor to the current climate crisis. It's responsible for at least a quarter of today's warming because human activities such as raising livestock, producing fossil fuels and managing waste have more than doubled the amount of methane found naturally in the atmosphere.  It's responsible for at least a quarter of today's warming because human activities such as raising livestock, producing fossil fuels and managing waste have more than doubled the amount of methane found naturally in the atmosphere.

Roumeen Islam: That I didn't know. That's a big increase. So, you say that methane is one of the most important anthropogenic, greenhouse gases. But its concentration is far below that of carbon dioxide, right? So, why do you think it deserves special attention in climate policymaking?  

Ilissa Ocko: Yeah, it's true that there is a lot less methane in the atmosphere than CO2 and that we emit a lot less methane from human actSecond, how much we emit into the atmosphere. And third, how long it lasts in the atmosphere. Methane is far more potent than CO2. So, even though we emit a lot less of it, a smaller amount of methane can cause more warming than a larger amount of CO2. 

To provide some quantification here. This is because methane's molecular structure is capable of absorbing more energy than CO2 and because methane forms other greenhouse gases in the atmosphere as well, most notably tropospheric ozone. 

Roumeen Islam: So sorry, just to interrupt you. CO2 is carbon dioxide. And when you say tropospheric ozone, what does that mean? 

Ilissa Ocko: So, there is the ozone that is formed in both the troposphere and the stratosphere. The troposphere is the layer of the atmosphere that is closest to the surface of the earth. This is the air that we breathe, this is the part of the atmosphere where our weather is. And so, when tropospheric ozone is formed or ozone is formed in the troposphere, it's very toxic to humans and plants.  

Roumeen Islam: Okay, thank you.  

Ilissa Ocko: So, because methane is so potent and we emit enough of it to cause more than a quarter of today's warming, our emissions are on pace to double by the end of the century, which could cause even more warming. 

So basically,  But beyond this, 

And this is because methane only lasts in the atmosphere for around a decade. So, when we cut methane emissions, we almost immediately reduce its warming impact. Just quickly, on the other hand, CO2 is a major concern because it can last for centuries in the atmosphere. So, even though it is less powerful at trapping heat than methane, our emissions of CO2 can commit us to warming for generations. 

And so, the bottom line here is that

Roumeen Islam: All right. So, before we go on, what do you mean by short lifetime in the atmosphere? 

Ilissa Ocko: Any pollutant that lasts around a decade or less in the atmosphere is considered short-lived. And this is because

Roumeen Islam: But what happens if we don't act right now, what'll happen? What are the implications of that for global warming?  

Ilissa Ocko: , even if we make drastic cuts in CO2 emissions.  Because we have the technologies and strategies available right now to cut global methane emissions from human activities in half. And if we pursue a rapid full-scale effort to deploy these solutions over the next decade, we could slow down the worldwide rate of warming by as much as 30 percent in the following decades. 

Roumeen Islam: That’s very important to know. And it's also important to know that you said that if we act quickly, we could curb the frequency of these extreme weather events, which are causing a lot of damage around the world.   

Now, has there been a fast increase in the rate of emissions, because you said that the concentration or the amount of methane in the atmosphere has increased a lot, but has it been increasing at a faster rate?  

Ilissa Ocko: So global methane emissions have risen by around 10 percent over the past two decades. 

And the amount of methane in the atmosphere has increased faster over the past decade than in the previous one. And last year's rise was actually the biggest increase. And so, part of this increase in the amount of methane in the atmosphere is from human sources, like increased natural gas production and rising meat consumption. 

But part of the rise in methane emissions, scientists think, is also from natural sources of methane, like wetlands that can emit more methane as temperatures increase. So, this is an increase in natural methane emissions, but it's in response to human caused climate change. So, it is in essence human caused as well. 

Roumeen Islam: You mean because we have essentially made the earth warmer and that's why there are more emissions. And that's why it's human caused. Is that what you are saying? 

Ilissa Ocko: Exactly. 

Roumeen Islam: So, why hasn't there been much of a focus on methane mitigation, given all these things that you just said? Because it would seem we should've started acting on this a while back.  

Ilissa Ocko: When governments first started considering how to address climate change back in the 1980s and 1990s, the impacts of climate change were a future concern. 

And because carbon dioxide is the number one pollutant that controls the extent of future climate change, it made sense that the primary focus was on CO2. And because action was hard enough if we only had limited resources to address climate change, anything other than actions to reduce CO2 was considered by some to be a distraction. 

Roumeen Islam: All right. So, I understand that focusing on carbon dioxide was considered difficult enough, given limited resources, but wasn't there at the same time, some effort on trying to estimate the impact of these other gases? 

Ilissa Ocko: Absolutely. There are a number of different pollutants that we emit into the atmosphere that can trap heat there. In fact, there are hundreds of them, and there are around a handful that we emit enough of and that are potent enough to certainly contribute to climate change, or at least have been a concern even back in the eighties and nineties.  

But another side effect of our focus on CO2 is that most people assess how non-CO2 pollutants contribute to climate change by comparing their impacts to that from CO2. 

And so, when you do this comparison and you're basically evaluating any non-CO2 pollutant by converting it into the amount of CO2 that would have the same impact, it requires a time horizon over which you're comparing the climate impacts.  

Because if you recall, the three factors that I mentioned earlier on that make a pollutant matter; potency, amount, and lifetime, we need to factor in the lifetime of these pollutants when assessing a climate pollutant warming impact. With our focus on climate impacts in the long-term, which again, made sense decades ago, the time horizon that was most commonly employed in these assessments and is carried on over time is assessing how these pollutants contribute to climate change over the following 100 years after they're admitted.  

Again, this made sense when climate change was mostly a future concern. But what it means is that we are overlooking the near-term potency of short-lived climate pollutants. Because what we are essentially evaluating is how a pulse of emissions of a non-CO2 pollutant impact the climate over the following 100 years. So, for short-lived pollutants, this means you are basically emitting a pulse of emissions right now, and then you are accounting for its impact on the climate over the next 100 years. 

But for the majority of that time period, that pollutant is no longer in the atmosphere, warming the earth, but the CO2 which lasts for a really long time would be. So, this accounting method has led to a complete undervaluing and unawareness of the power of methane in contributing to climate change over short time periods. 

And what that also means is that we've completely overlooked the power of its emissions reductions in curbing climate. 

Roumeen Islam: So, are you saying that we might “discover” that we've been overlooking other gases that we should have been curtailing? 

Ilissa Ocko: over the past decade, we've really ramped up our awareness of how all of these different climate pollutants impact climate change over different timescales. We're using better metrics and there are more scientists that are working on this challenge. 

So, it really is just methane that we've found to be undervalued in such a way that we could miss out on an opportunity to curb climate change. When you look at the climate pollutants we emit and how they contribute to today's climate change, CO2 is number one, it contributes around to around half of today's warming and methane is number two, it contributes to at least a quarter of today's warming. When you look at the climate pollutants we emit and how they contribute to today's climate change, CO2 is number one, it contributes around to around half of today's warming and methane is number two, it contributes to at least a quarter of today's warming.

Every other climate pollutant that we look at, contributes a lot less than all of those. 

Roumeen Islam: Okay. So, you're saying also that the thinking or the attention on this has changed because our knowledge of methane has grown and there are more people, policymakers, business leaders, paying attention to it. Is that right? 

Ilissa Ocko: Yeah, it's been a really exciting year for methane action. We refer to it often as the methane moment and part of the reason why methane is really on the radar right now is because climate change is no longer this future concern. It is a pervasive threat that we face on a daily basis. And we've seen remarkable progress on methane action this year in particular. 

We've seen attention to methane from the highest levels of government in several countries. 

Roumeen Islam: Very good. So, can we move on to which are the main sectors responsible for releasing anthropogenic methane?  

Ilissa Ocko:  And the common thread here is that methane is formed when microbes break down organic material in conditions that lack oxygen. 

So, this can occur deep, underground, underwater, and even in a cow's gut. So, for agriculture, there are two main sources, livestock, where methane is produced in the stomach of certain animals like cows, and then belched out, and methane is also formed in piles of manure from livestock. And secondly, rice production where methane is formed because the rice patties grow in flooded fields. 

For energy, the large majority of methane emissions come not from burning fossil fuels, which is the source of CO2, but from producing fossil fuels because natural gas, which is mostly methane, can easily leak into the atmosphere when extracting gas and oil and when mining for coal. So, some natural gas is even intentionally vented into the atmosphere. And a lot of natural gas can leak when it is transported and distributed to homes and buildings.  

So, over the last decade, we've learned a lot about how much methane is emitted from energy production and realize that it is far greater than what governments were reporting.  

And finally, for waste management, methane is formed in landfills and wastewater, as bacteria decompose food and yard waste in the landfills and organic matter that can be found in sludge in the wastewater. 

Roumeen Islam: So, it can be found in many places. So, my next question is what is the potential to mitigate in the areas you mentioned? What's the abatement potential. And could you talk a bit about how you might estimate this?  

Ilissa Ocko: Sure, there are numerous technologies and practices available to cut methane from all of these sources, which is really exciting. 

And so, the largest and cheapest opportunities lie in the oil and gas sector. And this is because fixing leaks can be as simple as tightening of valve, replacing a gasket or tuning an engine. So, the challenge is therefore not fixing the leaks, but finding the leaks. But thankfully our ability to detect methane leaks has rapidly advanced in recent years. 

We have handheld instruments, and we have sensors on aircraft and drones, and now there are satellites that can detect methane. And so,.  

Roumeen Islam: But Ilissa, if I may just mention, I understand that it's not necessarily that easy in every country to actually detect the leaks, because not every country has been doing this very successfully.  

I just read an article today about Boston, where you would think that they would be catching the leaks very well, but I guess it's not always so easy, or it hasn't been, right?  

Ilissa Ocko: Yeah, it's a really good point and that study that you're referencing was in part published by my organization. It's extremely challenging to monitor methane leaks at the end use and at the home level, with these pipes all underground and going into homes, it's incredibly difficult. We do not have good data for that. You're absolutely right.  

The methane leaks that are easier to detect with these types of technologies, I mentioned are from the production facilities where they're more concentrated and we have better systems in place now that we've been developing over the past decade.  

And for countries that don't have the equipment that we have, for example, in the United States, where we've been able to really scale up our monitoring of methane leaks from oil and gas producers, that's where the satellites will come in. And so EDF is building a satellite called MethaneSAT that will be ready to be launched next year and will be able to detect methane emissions globally with unprecedented precision relative to the technologies that exist right now.  

So, we will have for the first time, global access to these methane leaks across all sorts of different areas. And that will really help us identify where these leaks are coming from so that we can know this information as soon as possible, and then send in the proper personnel to plug these leaks up.  

Roumeen Islam: That’s fantastic, I look forward to this. Please continue, you are going to talk about other sources of methane abatement?  

Ilissa Ocko: Yes. So, for waste management, there are also a lot of opportunities to reduce emissions.

And some of the strategies includes sucking up methane from landfills and just simply treating wastewater in a way that isn't typically done in certain parts of the world. In terms of agriculture, cutting methane emissions is more difficult than the other sectors, especially livestock. The latest proven technology to reduce methane emissions from cattle digestion suggest at least 30 percent of emissions could be reduced through feed supplements, and reducing methane from manure with improved management practices, such as covering manure lagoons, could also reduce emissions by at least 30 percent globally.  

For rice production, there are practices that can cut methane emissions in half such as occasionally draining rice fields. The challenge here is that it isn't clear if these strategies would increase another greenhouse gas, nitrous oxide, as a side effect, but there's growing evidence that if we just maintain a shallow layer of water in the rice fields, then we could reduce emissions of both methane and nitrous  oxide. 

So, all of these estimates come from established assessments that are publicly available and published in recent years. And my colleagues and I synthesized all of this available information, and we found that implementing all these solutions could cut methane emissions in half over the next decade, which would slow down the rate of global warming by as much as 30 percent in the following decades. 

Roumeen Islam: Okay. That's good to know. So, in some research of yours, you consider two types of mitigation scenarios. The first is actions that can be achieved at no net cost, for example. So, could you expand on this? Cause that sounds like an attractive option.  

Ilissa Ocko:  In our study, we really wanted to bound our analysis by looking at two extreme cases. One that is extremely feasible. And one that is just entirely available if we go all in. So, the first is only implementing methane mitigation that has zero net cost, or that companies have worked into their business models. So, for the former, the “no net cost”, this means that any costs in implementing the methane mitigation measures, such as detecting and repairing gas leaks from pipelines, is balanced by the money saved from the same measure.  

Roumeen Islam: Because you would sell it. 

Ilissa Ocko: Exactly. You save your product because you are not wasting it anymore and you're selling it to your customers. So, another example is for landfills or manure, this would mean capturing the landfill gas and then using it to produce electricity or heat. So, you save money from using the methane and you're preventing it from escaping into the atmosphere. 

And so, for oil and gas producers, in addition to just including the “no net cost” options, we also include commitments that have been recently made by major oil and gas companies. So, these companies that are responsible for one third of global oil and gas production have committed to reduce upstream methane emissions to 0.25 percent of total production over the next several years with the ambition to achieve 0.2 percent. 

And they did this through a coalition called oil and gas climate initiative. And so, we include those commitments that these companies made into our most feasible option and this, like economically viable, no net cost, scenario that we look at. And when we consider all these abatement opportunities globally, for all major methane sources, we find that around 20 percent of emissions can be reduced for no net cost in the absolute sense, meaning that the solutions pay for themselves. And that when we include the oil and gas company targets, a quarter of emissions can be reduced.  

Roumeen Islam: Very good. Thanks, Ilissa. Now, what about the second type of abatement possibilities that you looked into.  

Ilissa Ocko: The second case we consider is all methane reductions that are possible with existing technologies and strategies, regardless of cost. 

So, in a sense, this is also still feasible because this doesn't rely on technologies that we have yet to develop, but at the same time, the costs are higher. So, it's not a given that we can just go ahead and pursue all these options. But because it is technically available, it's important to consider this case to show, “well, here would be all of the benefits that you would get if you actually could do this.” 

And so, when we add up these measures, we find that we could reduce half of methane emissions from human activities. And again, this does not include any new technologies that are on the horizon. And so those technologies that are being explored right now could certainly increase the abatement potential if they come to fruition. 

And so, a couple of examples are the ongoing research to suck methane out of the air or to reduce even more methane from cattle digestion, using new types of feed supplements that actually use seaweed to help suppress methane production in cows’ guts.  

Roumeen Islam: Yeah. I know, I've been hearing for some years now about how cattle digestion affects methane. Let's move on to why we need to focus directly on methane mitigation and why a carbon tax isn't sufficient. Methane is also a carbon compound.  

Ilissa Ocko: Correct. But carbon is often used to just refer to carbon dioxide. And you're absolutely right, methane is a carbon compound.  

But if a carbon tax does only focus on carbon dioxide, it will not address methane emissions directly, but only indirectly reduce these emissions associated with fossil fuel activities, because that's the one common source for both methane and carbon dioxide emissions. 

So, a carbon tax would encourage less fossil fuel activities, which would then reduce emissions of methane. But what about the methane from agriculture? And what about the methane from waste management? And so, there's these other key sources that are not considered if it’s just a carbon dioxide tax.  

Now, if a carbon tax includes methane, but it uses the standard accounting approach for converting methane into its carbon dioxide equivalence that I discussed earlier, then it will undervalue the importance of reducing methane. 

Roumeen Islam: So, you need direct measures even for the oil and gas sector.  

Ilissa Ocko: Absolutely. Yes. There's a lot of evidence that directly addressing methane emissions from oil and gas, even if we were to aggressively wean ourselves off oil and gas, we would get a lot more climate benefits faster and more efficiently by plugging these leaks even if we aggressively decarbonize the energy grid.  

And so, either way, there's just a lot more methane, you could cut through direct methane mitigation than relying on a carbon tax. And so, there's just a lot of benefits that we can get from directly addressing methane. And so, it makes sense to pursue those options. 

Roumeen Islam: All right. So how do you account for the vast differences that there are across countries in terms of where they're leaking methane from, and in terms of the abatement technologies available to them. I don't know whether you account for these differences, and if so, how?  

Ilissa Ocko: The abatement assessments that we synthesize for our research already account for differences across countries. And in many cases, these studies actually provide abatement potential information on a per country basis.  

Roumeen Islam: That's excellent!  

Ilissa Ocko: Yeah, taking into account all the different types of practices and all the specific abatement potentials depending on that specific country. And so, in our study, we use the global sum to then calculate the global climate impacts. But the underlying information draws heavily on regional information.  

Roumeen Islam: That’s very good to know.  

Ilissa Ocko:  One particular example is that there's much greater potential to reduce methane from landfills and wastewater in developing countries than countries like the U.S., because in the U.S. we're already deploying a lot of this technology. 

So, that's considered in these assessments. But in terms of going forward in scaling up these solutions, there will certainly be regional challenges. There is a large diversity in systems and practices across world regions. So, it's hard to just apply one solution across the board. There are cultural differences, information gaps, different costs, and other barriers that will make implementation of all these solutions difficult on a global scale. 

The bottom line is that we have the technologies and strategies available right now. So, this is not a technology barrier, which I would argue can be a more concerning challenge if we need to do something and don't have the technology to do it. So, while it is certainly an ambitious goal to deploy the full set of solutions by 2030, given that it isn't out of the realm of possible, because we have the technologies, it's important to make known the incredible climate benefits that we could achieve, if we succeed in scaling up all of these solutions.  

And so, what we find is that we could avoid a quarter of a degree Celsius of warming by midcentury, and as much as a 30 percent slowdown in the rate of warming, if we scale up these solutions right now.  

Roumeen Islam: You also look at several timelines. So, could you speak a bit about what they are and what differences in outcomes you can see, depending on which timeline we go with. 

Ilissa Ocko: Yeah, so we certainly focused on rapidly scaling up all of these solutions, but we did consider alternative timelines to show what would happen if we don't do everything we can right now. And for these alternative timelines, we look at, what would happen if we start acting now, but we move slowly and we only fully deploy these solutions by 2050. 

Or another case where we wait and we don't start acting until around 2040 and finish by 2050. And so, we find that the first “go slow” approach that pushes full adoption of better practices out from 2030 to 2050 means a five percent increase in the average worldwide warming rate and an extra tenth of a degree Celsius by 2050 compared with the faster action case. 

And if we delay action, and we try to squeeze it into a period between 2040 and 2050, which would help us achieve net zero goals by midcentury that would result in a 20 percent faster warming rate and an additional two tenths of a degree Celsius by 2050, compared with a fast action plan that starts now.  

Roumeen Islam: So, in order to estimate the impact of methane emissions and abatement on temperature, there are a number of estimations that need to be done. So how do you do it? I know there are many models and I wonder if you could talk a bit about the one that you use.  

Ilissa Ocko: Absolutely. There are so many climate models and there are also different classes of models. So, for example, there are very simple models that are essentially an equation or two that calculate global features. 

And there are extremely complicated models that have countless equations that simulate all different parts of the climate system and couple them together, and then provide information for a globe that is divided up into hundreds of different parts.  

And so, for analysis, such as ours, where you have dozens and dozens of model scenarios, but they can represent small changes in the Earth's energy balance at certain points in time, the class of models that is most appropriate is called “reduced complexity climate models.” They are in between the very simple models and the very complex models. And so, they include many more physical processes and interactions and chemical reactions than the simple models, but they don't take weeks to run on very intense, super computers. They don't include unforced variability that then drowns out a small signal among the noise. And that's what these complex models would entail.  

So, for this study, we use a reduced complexity model called MAGICC. Which is Model for the Assessment of Greenhouse Gas Induced Climate Change.  

Roumeen Islam: I like this name, MAGICC. 

Ilissa Ocko: I know it's a fantastic name and this model has been around for decades. It's been used in several policy-oriented climate analysis that involves short-lived climate pollutants. It's been refined for decades and tuned to produce similar results as the more sophisticated models and my colleagues and I actually validated its performance for simulating climate responses to methane emissions in particular several years ago.  So, we feel really confident in its ability to reproduce climate responses to methane emissions.  

Roumeen Islam: That's very good to know. So, you've done a lot of research and you've also looked at a lot of research that's been done by other researchers. 

So, I wanted to ask you, as we near the end of the podcast, what do you think are the next steps in research for policy purposes? Where do you think we need more information?  

Ilissa Ocko: Temperature change is what we've focused on as the indicator of why methane mitigation is important. And temperature is an important climate change indicator. But it's not nearly as powerful in motivating policy as the more direct impacts to society and ecosystems such as worsening extreme events, crop damages, health risks, sea level rise and many other damages that we face. 

So, an important next step is connecting methane mitigation to the tangible benefits for societies and ecosystems worldwide. And that is something that my colleagues and I are actively working on doing right now.  

Roumeen Islam: I really look forward to seeing this research. So, before we end, would you like to say something?  

Ilissa Ocko: I guess I'll just end by saying that

So, I really appreciate the invitation to come on your show, to talk about this exciting opportunity we have in front of us. 

Roumeen Islam: Thank you, Ilissa. This was really a very informative and interesting discussion today. Thank you very much.  

Ilissa Ocko: Thank you. 

Roumeen Islam: Well listeners, let me sum up the main points for you. We heard that , given methane’s much stronger capacity to warm the planet in the short term.  

Secondly, there are many measures that can be taken at no net cost. That means that

Thirdly,  That’s a lot. The longer we delay, the higher will be the cost in terms of global warming.  

This is all for today. If you have a topic that you would like to learn more about, please email me at Thank you. And bye for now. 


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