The Exchanges

Q net zero by twenty-fifty or, you know, two degrees Celsius of warming or, or whatever it might be. And I think what you're, part of what you're saying is that those in and of themselves don't necessarily reflect the fluctuations over time in emissions, and those fluctuations over time in emissions could actually have a really big impact on what climate change does to people and ecosystems. Is that right?

A That's right, and let me give you, uh, two different sort of examples. Um, so when we talk about temperatures by 2100, let's say 1.5 degrees C, uh, the question here is, what's the path from here to 1.5 by 2100? And what the climate models show is that there are a wide number of trajectories, some of which have what is called high overshoot, and others of which have what is called low overshoot. Uh, this is How much above 1.5 do we go over the next few decades before going back down to 1.5? That trajectory matters. Um, the longer that we spend, uh, higher, the more risk we are of direct human climate impacts, as well as natural system impacts, some of which may not be irreversible, and some of which will further drive warming. The other thing that's important to understand here is that net zero by twenty-fifty is, uh, an important goalpost on the way to being able to maintain lower temperatures. However, it's not the entirety of the story. There are many different gases here that are very important, and some of which have more, uh, more near-term impact. Uh, and so Net zero by 20 50 for CO two is critically important for managing long-term warming, but we cannot forget about the other pieces primarily around short-lived client pollutants that are going to be even stronger levers towards managing that near-term warming, that peak temperature, that overshoot.

AI assessment note: “That's right, and let me give you, uh, two different sort of examples.”

Q to near-term warming. It's a particularly big problem when it comes to near-term warming. Uh, and thus we should be focusing probably more attention than we are collectively on mitigating and removing methane emissions. So let's talk about what that is going to have to look like, starting with where do the methane emissions come from? So can you just kind of give an overview of current methane emissions sources?

A Absolutely. So methane emissions are currently about 60% anthropogenic and 40% natural. Most of those natural emissions were also pre-industrial, and so we really care about the elevated emissions, which right now is primarily anthropogenic. Among the anthropogenic emissions, we have about a third that comes from livestock. Um, there's another quarter that comes from oil and gas, about 10% that comes from coal mining, Um, another 10% that comes from rice, and another about 20% that comes from waste and wastewater. So these are very different sources by and large than CO₂. Methane, uh, usually comes either from a biogenic process or leak or waste. Um, on the natural side, uh, it's mostly, uh, wetlands today, and there is concerning early evidence that these natural emissions are also increasing.

AI assessment note: “methane emissions are currently about 60% anthropogenic and 40% natural.”

Q term warming. Both are valid. They just, they're different things that we're, we're talking about. How does that play out in these climate models and these big like IPCC models and all this kind of stuff that lead to what ultimately are the, um, the goals that everybody understands, the net zero by 20 50 type goals. Like what's going on under the hood in these, in these climate models?

A So I like to call this the greenhouse gas dance. What the models actually reveal to us is that we need to be managing all of these gases in parallel in order to manage near-term and long-term warming. However, that, that nuance in the models doesn't always make its way out into our common understanding. And the reason for this is because of all the different impacts that different gases have and their different dynamics. So as I mentioned before, CO₂ is a stock gas. So right now, we have about . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . We need to grapple with is that we have actually 1.8 degrees of warming in the atmosphere today. And you'll probably say, well, no, Erica, we have one, 1.2 or 1.1 or 1.3. And that's correct. That's net warming. And the reason is that we actually have aerosols that we're emitting today that are masking about half a degree of warming. Those aerosols are also terrible for human health. And so it's really important that we stop emitting them from Industrial sites and vehicles, etc. As we do so, however, um, more of the warming that's already been caused in the atmosphere is going to be revealed to us as that aerosol mask is lifted. These aerosols have a very short lifetime, and they're generally co-emitted with CO₂. So what that ends up meaning is that as we dramatically cut down on CO₂ a…

AI assessment note: “What the models actually reveal to us is that we need to be managing all”

Q year span. But this is where things get complicated with methane, which is shorter lived and much more powerful. So can you just kind of walk through methane? Let's start with talking about its global warming potential and impact. Then we'll talk about where it comes from and how to get rid of it. Um, so what is the warming potential of methane and how do you think about it?

A So, as you said, there's many different ways of, of thinking about it. The most common ways are looking at its average impact per ton over a given time period compared to CO two. So that's what we call GWP 100 and GWP 20. GWP 100 means the average impact over a hundred year time scale and GWP 20, uh, is on average of a 20 year time scale. And so the fundamental challenge here is if you think about the impact of a unit of CO₂ that's been emitted is over time for warming, it's basically a flat line. When you think about what the impact of methane is, ah, on warming after it's been emitted, it is a sharply decreasing line. There's no way of scaling these lines to make them equivalent. We're just choosing the periods over which we're averaging. And so whenever we compare things on a GWP 100 basis between methane and CO₂, what we are fundamentally doing is actually making a trade-off, one that we're not always conscious of, between near-term warming and long-term warming. Because the same GWP 100 of a unit of methane Compared to a unit of CO₂, that methane is going to actually cause much more warming in the, in the near term, and much less warming a hundred years from now. Uh, and that's why these gases are so important to manage in parallel. We need to be managing both. However, the metrics that we currently use, um, make that really hard. It's really hard to compare, and we don't …

AI assessment note: “The most common ways are looking at its average impact per ton over a given time”

Q in those different sectors before we do. So we just talked about all the sources of methane emissions. I mean, I think one thing people appreciate more in CO two worlds is the sinks. What are the natural ways in which we, we uptake CO two? So soil and the ocean, things like that. What does the equivalent look like in methane world? Do we have significant natural methane sinks?

A We do. Um, the bad news is that they're not keeping up, and so we do see that, uh, methane is increasing in the atmosphere and accumulating there. Um, so the methane sink is quite different than the CO₂ sink, and that the methane sink is a conversion. Uh, and so, 90% of methane ends up, uh, being what's called oxidized by something called the hydroxyl radical in the atmosphere. And so this is a chemical reaction that is naturally occurring that is converting methane to CO₂ and water. Uh, so it does end up as CO₂. That CO₂ ends up having much less of an impact in the atmosphere than the methane did, given dramatic difference in global warming potential between methane and CO₂. So, 90% is, uh, Is oxidized through a very particular atmospheric pathway called the hydroxyl radical. The other 10% of the methane sink is a combination of some other atmospheric chemistry, um, as well as some soil sinks. Uh, so, um, the phenotrope, uh, bacteria and soils also consume this, the methane, uh, and convert it there, but in, in total, those are all less than 10%.

AI assessment note: “90% of methane ends up, uh, being what's called oxidized by something called the hydroxyl radical”

Q of generally feed additives for cattle, um, that come in a couple of different forms, but the main one is, uh, what's called bromiform, um, which is this compound that comes from asparagopsis, which is this red seaweed that's native to Australia that has been proven to have a meaningful, though not a hundred percent Impact on cow burps, essentially, on mitigating cow burps. What's your take on that category?

A So finding anti-methane solutions for cows is, and all livestock, is incredibly important and will be wildly impactful in helping to manage near-term warming. When we think about what the solutions are that we would hope to have, there's something that would be globally applicable, um, different geographies, um, different types of cow management, right? From, um, both Things that are in a barn and out grazing, um, be highly efficacious, right? So get as close as we can to a hundred percent reduction of methane and be low cost and easy for the farmer to apply so that this actually happens. We unfortunately don't yet have any solutions that check all of those basic boxes. We have incredibly valuable work going into solutions that are going to help take Address a, you know, a portion of that pie of emissions, but we don't yet have, uh, things that are going to take care of the vast majority. And the main reason for that is that huge numbers of cows globally are outgrazing and are not in environments where they're being constantly fed human mixed food. And the vast majority of the solutions that we have so far today, including, uh, asparagopsis, including three NOP, uh, Are things that we need to be feeding the cows all of the time. Um, there are shockingly poor numbers about this globally, um, but, uh, it's something like two to 10% of enteric methane emissions that are most likel…

AI assessment note: “solutions that we have so far today, including, uh, asparagopsis, including three NOP”

Q methane emissions and talk about the known and perhaps the, the less known Or less understood potential solutions. So you alluded to oil and gas being the category where we have the most well-known mitigants. What do you view? Well, first of all, where do the emissions come from predominantly? Where, where are we releasing methane in the oil and gas world? And what are the big categories of solutions?

A Um, so in the oil and gas sector, a large portion is, uh, leaks, um, of natural gas pipelines. So that's an area where, um, just getting better at leak detection and avoidance and repair can have a really massive immediate impact. There are also a number of process steps where certain machinery in the production pipeline, uh, also leaks methane, and some of those can be Directly changed through new infrastructure, um, uh, or sort of tightened up and improved. You mentioned coal mining before. That's a different category where the, um, the coal mine face itself has methane in it, and so, you know, where coal mining does continue, it's really important that we either take that methane off of the coal face ahead of it being mined, Or treat the methane in the air, uh, in the coal mine before it enters the atmosphere, and there's, there's ongoing work for developing those solutions.

AI assessment note: “in the oil and gas sector, a large portion is, uh, leaks”

Q All right, so I want to start with, uh, explaining an area that is, I guess, mainly the focus of Spark, or at least a big part of the focus for Spark, which is the concept of near-term warming, which I think people don't talk about a whole lot. Can you explain why, what is near-term warming, and why do we, or why do you care about it so much?

A Yeah, absolutely. So, um, near-term warming is the warming that we're going to see over the next few decades. And, um, the drivers of near-term warming are actually fairly different than long-term warming. Long-term warming is driven mostly by CO₂, carbon dioxide. Um, but another whole host of gases are driving our near-term warming. And near-term warming matters a whole bunch because if we look at sort of 1.5 and two C scenarios, we see massive overshoot. And so how well we're, we do at managing near-term warming is really dictating, uh, how much overshoot we're gonna have. Um, how are we going to manage the peak temperatures, uh, as well as the slope of warming to those peak temperatures, which have a, a, a whole host of impacts, uh, from, uh, hitting natural feedbacks and tipping points to extreme weather that we see. Uh, and currently, um, we don't have, we're, we're not We don't have a focus on near-term warming. We're not actively managing it as much as we are long-term warming, and both of these are incredibly important to be aware of and managing in parallel.

AI assessment note: “near-term warming is the warming that we're going to see over the next few decades”

Q atmospheric methane oxidation or something like that. And again, that turns the methane into CO two basically, which isn't great, but is way, way better. Uh, if you get the same amount of CO two versus the same amount of methane. So is that, is that different in terms of this, the, the balance equation around the difficulty of doing it because it's so dilute Versus the, uh, the need?

A So when we talk about what the methane sinks are, um, they are all oxidative pathways, um, and so methane removal actually basically means methane oxidation. Um, so when I talk about needing to find solutions for two ppm atmospheric level, uh, methane, all of those solutions would be oxidative pathways, and it's still incredibly hard. Um, there are, again, a number of Methods that are being researched in this area, different type of types of catalysts, different types of biological systems, um, sort of taking inspiration from the soil sink that we do have today naturally in the methane system. But even there, this is all very, very early research at this time, which, if it pans out, could be critically important for helping to be able to take us Off of potential feedback loops in the climate system. But at this stage, this is all really early scientific research, and there are not yet any atmospheric methane removal techniques that are deployable.

AI assessment note: “methane removal actually basically means methane oxidation... and it's still incredibly hard.”

Q category in oil and gas methane mitigation, um, that you hear a lot about is flaring. So you mentioned leaks in things like natural gas pipelines, but this is more in natural gas extraction, uh, where we've seen a fair amount of flaring, but also some Data and reports around methane that avoids flares and things like that. So how do you think about flaring in the suite of solutions?

A So what flaring is, is it's the combustion of methane, and that flaring is better than not flaring should you be about to emit methane. So the purpose of flaring is to combust that methane to reduce its global warming before entering into the atmosphere. Um, there are a number of problems here, though. Um, one is we would rather not be emitting anything in the first place, and so we should be avoiding the need To be releasing anything to the atmosphere, first of all. Second, where any flaring is necessary, and sometimes this is because of accumulating pressure in pipes, and it's really used as sometimes something for safety and management, it's really important that flare be very effective. And there's been a lot of recent research that has shown that flaring has not been As effective as it has been believed to be in actually fully combusting the methane. And so we, ah, even when we are flaring, we actually are continuing to emit some methane, ah, albeit much less than if we had vented that methane directly into the air, which would have been even more incredibly bad.

AI assessment note: “flaring is better than not flaring should you be about to emit methane”

Q Can you, can you just briefly explain how gases act differently? Like, what is the mechanism that causes these different lifespans and impacts?

A So each greenhouse gas has its own Atmospheric lifetime. The reason that CO₂ is so important is that its atmospheric lifetime is really, really long, and that's why it's called a stock gas. The amount of warming that's caused by atmospheric CO₂ is basically based on the accumulated emissions of CO₂. That's why it's so important that we not only pay attention to net zero CO₂, but also our path to get there. We want as low, ah, of cumulative emissions on our way to net zero. Other gases act differently though. Methane, for example, is currently causing half a degree of warming. It's about 30% of current gross, ah, warming. Methane has an atmospheric lifetime of about 12 years. Um, the reason this is so important for managing near-term warming is that by cutting Methane emissions. We actually, uh, have a cooling impact on the atmosphere. So when you cut CO₂, you stop warming it, stop warming the atmosphere even more than it already is. When you cut methane, you eventually, over about a decadal time span, start actually bringing that warming down. It's a fundamentally different dynamic. Other gases have other lifetimes. Um, some of them are even faster than methane. Uh, methane is, is Particularly important just because of its scale. That it's a short-lived climate pollutant, and that it has that twelve-year atmospheric lifetime, and there's just so much of it. There's half a degre…

AI assessment note: “each greenhouse gas has its own Atmospheric lifetime. The reason that CO₂ is so important”

Q they become plastics or something like that, where it's durably stored. You know, what you're, what you're avoiding there Is the, is flaring, so potentially avoiding the CO₂ that would have been released from the flare. Um, but as I understand, it still faces that same problem you're describing before, which is like, how effective are they? Are you, are you getting a hundred percent of the methane or not?

A Right. I mean, the, the goal as we think about any of these systems should be to minimize any type of emissions into the atmosphere, um, directly. And also, um, Uh, you know, if we're going to be burning this methane, which is an energy source, then at least let's use that for some sort of energetic or material value so that somewhere else in the system we can not be burning methane somewhere else and getting that value out of it. Um, again, ideally this is all towards a system where we want to not, no longer be, um, burning any fossil fuels for energy, but we are right now in this period where We want to be minimizing our cumulative emissions on the way to racing towards net zero CO₂ and minimal methane and other short-lived climate pollutant emissions.

AI assessment note: “the goal as we think about any of these systems should be to minimize”