Wednesday, October 20

Trials to suck carbon dioxide out of the air to start in UK | Emissions of greenhouse gases


Climate-warming carbon dioxide will be sucked out of the air using trees, peat, rock chips and charcoal in major new tests across the UK.

Scientists said past failure to quickly cut emissions means some COtwo They will need to be removed from the atmosphere to reach net zero by 2050 and stop the climate crisis. The £ 30 million government-funded project will test ways to do this effectively and affordably on more than 100 hectares (247 acres) of land, making it one of the largest trials in the world.

Degraded peat bogs will be rewetted and replanted in the Pennines and West Wales, while rock fragments that absorb COtwo As they decompose in the soil, they will be tested on farms in Devon, Hertfordshire and central Wales. The special charcoal called biochar will be buried in a sewage landfill, in old mines and railway embankments.

It will also examine the best large-scale ways to use trees to sequester carbon across the UK, including on Ministry of Defense and National Trust land. The latest test will measure the carbon removal potential of energy crops like willow and miscanthus grass for the first time on a commercial scale. These crops would be burned for energy, with the COtwo emissions trapped and stored underground.

“This is really exciting and practically world-leading,” said Professor Cameron Hepburn of the University of Oxford, who is leading the coordination of the trials. “Nobody really wants to be in the situation of having to suck so much COtwo of the atmosphere. But that’s where we are, we’ve lagged behind [climate action] for a long time.”

He stressed that reducing emissions from burning fossil fuels as quickly as possible remains vital to addressing global warming: “There is no suggestion that [CO2 removal] it is a substitute for reducing our emissions ”.

Scientists from the Intergovernmental Panel on Climate Change have concluded that there is no way to keep global temperature rise within the internationally agreed target of 1.5 ° C without reducing emissions and removing billions of tons of CO.two one year to 2050. Official UK Climate Advisers estimate that the UK is likely to need remove around 100 million tons of COtwo one year to 2050 to reach net zero.

Carbon removal is also seen as essential because it will be difficult to stop all emissions from sectors such as aviation, agriculture and cement by 2050. The new trials are part of a £ 110 million government program which also includes testing of the use of technology to purify COtwo straight from the air.

The focal point for new trials will consider social, ethical and legal issues related to carbon removal. For example, Hepburn said, “If you’re crushing rocks and putting them in the ground to grow food, then you want to make sure what goes into the food system is completely safe, I’m sure it will be.”

There is a current debate about whether companies could use carbon removal to offset their emissions, rather than reduce them, and whether such offsets can be guaranteed to be genuine.

“We are very vigilant about the possibility that companies simply use compensation as greenwash,” Hepburn said. “Part of what this program is about is developing the monitoring, reporting and verification frameworks to ensure that the removals are genuine.”

Improved rock weathering

Basalt chip diffusion in fields will be tested on arable and grazing land. Chemical reactions that degrade rock blocking COtwo in carbonate minerals in months. Up to 13 tons of COtwo per hectare could be closed every year. In degraded soils, rock chips can also help reverse acidification and replenish essential plant nutrients. “The joy is that if you kidnap COtwo and lead to higher agricultural productivity, then everyone laughs, ”Hepburn said.

Biochar

The trial will be the most comprehensive biochar trial to date and will add 200 tons of the material to 12 hectares (29.7 acres) of arable fields and grasslands. Charcoal-like material is produced from wood or organic waste. About 10 tons of biochar per hectare can be added to crop fields, but 50 tons or more could be buried under grasslands. Biochar increases the soil’s ability to retain water and nutrients and can help prevent runoff of fertilizers and pesticides.

Perennial bioenergetic crops

Battered willow and miscanthus herb can provide fuel for power plants and remove COtwo from the air if the exhaust gases are captured and stored underground. The test will look for the best varieties and planting methods and will assess how much carbon is also stored in the roots of the plants. Twenty hectares will be planted and current estimates are 11-18 tons of COtwo being eliminated per hectare each year.

Peat bogs

Today damaged peat bogs are the UK’s largest source of CO.two Land emissions and trials aim to reverse this by blocking drainage and raising water levels. In the lowland trials, the former agricultural land will be converted into a “carbon farm” and in the upland trials the peat will be restored through measures such as planting sphagnum moss. A restored peat bog could absorb 10 tons of COtwo/ ha / year, in addition to preventing the loss of about 30T of COtwo/ ha / year. The renovated peatlands will also help wildlife, flood prevention, and water quality.

Large-scale tree planting

“Trees represent the most profitable way to remove COtwo from the atmosphere, while also offering benefits such as improved biodiversity and recreational and health improvements, ”said Professor Ian Bateman of the University of Exeter, who is leading these trials.

But he warned that planting trees can have disastrous consequences, if they are planted on peat and release carbon, for example. The tests will test how to plant the right tree in the right place. The trees will be measured and also inspected by drones and the accumulation of carbon in the soils will be monitored.

Up to 13T COtwoIt could be stored e / ha / year, and Bateman said: “You can start now, you just need soil and plants. There is great potential to make an immediate difference towards the goal of net zero by 2050. “


www.theguardian.com

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