What is geoengineering?

Geoengineering proposals aim to intentionally manipulate the Earth's climate at large scales and have been suggested as a possible response to climate change.

A wide range of geoengineering proposals have been suggested, although most would need further, and often substantial, development before they would reach an operational stage. The potential consequences of geoengineering are significant. Beyond questions of whether a geoengineering proposal would be effective in changing the climate as intended, it is crucial that issues including safety, ethics and public opinion are also accounted for.

Geoengineering proposals can largely be divided into two groups:

Solar geoengineering proposals aim to cool the Earth by reflecting more of the Sun's warming radiation back to space.

Examples of solar geoengineering proposals include:

• forming reflective particles in the stratosphere
• increasing the reflectivity of low level marine clouds
• altering crops to make them more reflective

Carbon dioxide geoengineering proposals aim to cool the Earth by removing the greenhouse gas carbon dioxide (CO₂) from the atmosphere.

Examples of carbon dioxide geoengineering proposals include:

• Capturing CO₂ directly from the air and storing it underground
• Fertilising the ocean to increase CO₂ uptake
• Large scale afforestation

You can read more about geoengineering in IAGP member Nem Vaughan's 'Geoengineering Explainer' for The Guardian newspaper.

Further information on geoengineering:

• The Royal Society's Report: 'Geoengineering the Climate: Science, Governance and Uncertainty' - an excellent broad introduction to the area of geoengineering

• Kiel University's Climate Engineering News Round-up - provides an up-to-date summary of proceedings in the field of geoengineering

• "Engineering the climate?" - a short animated film aimed at a younger audience (via EuTRACE)
• NERC's Study: 'Public dialogue on geoengineering'
• The Geoengineering Model Intercomparison project (GeoMIP)
• The Oxford Martin School's Geoengineering Programme
• The Royal Society's Report: 'Solar Radiation Management Governance Initiative (SRMGI)'
• U.S. Government Accountability Office's Report: 'Climate Change: A coordinated strategy could focus federal geoengineering research and inform governance efforts'