What is Greenhouse Gas Removal?

The earth’s climate is changing as a result of greenhouse gases (including carbon dioxide) released into the atmosphere by human activity. Humanity urgently needs to reduce the amount of greenhouses gases we release, to try to reduce the effects of global warming.

Some industries won’t be able to reduce their emissions to zero quickly enough, so technologies that take greenhouse gasses out of the atmosphere are needed to balance them out to reach net zero, this is called Greenhouse Gas Removal (GGR).

There are many different types of GGR, with biochar being just one option. The Biochar Demonstrator is part of the UKRI Greenhouse Gas Removal Demonstrators (GGR-D) Programme, an ambitious new research programme studying options for effective, large-scale GGR. Alongside biochar there are 4 other demonstrators and a coordinating hub (CO2RE) as part of the programme, researching different GGR technologies and helping to shape the path for the UK to reach net zero.

The other demonstrators are investigating:

  • Afforestation (Woodland)
  • Enhanced rock weathering
  • Peatland restoration
  • Perennial biomass crops

Tell me more about…

Trees are vital for our planet and because they naturally absorb carbon dioxide, they represent the most cost-effective way of removing carbon emissions from the atmosphere. At the same time, they deliver many other benefits such as enhanced biodiversity and recreational and health improvements. 

However planting trees without proper planning can have disastrous consequences. For example, planting trees on peatland can release vast quantities of naturally-stored carbon and methane into the atmosphere.  The afforestation project, NetZeroPlus, will explore all the diverse aspects of forestry to identify “the right tree in the right place”.

Silicate rocks, such as basalt, absorb carbon dioxide as part of the natural chemical reactions that continuously erode away rocks over millions of years. As part of a process called enhanced rock weathering (ERW), silicate rocks are crushed and spread over farmland. Crushing the rocks gives them a greater reactive surface area, so they can absorb more carbon dioxide. The process may also improve crop health and increase yields.  

The ERW project will explore amending soils with crushed calcium and magnesium rich silicate rocks from waste quarry fines to accelerate natural carbon dioxide sequestration processes..  

Peatlands are carbon-rich wetlands which occupy 10% of UK land area. Peatland plants capture carbon dioxide through photosynthesis. The acidic and waterlogged habitat of healthy, functioning peatlands mean that when plants die, they decompose extremely slowly and so store the carbon in the ground. However, as a result of human disturbance our peatlands are drying out, and decomposition restarting do they’re rapidly losing this carbon to the atmosphere.  

The GGR-Peat project will work with natural processes to restore, and where possible enhance, the environmental conditions that lead to peat formation, while developing innovative approaches to increase rates of carbon dioxide uptake and store it securely for millennia. 

Crops such as miscanthus grasses and coppice willow can be grown and then their biomass burnt to generate energy. Because plants capture carbon dioxide as part of photosynthesis, the energy derived from burning them is largely carbon neutral. If the carbon dioxide produced is captured and stored underground, the process is carbon negative. This is known as Bioenergy with Carbon Capture and Storage (BECCS). Because the crops are perennial (they live for several years), they provide a renewable source of biomass and simultaneously sequester carbon into the soil via their roots. The biomass produced has many other potential uses, for example in the construction industry and as a source of high value chemicals.

This demonstrator project investigating these crops is called PBC4GGR (Perennial Biomass Crops for Greenhouse Gas Removal).

CO2RE is a multidisciplinary team of some of the UK’s leading academic experts on GGR. The project co-ordinates the GGR-D Programme and conducts solutions-led research to evaluate a balanced portfolio of economically, socially and environmentally scalable GGR options, with associated policy design, engagement and outreach. The work of CO2RE will enable the UK to lead internationally on achieving global net–zero emissions, consistent with the Paris Agreement.