Some people have called me a doomer. Others call me a pessimist. Some people even call me a denier. While others call me a pain in the neck. Personally, I think I’m a realist.
If I look at the plans that most nations have made to limit their contribution to climate change, I think it just isn’t going to happen. The people making these plans are either ill-informed, delusional, or lying, or maybe all of the above. Now there’s a new publication just out of the University of Melbourne in Australia that, according to the press release, has revealed a “huge climate mitigation challenge” and claims that the IPCC has overestimated how much carbon dioxide removal can realistically accomplish. Yes. Let’s have a look.
Okay, I admit, I’m partly talking about this because I feel like some people have misunderstood my position on what we should do about climate change. They’re probably confused because I’ve said both that (a) we need to get serious about carbon dioxide removal and (b) carbon dioxide removal isn’t going to save the day. On top of that I have also said it's too late to do anything now. We're toast! So how do these these things fit together?
Well, it’s because I’m a doomer. Ooops no, sorry I mean, realist. I’m a realist. Carbon dioxide removal isn’t going to help much, but it’s going to help a little, and in contrast to the idea that we’ll “just stop oil,” I can not see it actually happening. Ever.
If you’re wondering why I have difficulties believing that we’ll stop using fossil fuels, let me tell you a little story from the local neighborhood. A couple of months ago they drilled a hole about 30 kilometers north of here. They found oil. The company reports happily that the oil is of very high quality, and now they’re building a well. Does this look like we’re going to stop using fossil fuels? Because it’s not what it looks like to me. Not here, not anywhere. So, carbon dioxide removal. Not great. But better than nothing. Let’s do it.
So much about me, but I wanted to talk about this new paper. First though, I need to sort out a terminology issue. Because I’ve noticed that a lot of people confuse Carbon Dioxide Removal, Carbon Capture and Storage, and Direct Air Capture. These are three different things.
Carbon Dioxide Removal is anything that reduces carbon dioxide levels in the atmosphere. Trees, for example, do carbon dioxide removal, but any technology which mimics this process also counts.
Carbon Capture and Storage, in contrast, is a way of partly preventing the emission of carbon dioxide, for example, on power plants. But it doesn’t entirely prevent the emission. So if you do it at a fossil fuel plant, that does not remove carbon dioxide from the atmosphere, it just reduces the emission. Therefore, Carbon Capture and Storage at fossil fuel plants is not a method of carbon dioxide removal.
However, if you do carbon capture and storage when burning biomass, then you actually do reduce the carbon dioxide in the atmosphere because the biomass, such as trees, are what took the carbon dioxide out of the air. This is called bioenergy with carbon capture and storage, BECCS for short. It is also a way of producing energy. Yes, you can actually make energy by removing carbon dioxide. Who knew? And since you can make energy and therefore money with it, this has been the most popular way of doing it. People love making money.
And finally, Direct Air Capture is a different method of carbon dioxide removal. It basically works by pumping air through huge filters and trapping the carbon dioxide. It’s highly inefficient because the density of carbon dioxide in the air is quite low and also it takes up energy. There are only a few experimental direct air capture installations to date.
There are some other methods of carbon dioxide removal - seawater extraction, biochar, enhanced weathering, but the currently most widely used one is BECCS. If someone tells you that carbon dioxide removal basically doesn’t exist, they’re probably confusing carbon dioxide removal with direct air capture.
It’s clear now that there’s no way we will limit warming to below 2 degrees without carbon dioxide removal. The International Energy Agency concluded in a report from 2022 that reaching net zero by 2050 is “virtually impossible” without carbon dioxide removal. The IPCC too writes very clearly that carbon dioxide removal “is part of all modeled scenarios that limit global warming to 2 degrees or lower by 2100.”
Okay, the thing is now that all plans to get to net zero by 2050 rely on extensive carbon dioxide removal in some way. Given that the currently biggest contributor is Bio Energy with Carbon Capture and Storage, a lot of people put their hopes on that.
And this then brings me to the new paper. The IPCC draws conclusions by working out what they call “mitigation pathways” that are basically possible courses of action. The authors of the new paper now say that as far as Carbon Dioxide Removal are concerned those pathways proposed in the IPCC report are not only unrealistic, they’re actually problematic.
They write that Carbon Dioxide Removal deployments, quote “pose major economic, technological, and social feasibility challenges; threaten food security and human rights; and risk overstepping multiple planetary boundaries, with potentially irreversible consequences” end quote.
As I said the major method of carbon dioxide removal is currently bioenergy with carbon capture and storage. And the problem is that to scale this up, you need all this bioenergy in the first place. That means in practical terms you need to grow stuff, and growing stuff needs land, land that other people might want to use for other things.
The authors of the new paper looked at the numbers which the IPCC assumes for this technology. The IPCC projects that BECCS could remove up to 10 or 11 billion tons of carbon dioxide per year. The authors then estimate that this would, quote: “require converting up to 29 million square kilometers of land—over three times the area of the United States—to bioenergy crops or trees, and potentially push over 300 million people into food insecurity” end quote.
They say that a realistic estimate would be more like 2 to 3 billion tons of carbon dioxide per year removed by this method, which is about a quarter of the IPCC estimate. Basically, this means that even the IPCC plans to limit warming to 2 degrees are unrealistic.
Though personally I think one doesn’t need a paper published in Science to see this. You just need to know that at the moment the amount of carbon dioxide that we actively remove mostly by BECCS is a little more than 2 million tons a year. Doesn’t look likely that we’re going to reach 2 billion anytime soon. While removing 11 billion tons of carbon dioxide per year is a fantasist delusion.
The paper is here: Sustainability limits needed for CO2 removal
The true climate mitigation challenge is revealed by considering sustainability impacts
Alexandra Deprez et al Feb 1 2024
https://www.science.org/doi/10.1126/science.adj6171