Dr. Thomas Ramge thinks and writes at the crossroads of technology and economics, sustainability and society. He has published more than twenty nonfiction books, selling more than two million copies worldwide, including Who’s Afraid of AI?, On the Brink of Utopia, Reinventing Capitalism in the Age of Big Data, and The Global Economy as You’ve Never Seen It. His essays and articles appear in The Economist, Harvard Business Review, MIT Sloan Management Review, and Foreign Affairs. He holds a PhD in sociology of technology and is an Associated Researcher at the Einstein Center Digital Future. His work has been translated into twenty languages and has received numerous publishing awards, including the German Essay Prize 2022, the Axiom Business Book Award 2019 (Gold Medal, Economics), and the getAbstract International Book Prize 2018.
What’s the big idea?
Earth is at a tipping point, with climate change accelerating toward catastrophic and irreversible consequences. In Dimming the Sun, award-winning science writer Thomas Ramge explores a controversial yet potentially life-saving solution: solar geoengineering. From atmospheric aerosols to solar sails, he explains how these technologies could slow global warming while examining their risks, uncertainties, and political challenges. As time runs out, Ramge argues that researching these options now may be our best chance to buy time and prevent the worst of climate change.
Below, Thomas shares five key insights from his new book, Dimming the Sun: The Urgent Case for Geoengineering. Listen to the audio version—read by Thomas himself—in the Next Big Idea App.
1. Solar geoengineering is a bad idea—whose time might come sooner than we think.
Dimming the sun is taboo in the climate policy establishment—not just the action but even the thought of it. The IPCC avoids the topic with dogmatic consistency. The climate debate is stuck in a constant loop in parliaments, international forums, talk shows, and podcasts. The tune is always: We need to decarbonize! Faster!
Yes, that is correct. We all know it. Meanwhile, temperatures continue to rise—as do emissions. The goals of the Paris Agreement are history today. It is very unlikely that we will end up in a world with less than 2.5 degrees Celsius above preindustrial levels, and possibly much higher.
Nobody knows the future. But I dare to predict that solar geoengineering will disrupt discussions and negotiations about climate policy in the coming years and steer them in a new direction. And the technology will most likely make its way into the world in the next decade—whether we want it or not. This is why I wrote this book.
2. Healthy skepticism calls for research and governance.
To avoid any misunderstandings from the get-go: I am not arguing to start geoengineering the atmosphere as soon as possible, and over my years of research, I have not come across a reasonable scientist in the field who does. But, like many of these scientists, I am troubled by the lack of open consideration on the topic. Given the facts we know today and considering the trends we see, I am convinced that solar geoengineering bears great potential to save the world from the worst effects of climate change. Dimming the sun can buy us time to transition into the post-fossil age before the climate totally freaks out.
There are many good reasons to view solar geoengineering with healthy skepticism. And critical questions are, of course, imperative when it comes to the possible use of solar geoengineering. Some typical questions of technology assessment are:
- Will the use of a new technology do significantly more good than harm?
- How would the technology have to be used to benefit many people and, ideally, harm no one?
- What incalculable risks does the use of a new technology entail?
3. Not if, but when and how…
Solar geoengineering is an urgent case. It is no longer a question of whether it will be carried out, but only when, whether planned and in cooperation with critical geopolitical actors or by rogue agents.
Dimming the sun is cheap. One could also say that it is too cheap. Maintaining the Earth’s temperature at current levels by putting sulfur aerosols in the stratosphere is expected to cost less than twenty billion dollars annually. This would save hundreds of billions in climate change costs in the short term and probably trillions in the medium term. Who might be tempted?
“Dimming the sun can buy us time to transition into the post-fossil age before the climate totally freaks out.”
Rich states or an alliance of smaller countries from the Global South that suffer particularly severely from climate change would be able to dim the sun. A tech-fanatic tycoon with the personality of Elon Musk might feel called upon to turn down the Earth’s thermostat. A radical non-profit organization with a wide-reaching enthusiastic audience could also announce that the suffering caused by climate impacts is too great—and then take independent action while claiming: “Solar radiation modification may not be a perfect solution, but it is better than none at all.”
Global geoengineering chaos is conceivable: different actors sowing clouds and dimming the sun, uncoordinated and using various methods on several continents. Climate scientists call this version “rogue geoengineering.” Obviously, that is not how it should be done. So, we must establish mechanisms and possibly new institutions to decide on, regulate, and govern solar geoengineering.
4. It’s not a solution. Just a stopgap!
The greatest risk of solar geoengineering lies not in the technology but in our human flaws—our capacity for self-deception and penchant for easy excuses. “We have a technical solution,” we might say, “so we don’t have to change our behavior.” Climate economists call this danger the “moral hazard of geoengineering.” From a game theory perspective, there is a heightened form of the free-rider effect here. Actors could benefit from geoengineering without being involved and, at the same time, continue to produce CO2 without personally feeling the consequences of their harmful behavior.
Make no mistake. Dimming the sun as an interim measure makes sense only if all parties understand that an interim solution is precisely that—an incentive to use the time gained with all their might to achieve an actual solution. If you are in a boat with a leak, it’s not enough to provisionally plug the hole if you want to sail around the world.
“Dimming the sun as an interim measure makes sense only if all parties understand that an interim solution is precisely that—an incentive to use the time gained with all their might to achieve an actual solution.”
Conventional solutions for dilemmas are, for the most part, ineffective. A pragmatic solution to reduce the “moral hazard” could look like this: As many actors as possible commit to an international agreement to understand and use geoengineering exclusively as a way to gain more time for the decarbonization process. They agree to limit the technical intervention to, say, 1.8°C of warming. At the same time, the “United Geoengineering Nations” commits to driving green energies forward faster and more consistently—which will be easier in 2040 than today, when green energy will be cheaper than fossil energy almost everywhere in the world. With abundant green energy, there is an opportunity to gradually reduce the proportion of CO2 in the atmosphere using energy-hungry extraction processes, so-called carbon dioxide removal (CDR).
5. Responsible geoengineering.
The idea of dimming the sun, in some ways, disturbs me because it conflicts so strongly with our image of what humanity should be. It throws us back to what we are: carbon junkies.
First, the human species, out of stupidity and greed, screwed up the very climate that made it possible for them to prosper. Then this species, in its self-importance, believed that it could restore the preindustrial climate by tinkering with the thermostat of the Earth system. It’s really not flattering to look in the mirror and see humanity’s irrational behavior, its callousness, and its hubris. However, allowing this fixation on our worst qualities to guide a decision about geoengineering is also useless. No matter how pessimistic one’s view of our relationship with the planet may be, it must not prevent humanity from doing better this time. To be more precise, we must finally follow the science.
Responsibility toward future generations requires us to turn climate science and geophysics into repair tools against the backdrop of climate change. For this to succeed, the participation of social sciences and economics, engineering and philosophy, political science, and law is also required. I hope that if we determine we must dim the sun to prevent climate catastrophe, we will have by then found a way to do so with minimal negative impact on the ecosphere. And I hope the decision will be made by a consensus of almost all countries. After a few decades, we may be able to cease putting sulfur in the sky, and the sun can once again shine as it has for the last one hundred thousand years. The post-fossil age has finally begun.
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