POST - Parliamentary Office of Science and Technology

Greenhouse Gas Removal

Published Friday, February 3, 2017

The 2015 Paris Agreement called for a balance between sources of Greenhouse Gas (GHG) emissions and their removal by 2100 to halt global temperature rise. This POSTnote explains why Greenhouse Gas Removal (GGR) techniques may be required to achieve this goal, outlines the benefits of and concerns about them, and considers policy options.

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The active removal of GHGs from the atmosphere, referred to as negative emissions, could be achieved using a variety of techniques. GGR techniques mainly focus on the removal of carbon dioxide (CO2) from the atmosphere, rather than other GHGs. The most promising GGR techniques include:

  • Enhancing natural land sinks (Box 1). Increasing tree cover and improving forest management, increasing the amount of carbon stored in soil and ocean sediments, and restoring peatlands have all been suggested as GGR approaches.
  • Transferring CO2 to geological storage (Box 2). CO2 can be taken from the atmosphere, directly or via plants, and pumped into underground storage in geological formations. Studies suggesting that CO2 stored in geological formations could be secure for 100,000 years. 

Key points in this POSTnote include:

  • It may be difficult to achieve net zero emissions in the second half of the century without Greenhouse Gas Removal (GGR) from the atmosphere.
  • If successfully developed, some unproven GGR techniques, such as Bioenergy with Carbon Capture and Storage (BECCS), could be employed earlier to help meet carbon targets cost-effectively.
  • However, there is risk of relying on as yet unproven GGR techniques to meet future carbon targets. Uncertainties include their scalability, effects on land use, financial viability and social acceptability.
  • There is little policy on GGR. Future policies could support the development or deployment of GGRs or their integration into emissions accounting frameworks.

Acknowledgements

POSTnotes are based on literature reviews and interviews with a range of stakeholders and are externally peer reviewed. POST would like to thank interviewees and peer reviewers for kindly giving up their time during the preparation of this briefing, including:

  • Professor Kevin Anderson, Tyndall Centre for Climate Change, University of Manchester

  • Mike Childs, Friends of the Earth*

  • Almuth Ernsting, Biofuelwatch

  • Dr Clair Gough, Tyndall Centre for Climate Change, University of Manchester*

  • Alexandra Jenkins, DfT

  • Cathy Johnson, BEIS*

  • Beth O'Connell, BEIS*

  • John Lanchbery, RSPB

  • Lord Oxburgh, House of Lords*

  • Dr Glen Peters, Centre for International Climate and Environmental Research Oslo (CICERO)*

  • Professor Pete Smith, University of Aberdeen*

  • Dr Steve Smith, CCC*

  • Owain Tucker, Shell*

  • Matt Willey & Jens Wolf, Drax*

  • Dr Phil Williamson, NERC, University of East Anglia*

*Denotes people who acted as external reviewers of the briefing

POSTnotes POST-PN-0549

Authors: Jonathan Wentworth; William Miller

Topics: Climate change, Renewable energy

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The Parliamentary Office of Science and Technology produces independent, balanced and accessible briefings on public policy issues related to science and technology.