In this ClimateGenn episode I am speaking with Professor Raymond Pierrehumbert, who is the Halley Professor of Physics at the University of Oxford about solar geoengineering. He and Professor Michael E. Mann from Pennsylvania University coauthored an article in The Guardian on the 12th March 2025 titled:
‘The UK’s gamble on solar geoengineering is like using aspirin for cancer’.
Professor Raymond Pierrehumbert
Here we delve deeper into Ray’s overt objections to the UK’s Advanced Research & Invention Agency (ARIA). ARIA is the UK’s version of the mysterious US Defence Advanced projects Agency (DARPA). ARIA has recently allocated £45mn British Pounds to fund solar geoengineering projects including outdoor experiments.
“We shouldn’t be actively creating harm. And the first line of defence is to actually not at least have governments and philanthropy funding these outdoor experimentations.”
Professor Pierrehumbert
In the next episode I am speaking with Mike Berners-Lee about his new book, Climate Of Truth, which will be published next month.
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Below are my notes for the interview:
1. You state: The Advantaged Research & Invention Agency (ARIA) project document titled ‘Cooling the Earth’ highlights the need but not the outcome of sustained global-scale deployment of solar radiation management. Can you attempt to paint a picture of what a world with sustained deployment of such engineering would look like- what are the most worrying factors?
2. The project brief is for Small-scale trials – you cite the famous slippery slope whereby small scale becomes large-scale and then we are deploying. What if small scale teaches us that big scale wont work?
Leadership is critical –
3. A few weeks ago, Jeffrey Sachs in a webinar said in ref to SRM deployment: “the fundamental problem [is] that the world is not governed by even the most basic ethical standards of survival, decency and respect for young people and future generations.”
4. In the US there is rogue-state leadership, coupled with techno-hubris that is off the scale – isn’t a DOGE-like break-everything approach to climate engineering by the rocket men inevitable?
–Does this make the UK look like a good option to provide counter balance arguments?
5. At the COPs in recent years I have spoken with youths from West African nations, SE Asia and central America who regard SRM research as a human rights issue – they are currently on track to face existential climate impacts and the world is not making the right progress on fossil fuels. How would you say to them that you are taking this technology off the table?
– if the research indicated that the midlatitudes could be marginally cooled and save millions of lives but there was uncertainty elsewhere what would you response be?
6. In your article you write at the end that this can be stopped with rigorous pushback – can you tell us what that would look like?
7. We are clearly moving into an era where people who are experiencing and are concerned about extreme climate risk are going to be divided over what actions to take to mitigate, adapt, and even intervene – how do you see us bridging our differences to make the right decisions on existential issues like geoengineering?
– facts versus emotions versus disinformation.
