Greenhouse gas removal ‘not a silver bullet for net zero’ | Carbon Capture and Storage (CCS)

Many of the UK’s leading scientists working on carbon capture technologies do not believe that they will be developed and scaled up in time to reach net zero and Limit global heating to 1.5°C.

Experts speaking at a greenhouse gas removal event in London warned that these technologies, including live air capture, Biofuels, biochar, afforestation, and advanced weathering are not a silver bullet and should make up a small part of efforts to decarbonize.

The researchers were polled by event organizers on whether they believed the decarbonization goals would be achieved. Of the 114 scientists in attendance, 57% said they were “not confident” that the UK would meet its 2030 targets in a net-zero strategy of 5 million tonnes of engineered greenhouse gases, and 30,000 hectares annually from tree planting; 25% said they were completely confident, and 11% said there was no chance.

Scientists participate in 70 million pounds Government funded competition To find the best ways to remove greenhouse gases from the atmosphere. These technologies are set to begin removing massive amounts of carbon dioxide from the atmosphere by 2030, with the hope that winning methods will be scaled up and ready for commercialization within two years.

The government, in general, appears confident that carbon capture methods will be developed fairly quickly. The Department for Transport, for example, has said that greenhouse gas removal (GGR) technologies will enable Britons to take “guilt-free journeys” by the end of next year, but program participants were less optimistic.

but when Show press release Of the government declaring that these technologies will enable net-zero flights by 2023, Professor Mark Taylor, deputy director of energy innovation at the Department for Business, Energy and Industrial Strategy (BEIS), sounded skeptical. He told the Guardian: “No, that’s not the case. We have to get people to think this could work, but maybe that claim is a bit rude.”

“GGR is difficult and expensive,” said Gideon Henderson, chief scientist at the Department of Environment, Food and Rural Affairs (Defra). “We cannot afford to see it as an alternative to offsetting continued emissions in decarbonized sectors. It is not an excuse for not decarbonizing, so we must reduce emissions. In any case “.

By far the most popular application-based technology in the program has been live air capture. This process involves removing carbon from the air, usually with giant fans, and heating it to a very high temperature. This carbon can then be stored in geological formations or combined with hydrogen to produce synthetic fuels.

While ministers admire this idea, those leading the program believe it may not be the answer, due to the energy density required and how expensive it is.

“People see it has the biggest market,” Taylor said, “there’s corporate funding from America — it feels like a silver bullet, there’s a lot of people who like it. Ministers like it because they think, ‘Oh, that looks easy, you can take it off the air and that’s it. And that’s the thing that gets the investment.

“I am very conservative about whether this is the best solution. It is very expensive. So some other technologies may emerge as winners, but the good thing about our competition is that we choose the best.”

The Guardian has reached out to BEIS for comment.

Greenhouse gas removal methods under trial, funded by the United Kingdom

afforestation
This is GGR’s “poster child,” Henderson said, because “everyone seems to like it, and it’s good to have more trees.”

However, he said, trees are “not a panacea” because of the amount of land they need, that are taken out of food production, which then causes tensions with food security. There is also tension between forests, which have more biodiversity benefits but are slow to grow, and forests, which grow quickly and sequester more carbon sooner.

Storage in the soil
While storing carbon in soil is a common method, according to Henderson, there are concerns about how long soil carbon can be stored and how it is measured. If soils start releasing carbon again soon after it is stored, it can cause problems, especially if it is not effectively measured and accounted for in net zero targets.

He explained, “I think if we see significant financial resources coming into this area to stimulate soil carbon storage without being able to measure it, and make sure that it is sustainable, then there is a risk of continuing emissions from storage that is not always or has been measured well enough.”

advanced weathering
Dropping tiny rock particles into the sea in order to trigger chemical reactions that trap carbon in the ocean is potentially a very exciting technology, but it’s at an early stage than many other carbon sequestration methods. It has interesting potential, as the ocean stores carbon in higher concentrations than air. There is even hope that it can help Reversing ocean acidification. However, there are concerns that this process could upset the delicate balance of the oceans.

Live air pick up
The idea of ​​a machine that could suck carbon dioxide out of the atmosphere and permanently stick it into rocks is very attractive, and perhaps not surprisingly, this is the most popular technology for scientists trying to solve this problem.

But at the moment it is an energy-intensive process. Taylor explained: “We need to use energy to extract carbon dioxide2pure current company2 from the solid, so what we are looking for is an integration that can lower DAC costs, especially lower the cost of CO2 extraction2 and the energy costs of extracting carbon dioxide2. Because right now, there’s no point in capturing carbon dioxide2 from the air and then use natural gas to conduct a thermal process to extract pure carbon dioxide2 Stream.”

Biofuels
While Henderson noted that this is carbon storage that is already occurring on a UK scale, and could be a “really effective form of greenhouse gas removal”, there are concerns about biodiversity and pressure on land use. This is because growing crops often results in monoculture, and this land is taken out of production for food.

Biochar
Biochar is a stable, long-lived carbon-like product produced from heating biomass in the absence of oxygen. It is rich in carbon and can be used on Earth to sequester carbon dioxide2 in the soil for a long period of time. This may be relatively easy and cheap, but there are concerns about how long the carbon will be stored, and whether it will have any negative effects on the soil.