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

Many of Britain’s leading scientists working on carbon capture technologies do not believe that they will be developed and expanded in time to achieve a zero and limit global heat to 1.5C.

Experts speaking at a Greenhouse Gas Removal Hub event in London have warned that these techniques, including direct air capture, biofuels, biocarbon, afforestation and high weathering, are not a silver bullet and should make up only a fraction of the efforts to decarbonize.

The researchers were investigated by event organizers as to whether they believed the carbon removal targets would be met. Out of 114 scientists in the audience, 57% said they were “not sure” that the UK would meet the 2030 targets in the network a zero strategy of 5 million tonnes of engineered greenhouse gas removal, and 30,000 hectares a year of tree planting; 25% said they were fairly confident, and 11% said there was no chance.

Scientists are taking part in £ 70m government-funded competition find the best ways to remove greenhouse gases from the atmosphere. These technologies should start removing vast amounts of carbon dioxide from the atmosphere by 2030, with the hope that the winning methods could be expanded and ready to go to market in two years.

The government seems, on the whole, to be confident that carbon sequestration methods will be developed fairly quickly. The Department of Transport said, for example, that greenhouse gas removal (GGR) technologies would enable the British to make “innocent flights” by the end of next year, but those involved in the program were less optimistic.

But when showed a press release of the government stating that these technologies will enable net zero flights by 2023, Prof Mark Taylor, the deputy director of energy innovation at the Department of Trade, Energy and Industrial Strategy (BEIS), seemed skeptical. He told the Guardian: “No, that is not the case. We have to make people believe that this can work, but maybe that statement is a little impertinent. “

Gideon Henderson, chief scientist at the Department of Environment, Food and Rural Affairs (Defra), said: “GGR is difficult and expensive. excuse not to decarbonise, so we need to reduce emissions anyway. “

By far the most popular technology based on applications to the program was direct air capture. This process involves removing carbon from the air, usually using giant fans, and heating it to a very high temperature. This carbon can then be stored in geological formations or combined with hydrogen to create synthetic fuels.

While ministers like this idea, those leading the program believe it may not be the answer, given the energy intensity required and how expensive it is.

Taylor says: “People see it as the biggest market, there’s US corporate funding – it feels like a silver bullet, there are a lot of people who like it. Ministers like it because they think, ‘ it’s the air and that’s it. ‘ And that’s the decent thing to do, and it should end there.

“I am very worried about whether it is the best solution. It’s very, very expensive. So some of the other technologies may appear to be winners, but the good thing about our competition is that we choose the best. “

The Guardian contacted BEIS for comment.

Greenhouse gas removal methods tested with UK funding

Henderson said this is GGR’s “poster” because “everyone seems to love it, and it’s nice to have more trees.”

However, he said that trees “are not a panacea” because of the amount of land they need, which is taken from food production, which then causes tensions with food security. There is also a tension between woodlands, which have more biodiversity benefits but are growing more slowly, and forests, which grow faster and release more carbon earlier.

Storage in soil
While storing carbon in soil is a popular method, according to Henderson there are concerns about how long the carbon can be stored in the soil and how it is measured. If the soil begins to release carbon again shortly after it is stored, this could cause problems, especially if it is not measured effectively and counted in net zero targets.

He explained: “I think that if we see significant financial resources coming into this area to encourage the storage of ground carbon without being able to measure it, and be sure of its consistency, there is a risk of continued leakage of storage that is not permanent or. fairly well measured. ”

Advanced weathering
Dropping tiny rock particles into the sea to cause chemical reactions that lock carbon into the ocean may be a very exciting technology, but it is at an earlier stage than many of the other carbon capture methods. It has interesting potential because the ocean stores carbon in higher concentrations than in the air. There is even hope that it could help reverse ocean acidification. However, there are also concerns that the process could upset the delicate balance of the oceans.

Direct aero capture
The idea of ​​a machine that can suck carbon dioxide out of the atmosphere and fix it permanently in rocks is very appealing, and it may come as no surprise that this is the most popular technology for scientists trying to solve this problem.

But it is currently a very energy-intensive process. Taylor explained: “We need to use energy to extract the CO2the clean stream CO2 of the solid, so what are we looking for integration that can decrease the costs of DAC, and especially decrease the cost of extraction of the CO2 and the energy costs of extracting the CO2. Because nowadays, it is useless to capture CO2 from the air and then using natural gas to power a heat process to extract pure CO2 stream. ”

While Henderson stressed that this is carbon storage, which is already happening on some scale in the UK, and could be “a really powerful form of greenhouse gas removal”, there are concerns about biodiversity and pressure on cultivation. This is because growing the crops often creates a monoculture, and this land is taken from production for food.

Biocarbon is a stable, long-lived, carbon-like product produced by heating biomass in the absence of oxygen. It is carbon-rich and can be applied to soil to sequester CO2 in soils for a long time. This could be relatively easy and inexpensive, but there are concerns about how long the carbon would be stored, and whether it would have any negative effects on the soil.

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