Eight cutting-edge technologies that capture carbon
Eight new technologies that could lead to negative carbon emissions
Combating climate change effectively will take more than simply reducing greenhouse gas emissions. We are going to need to enable negative emissions. Here are eight cutting-edge technologies that are aiming to do that.
1 More forests
The world’s forests have absorbed as much as 30% of annual global human-generated CO₂ emissions over the last few decades.
Regenerating depleted forests (reforestation), planting new forests (afforestation), and protecting and helping existing forests thrive through active management can all contribute to forest growth.
A recent report from the Intergovernmental Panel on Climate Change (IPCC) estimates that reforestation and afforestation could potentially capture 0.5 and 3.6 billion tonnes of CO₂ a year at a cost of USD $5 to $50 (£3.90 to £39) per metric tonne.
2 More bioenergy with carbon capture and storage
Biomass can also help industries including power generation lower emissions. During its lifetime it absorbs carbon from the atmosphere (often enough to offset emissions from transportation and combustion).
Combined with carbon capture and storage (CCS or CCUS) technology, biomass becomes a negative carbon emissions process, known as BECCS.
Drax Power Station is partnering with carbon capture company C-Capture to develop BECCS technology. This could help turn Drax into the world’s first negative emissions power station.
The IPCC estimates that between 0.5 and 5 billion metric tonnes of carbon could be captured globally this way at a cost of $100 to $200 (£80–160) per metric tonne.
3 Increased ‘blue carbon’
Coastal vegetation such as mangroves, salt marshes and sea grasses sucks in and store carbon in soil at a greater rate than plants on land– known as ‘blue carbon’.
Efforts are underway to turn these ecosystems into carbon sinks that can remove more emissions from the atmosphere. For example, Apple is currently supporting a mangrove expansion project in Colombia.
4 Boosting ocean plants’ productivity
The oceans are already believed to be one of our planet’s biggest carbon sinks — full of plants that use CO₂ to photosynthesise. Now projects are attempting to make them even more efficient.
One approach involves injecting iron nutrients into the oceanto prompt a bloom in microscopic plants called phytoplankton, which float in the upper part of the ocean absorbing the CO₂ absorbed from the atmosphere. When the plants die they trap the absorbed carbon on the seabed.
5 Enhanced rock weathering
Experts are trying to speed up this process by pulverising rocks and spreading the resulting powder over a larger area — absorbing more CO₂ from rain and air.
The IPCC estimates that at scale this could capture 2 and 4 billion metric tons at a cost of between $50 and $200 (£39–160) per metric ton.
6 Capturing carbon in soil
Changing farming methods could help make agriculture carbon neutral. Straightforward techniques such as minimising soil disturbance, crop rotation and grassland regeneration could capture up to 5 billion metric tonnes of carbon in the soil annually, according to the IPCC, at potentially zero cost.
7 Increasing soil carbon with biochar
A type of charcoal made by burning biomass, such as wood or farm waste, in the absence of oxygen, biochar can increase the amount of carbon locked into the soil for hundreds or thousands of years. It also helps soil retain water, and reduce methane and nitrogen emissions.
The IPCC estimates that this could capture between 0.5 and 2 billion metric tonnes of CO₂ annually. However, cost and sourcing sustainable biochar pose a challenge.
8 Direct air capture
Direct air capture (DAC or DACCS) proposes that the carbon capture and storage technology, that many power stations are now trialing, could be carried out almost anywhere.
Swiss start-up Climeworks is one company attempting to make DAC viable by passing air through a surface that reacts with CO₂ to form a compound, but releases the remaining air. The main challenges for DAC are the costs — between $200 and $600 (£156–468) per metric tonne — and the large amounts of energy needed.
Hope for the future
A Royal Academy/Royal Society report released earlier this year concluded that Britain could become net zero and do its part in mitigating man made climate change — with BECCS identified as the negative emissions technology best suited to take the leading role and at least cost.
