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Reflections on the NAS Report on Solar Geoengineering Research

On 25 March 2021, the National Academy of Sciences of the United States has released a ‘Consensus Study Report’ that calls for large investments in research on solar geoengineering.

The report agrees that climate mitigation should remain central and that decarbonization should still be pursued. However, the National Academy of Sciences now calls also for a national research programme in the United States to explore the feasibility of an alternative set of entirely speculative technologies: solar geoengineering. In essence, NAS wants to explore the feasibility of spraying aerosols in the upper atmosphere to block a part of the incoming sun-light and thus ‘to cool the planet’.

This proposal is dangerous. Solar geoengineering technologies remain speculative and assume a level of understanding of the planetary system that does not exist. Numerous studies have pointed to the risks especially for developing countries and vulnerable populations if anything goes wrong with ‘hacking the climate’.

Most importantly, the governance challenges of solar geoengineering are unsurmountable in today’s global political system. Engineering the climate by aerosol injections requires global decisions on the degree of cooling – a ‘global thermostat’. Somebody would have to decide, at planetary level, on how long ‘geoengineering’ would last. And this over generations: the NAS report assumes that even ‘short term applications’ of solar geoengineering ‘may require sustained interventions lasting a half-century or more’. In other words, at least two (future) generations would have to continue the climate hack. Moreover, as confirmed in the NAS report, the regional-scale impacts of solar geoengineering ‘may vary considerably’ but the details of these varying impacts will depend on how stratospheric aerosol injection is deployed – where will which aerosol be injected? Let’s imagine: which government or institution will decide the place of deployment and the variant impacts that countries are likely to suffer? Likewise, strong mechanisms would be needed to compensate for harm in case something goes wrong. All such decisions would require powerful global institutions – which are not yet in place.

The NAS report’s vision for global governance is clear: it is the United States that should lead the way, at least for now. Other countries are invited to join, but there is no indication that the NAS authors envision to place geoengineering technology under global control with a binding veto power for those countries in the Global South that are most vulnerable. The NAS report agrees that vulnerable groups are to be consulted – but will they have a veto right? Odd new terminology is introduced by the NAS: they define the ‘Global South’ now as ‘populations from countries that have been historically underrepresented in global decision making’ – this sounds ‘woke’ but is in complete denial of the current United Nations system in which developing countries have in fact a vast majority, as sovereign nations. Consequently, the NAS report does not seem to prioritize such multilateral institutions. Quite clearly, the report submits that ‘international governance should not begin with current treaty bodies’ and that ‘attempts at international governance … must confront the reality that achieving multilateral consensus is difficult and that initial multilateral agreements are often weak’. Of course: international resistance to solar geoengineering is likely to be huge in UN bodies.

Instead, the vision of the NAS report seems to be that scientists should lead, especially US scientists. Based on that, a global network of experts could autonomously govern research. It is widely known, however – and acknowledged by the NAS report itself – that this global research community is vastly skewed in favour of a few industrialized countries. Research governance by experts is governance by the Global North, with some ‘consultation’ of others on the side. It is, as I argued earlier, a ‘rich man’s solution’.

Now enter the real players in this game: global corporations, the fossil industry, coal mining companies, the Koch brothers, oil-producing countries, Wall Street, and more broadly all countries that are unwilling to commit to massive transformations and decarbonization of their economies. Solar geoengineering will give them new hope - that the time of coal and oil is not yet over. The pipe dream that we can continue to delay peak oil for a few more decades, if only American science will come up with the planetary techno-fix – hacking the climate, putting up sun shades on planet earth, brightening the clouds, all in the interest of granting the overconsuming, wealthy societies in the Global North a bit more time to continue with economic growth, carbon addiction and resource exploitation.

Solar geoengineering is wrong. For the last few decades, solar geoengineering has been a topic for a small group of scientists, largely at elite universities in the US and the UK. Now the world has reached a tipping point: The United States National Academy of Sciences openly seeks to normalize research on hacking the climate as a legitimate part of climate mitigation. Other science communities must now step in and raise their voice. Governments must take control. Solar geoengineering must be stopped.



The sky is falling rhetoric whether it's for global warming, cooling or change and what to do about the natural ebb and flow of temperature change since time began is more fear mongering. The latest clamor for decarbonization is another foolish aim as we need CO2 for life and it's not a problem needing to be addressed. When there has been an increase in carbon throughout history, we've seen a greater increase in the ability to grow crops and see a reduction in loss of life since fewer are dying from the cold. We can't even keep our water clean and yet the 'experts' are spraying w/o public approval chemicals in the atmosphere that in part block the sun but…


Many good and interesting points made here, thanks! However, I wondered... Shouldn't we also look at it the other way round? I mean, if "we" now decide not to pursue/research Solar Geoengineering (SG), wouldn't this also be a rich men's decision? If the Global South should have a veto right on SG, should they also have the right to veto a ban on researching SG? After all, the Global South is most at risk from the impact of global warming. Playing a bit the devil's advocate, who are we in the North to withold, on moral grounds, SG to developing low-lying island states, without even having investigated whether it could help to limit sea level rise without too many other…

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