Geoengineering is usually defined as the deliberate large-scale intervention in the climate system of the Earth with the purpose of mitigating the worst consequences of global warming. Understandably, this activates deep anxieties about technology in a lot of people, since it involves a radical level of interference with what we think of as “nature.” Although the earliest recorded instance of a scheme to mitigate climate change dates from 1965, during the Johnson administration, geoengineering proposals have become more frequent in the last two decades, as predictions from climate scientists have grown increasingly alarming.
Ideally, climate change would be solved by a significant, coordinated worldwide reduction in carbon emissions. However, even achieving emission reductions that are well below what’s needed to avert catastrophic changes has so far proven politically impracticable, due among other factors to the huge economic toll such measures would take, and the diversity of competing national interests. Additionally, every year that passes without concrete action on the climate makes the reduction measures required more aggressive, and therefore even harder to implement. As a consequence, interest in geoengineering has kept growing. A search of the term in the CU Boulder library website lists over fourteen thousand journal articles.
In terms of general schemes, there are two particularly active subfields in the discipline: one attempts to reduce the concentration of carbon dioxide in the Earth’s atmosphere, either through natural or artificial means such as depositing iron in the oceans to stimulate algae growth, while the other aims to manage the amount of solar radiation that the atmosphere allows to pass by, for instance, stimulating the formation of stratocumulus clouds over the subtropical ocean. This and similar ideas would increase the percentage of solar radiation reflected by the Earth, which would have the result of lowering the average temperature of the planet.
As I mentioned above, there is no shortage of reasons to oppose geoengineering. Some of them are ethical: there is a problematic aspect to thinking that we have the right to alter the climate for generations that will have no say in our decision, but will be forced to live with the results of our actions. At the same time, it seems more problematic to prioritize the needs of people who might exist over those of people who do exist, especially given that the former group may not get to exist at all if humanity continues its current trajectory. There are also pragmatic reasons: climate is the paradigmatic complex system, and the idea that we could alter it in such a radical way without producing unexpected effects is simply delusional. The problem with this objection is that, were we to actually take it seriously, it would be utterly paralyzing, since uncertainty about the more causally distant consequences of our acts is inherent to any action we perform.
Yet another common objection when projects such as these are discussed revolves around the ostensible responsibility of technology in the series of environmental disasters we are experiencing. Wouldn’t it then be absurd to think that following the same course of action—only more intensely—would have a different result? What is needed, according to these critics, is less technology, not more (technology in these critiques acting as a stand in for modern technocapitalism). I counter that there are at least two problems with this line of criticism: the first is that it ignores the centrality of technology in every human culture, while simultaneously erasing the possibility of distinguishing between different technologies by judging their effects. The second problem is that significant evidence exists of several agrarian cultures that experienced societal collapse due to resource depletion and environmental degradation. That seems to have been the case of the classic Maya civilization, that collapsed between the 8th and 9th centuries, the Polynesian inhabitants of Pitcairn Island, and the Anasazi people that lived in territories that today correspond to the states of Utah, Arizona, New Mexico, and Colorado in the USA. This strongly suggests that human inability to achieve a sustainable relation with its environment is not limited to specific economic systems.
Unfortunately, while fear of geoengineering is not unreasonable—it might after all accidentally cause damages that are as great or greater than anything we have experienced so far, including continuing ocean acidification, ozone depletion, an increase in acid deposition and deleterious effects on plants—its deployment might still be unavoidable. A group of twelve climate scientists from India, Ethiopia, Kenya, Brazil and other developing nations led by Atiq Rahman, Executive Director of the Bangladesh Center for Advanced Studies, published a text in Nature in 2018 in which they declared “Solar geoengineering is fraught with risks and can never be an alternative to mitigation. But it’s unclear whether the risks of solar geoengineering are greater than the risks of breaking the 1.5 °C warming target. As things stand, politicians will face this dismal dilemma within a couple of decades.” And former Chief Scientific Advisor for the British Government, John King, is more emphatic: “Time is no longer on our side [...] It’s certainly critically important to have deep and rapid emissions reductions, but there’s too much in the atmosphere today. As we move forward, we have to take on the concept of switching out fossil fuels entirely, but it is critically important to research removing emissions from the atmosphere in order to meet net-zero emissions.”
If the Nature signatories and King are correct, a particularly problematic aspect that will require immediate consideration is that, unlike action on carbon emissions reduction, which depends upon the formation of overarching consensus to be implemented, geoengineering technologies can be tested and put into practice by individual actors who don’t even have to be nation-states. The effects of the technology are global, but the people behind it might decide to bypass global—and even national—institutions. This greatly increases the chances of action on the issue, but also the likelihood of chaos and conflict as a result. Avoiding outcomes of this sort is going to be one of the great geopolitical challenges of the century.
 For an excellent discussion of how the concept of nature and its relationship with the human affects conversations about the environment, see Vogel 2015.
 Restoring the Quality of Our Environment. Report of the Environmental Pollution Panel President’s Science Advisory Committee (The White House, 1965)
 https://ucblibraries.summon.serialssolutions.com#!/search?ho=t&l=en&q=geoengineering. Last accessed 9/25/2020.
 This was first proposed by Paul Cruzen in his paper “Albedo enhancement by stratospheric sulfur injections: A contribution to resolve a policy dilemma?” (Crutzen 2006).
 (Robock 2008).
 This is the position of a not insignificant group of philosophers and political theorists (Elliot 1989, McKinnon 2019, Reichenbach 1992). They hold that future persons have rights which include access to a clean environment. Space prevents us from developing our views on this matter in the present text, so we’ll simply state that we do not find their arguments persuasive. For a criticism of the idea of the rights of future persons, see De George 1979 and Parfit 1987.
 See for instance Klein 2015.
 Some authors, in fact, go as far as to claim that technology had an essential role in the emergence of the very sphere of the human, and that the two are co-constitutive (Stiegler 2018).
 (Diamond 2014).
 In Janssen & Scheffer 2004 it is hypothesized that the sunk-cost effect in human decision making has played a significant role in the collapse of early societies that built larger structures.
 (Robock 2008).
 (Rahman et al. 2018), last accessed 9/26/2020.
 “Sir David King: Urgent Focus Needed on Climate ‘Restoration.’” Edie.Net, https://www.edie.net/news/9/Sir-David-King--Policy-and-business-action-n.... Accessed 26 Sept. 2020
Crutzen, P.J. “Albedo enhancement by stratospheric sulfur injections: A contribution to resolve a policy dilemma?” Climatic Change, 77 (3–4), 2006, 211–219.
De George, Richard. “The Environment, Rights and Future Generations”. In Goodpaster, K. E., and K. M. Sayre, editors. Ethics and Problems of the 21st Century. University of Notre Dame Press, 1979, pp. 93-106.
Diamond, Jared. Collapse: How Societies Choose to Fail or Succeed. New York, Penguin Books, 2014.
Elliot, Robert. “The Rights of Future People.” Journal of Applied Philosophy, vol. 6, no. 2, 1989, pp. 159–70.
Janssen, Marco A., and Marten Scheffer. “Overexploitation of Renewable Resources by Ancient Societies and the Role of Sunk-Cost Effects.” Ecology and Society, vol. 9, no. 1, 2004.
Klein, Naomi. This Changes Everything: Capitalism vs. the Climate. London, Penguin Books, 2015.
McKinnon, Catriona. “Sleepwalking into Lock-in? Avoiding Wrongs to Future People in the Governance of Solar Radiation Management Research.” Environmental Politics, vol. 38, no. 3, 2019, pp. 441–59.
Parfit, Derek. Reasons and Persons. Oxford, Clarendon Press, 1987.
Rahman, A. Atiq, et al. “Developing Countries Must Lead on Solar Geoengineering Research.” Nature, vol. 556, no. 7699, 7699, Nature Publishing Group, Apr. 2018, pp. 22–24.
Reichenbach, Bruce R. “On Obligations to Future Generations.” Public Affairs Quarterly, vol. 6, no. 2, [North American Philosophical Publications, University of Illinois Press], 1992, pp. 207–25.
Robock, Alan, et al. “20 Reasons Why Geoengineering May Be a Bad Idea.” Bulletin of the Atomic Scientists, vol. 64, no. 2, May 2008, pp. 14–59.
Stiegler, Bernard. La Technique et le Temps - (I. La Faute d’Epiméthée, II. La Désorientation, III. Le Temps du Cinéma et la question du mal-être ). Fayard, 2018.
The White House, Report of the Environmental Pollution Panel President’s Science Advisory Committee. Restoring the Quality of Our Environment. Washington, 1965.
UA, “Sir David King: Urgent Focus Needed on Climate ‘Restoration.’” Edie.Net, https://www.edie.net/news/9/Sir-David-King--Policy-and-business-action-n.... Accessed 26 Sept. 2020.
Vogel, Steven. Thinking Like a Mall - Environmental Philosophy After the End of Nature. Cambridge, Mass., MIT Press, 2015.