Scientists say no to Solar Geoengineering

Published on
January 28, 2022

More than 60 senior climate scientists and governance scholars from around the world have launched a global initiative calling for an International Non-Use Agreement on Solar Geoengineering. Among them are scientists from Utrecht University and Wageningen University & Research. Prof Aarti Gupta, Professor of Global Environmental Governance with the Environmental Policy Group at Wageningen University & Research is one of them:

“The time has come to take a clear stance against including speculative solar geoengineering technologies as a future climate policy option. A focus on solar geoengineering is a dangerous distraction from the urgent action that we need to take today to address climate change: to reduce entrenched inequalities and align our politics to realize a just transition globally”.

The scientists argue that solar geoengineering deployment cannot be fairly governed globally and poses unacceptable risk if implemented as a future climate policy option. The group therefore calls on fellow academics, civil society organizations and concerned individuals to sign an open letter to governments, the United Nations and other actors to stop development and potential use of planetary-scale solar geoengineering technologies. The initiative draws on an academic journal article published on January 17, 2022 in WIREs Climate Change, coauthored by 16 scientists and initiators of this group. Here you can listen to Aarti Gupta on BBC radio (last 5 minutes).

Spraying aerosols in the stratosphere

The initiative for a non-use agreement mobilizes especially against the most widely debated speculative technology: the massive spraying of aerosols in the stratosphere to block a part of incoming sunlight to cool the planet. Such dangerous planetary-scale interventions cannot be governed in a globally inclusive, fair and effective manner and must therefore be banned, according to this group of scientists and governance experts.

Deployment is ungovernable

As stated by Professor Frank Biermann from Utrecht University, a leader of the call for a Non-Use Agreement on Solar Geoengineering and first author of the WIREs article, “Solar geoengineering deployment is ungovernable in a fair, democratic and effective manner. For the last few decades, solar geoengineering has been a research topic for just a small group of scientists based largely at elite universities in the US and the UK. Now other science communities and civil society must step in and raise their voice. Governments must take control. The development of solar geoengineering technologies must be stopped.”

Threat to mitigation commitments

The Open Letter also highlights that betting on solar geoengineering as a potential future solution threatens “commitments to mitigation and can disincentivize governments, businesses, and societies to do their utmost to achieve decarbonization or carbon neutrality as soon as possible. The speculative possibility of future solar geoengineering risks becoming a too powerful argument for industry lobbyists, climate denialists, and some governments to delay decarbonization policies”.

In early 2021, this was one of the reasons presented by the indigenous Saami Council and environmental NGOs to stop a balloon test for a Harvard University solar geoengineering research programme. Planned for June 2021 above indigenous territory in Sweden, the test was halted after strong civil society opposition. Such tests should be banned worldwide, the group of more than 60 experts now argues.

Immediate action for a non-use agreement is needed

The 60 leading climate scientists and governance experts also fear that without an international ban or restrictions, a few powerful countries with support from major corporations and philanthropists could engage in solar geoengineering unilaterally or in small coalitions, even when the rest of the world opposes such deployment − or has not yet had the time to assess it and its potential dangers. This threat, the group argues, requires immediate action by governments and the United Nations for an International Non-Use Agreement on Solar Geoengineering.

More precisely, the Open Letter calls upon governments to support five core prohibitions and measures to:

  • Prohibit their national funding agencies from supporting the development of technologies for solar geoengineering, domestically and through international institutions.
  • Ban outdoor experiments of solar geoengineering technologies in areas under their jurisdiction.
  • Refuse patent rights for technologies for solar geoengineering, including supporting technologies such as for the retrofitting of airplanes for aerosol injections.
  • Not deploy technologies for solar geoengineering if developed by third parties.
  • Object to future institutionalization of planetary solar geoengineering as a policy option in relevant international institutions, including within assessments by the Intergovernmental Panel on Climate Change.

The initiative's website offers updated scientific information on various risks posed by solar geoengineering and its hypothetical technologies, details about the 60+ signatories, and a ‘Take Action’ button where others from academia and beyond can support the Open Letter.

What is solar geoengineering?

Solar geoengineering (known also as solar radiation modification or management) describes a set of hypothetical technologies to lower global temperatures by intervening in planetary climate systems. One widely debated approach is the massive spraying of aerosols in the stratosphere for instance via special airplanes or balloons. These tiny particles would scatter a small part of incoming sunlight back into space. Solar geoengineering is highly controversial, although some research groups have begun study programmes on stratospheric aerosol injection, including highly contested plans for outdoor experiments.