Solar geoengineering is risky but…

Professor David Keith speaks about why solar geoengineering must be researched to see if it can secure a safe climate of 1.5ºC as a high value benefit to humanity.

David Keith is the foremost expert on solar geoengineering in the world having been involved in research for over 30 years. As well as being an adviser to Bill Gates, he is also on the Scope Ex team that is planning to carry out preliminary research this year to test the viability of stratospheric aerosol injection to cool the Earth.

This research has attracted widespread criticism from many prominent environmentalists and activists who say the unknown risks of geoengineering are too great.

In this interview with climate journalist, Nick Breeze, Keith counters claims that are presented and places solar geoengineering in the context of emissions reduction and carbon dioxide removal as a viable pathway to stabilising the climate.

Whether or not governments choose to fund climate interventions like solar geoengineering or not will depend largely on public opinion. One of the most powerful things we can do as individuals to play a part in solving the crisis is to discuss these issues with our friends, family and peers.

By talking about these complex issues, we have a chance to share our thoughts and learn from each other. Hopefully then, when our thoughts and opinions are sought, we will be able to express ourselves confidently and in the best interests of all of us.


Quotes from David Keith

“Carbon dioxide removal looks easier because people aren’t looking seriously at who pays and what the environmental consequences are. I think now we will be starting to look at what deep emissions cuts looks like, we will begin to see how hard it is going to be… Carbon Dioxide Removal is not there yet, it is not happening at large scale so it is easy to imagine this technological thing that allows us to do something in the future helps. I think the moral hazard is absolutely real.”

“Solar geoengineering could be effective if you put reflective aerosols in the upper atmosphere. If it was ever done, it ought to be done in a way that was very even, north to south, south to west and technically that is doable… The evidence from all climate models and from other analogues, is that if one did it in combination with emissions cuts that the climate risk could be reduced in ways that they could not be reduced by emissions cuts alone.”

“We could, with solar geoengineering, keep temperatures under 1.5ºC with confidence and we could prevent the loss of the major ice sheets and keep the Arctic more the way it is. I think that is pretty high value thing!”

This interview was brought to you by Cambridge Climate Lecture Series and Cambridge Zero.

Nick Breeze

Nick Breeze is an independent climate change journalist based in the UK and also hosts the ‘Shaping The Future: From Pandemic To Climate Change‘ podcast.

Professor David Keith

Professor David Keith is Gordon McKay Professor of Applied Physics for Harvard University’s Paulson School of Engineering and Applied Sciences (SEAS) and Professor of Public Policy for the Harvard Kennedy School at Harvard University. He is also board member and acting chief scientist at Carbon Engineering. he is also a member of the Keutsch Group at Harvard working on SCoPEx: Stratospheric Controlled Perturbation Experiment that has gained widespread media attention.

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