Jason Dinh

You highlight the importance of both conservation and restoration in climate action, the latter meaning the removal of greenhouse gases from the atmosphere, sometimes called drawdown. You added that you are “frustrated writing about ‘drawdown’ technologies because we shouldn’t need them,” but decades of climate inaction have changed your thinking. Was there a turning point for you?

Rob Jackson

The turning point came within the past decade. Every year in the Global Carbon Project, we publish a new global carbon budget. That budget takes stock of that year’s emissions, the last decade or two’s emissions, and where we are in terms of temperature thresholds like 1.5°C and 2°C. We’ve seen the levels go up year after year. They’ve gone up 60% or so since the first meeting of the IPCC. So even after we knew about the risks of climate change, we haven’t stemmed the tide of greenhouse gas emissions. The lack of climate action and seeing us now so close to 1.5°C—we’ve run out of time.

Jason

Zeke Hausfather and Carbon Brief just published a new analysis that found that we’ll reach 1.5°C of warming around 2030 and 2°C around 2048. That timeline strikes me as interesting given what you write in the book about methane removal—you wrote that lowering atmospheric methane is the best option to keep temperatures under control in the next two decades. Has the fact that these benchmark temperatures keep advancing closer and closer affected your opinion about the necessity of doing something like methane removal?

Rob

It has. I should say, we don’t know whether methane removal is even possible yet. So I think, what I talk about in the book is first and foremost for methane, we could get to atmospheric restoration just by mitigation. If we had a magic wand and we could end methane emissions today, the atmosphere would return to pre-industrial health within a decade or two. That’s not true for carbon dioxide, where even if we stopped emitting today, there would be a trillion tons of extra CO₂ in the air for thousands of years. 

I’ve thought more about the importance of methane and possibilities like methane removal because we have so few options to slow climate change now. We really can’t do anything about the legacy emissions of nitrous oxide or carbon dioxide, so methane is the strongest lever we have for reducing temperature increases in the next decade or two.

Jason

I know you think there are some big challenges with methane removal—that it might actually be impossible. What are the biggest obstacles that the approach faces?

Rob

Energy is the biggest obstacle. Methane’s low concentration in the atmosphere means that you have to process a lot of air to destroy a ton of methane. Blowing air through a reactor, for instance, takes energy, and all of that energy must be carbon-free. The other challenge is that the methane molecule is unusually stable. If you have to heat the bulk air to hundreds of degrees to destroy the methane, it simply costs too much.

Jason

If methane only lasts a decade or so in the atmosphere, why can’t we just focus on reducing emissions and let legacy emissions drop naturally? What’s the added benefit of actually removing it from the atmosphere? 

Rob

The reason to consider options to remove methane is that there will be some legacy emissions that are difficult to end. The largest source of methane emissions comes from agriculture and food production. It’s complicated to ask people all over the world to change their diet, especially for people who may not have enough protein in their lives. 

I’m also concerned about increasing natural emissions. If tropical wetlands increase methane emissions or if the Arctic permafrost starts thawing and we see increased “natural” emissions—they’re not really natural if they’re happening by climate change—we have no technology for addressing those additional emissions. If they start to go up, we’re in trouble.

Jason

And those “natural” emissions from things like permafrost are really difficult to stop, right?

Rob

Very, very difficult. I worry a lot about Arctic permafrost. There is more than half as much carbon stored in Arctic and boreal permafrost as all the carbon in the atmosphere. We don’t want to start the process of having that frozen carbon come out as carbon dioxide, which would be terrible, or methane, which would be catastrophic. 

The more likely scenario that we see in the next decade or two is that tropical emissions start to increase. That’s because those emissions are driven by microbes, and when temperatures rise, their metabolisms crank up. Those emissions could be substantial, too. 

I use this analogy in the book: We can turn a wrench in an oil and gas field to reduce methane emissions. There’s no wrench we can turn to slow emissions from the Amazon or permafrost.

Jason

One of the unusual aspects of methane removal is that it doesn’t require capture and underground storage the way that industrial carbon dioxide removal does. Instead, the methane gets chemically reconfigured into carbon dioxide, which is released back into the atmosphere. That saves money and energy, but it also seems like we’re robbing Peter to pay Paul. We’re cutting methane at the cost of carbon dioxide, which will stay in the atmosphere for thousands of years. Is this a good trade, and why? 

Rob

It’s a good one for a couple of reasons. First, methane is more potent at heating than carbon dioxide over the short term. Over the first few decades, it’s 80 to 90 times more potent. Over a century, it’s 30 times. 

The other reason is that every molecule of methane that we emit into the atmosphere becomes carbon dioxide anyway—that’s what happens to all of it naturally. It’s a tiny amount of CO₂ relative to our annual emissions. All methane removal does is speed that conversion. 

Jason

There are a bunch of climate experts who look at drawdown pretty skeptically. That’s because the rollout of direct air capture (DAC) for carbon dioxide removal has been disastrous. It’s expensive and difficult to scale, yet the fossil fuel industry has seized it and flaunted it as a social license for them to continue emitting. The CEO of Occidental even said that it’s going to “give our industry a license to continue to operate for the next 60, 70, 80 years.” Why wouldn’t methane removal suffer the same fate of being co-opted by oil and gas interests?

Rob

It could be. That may very well be the case. However, one big difference in my mind is that anthropogenic methane emissions are dominated by agriculture. Big oil and gas do emit a lot of methane into the atmosphere—hundreds of millions of tons a year—but the dominant source comes from agriculture. Food production is very different than energy production. 

Jason

We started by talking about how close climate disruption is—1.5°C in the next couple of years, 2°C in a couple of decades. We’ve also talked about how methane removal is more of a concept than a practice at this point. It doesn’t seem set up to address the immediacy of the threat that we’re facing. You say it’s our best lever, but at the same time, the lever is not built yet. It’s just a theoretical lever. Do you see it differently?

Rob

I agree with you. I would make one strong distinction. The lever that we have today is to stop polluting the atmosphere with methane. The lever is mitigation. We can do that today in energy and agriculture. We can’t do methane removal today at scale.