BOSTON – Humanity has never faced a collective challenge as daunting as climate change. Net global greenhouse gas (GHG) emissions must be reduced to near-zero within the next three decades to give us even a fighting chance of keeping the temperatures within 2° Celsius of pre-industrial levels.
The further we exceed that threshold, the more likely we are to run into truly catastrophic scenarios. With the United States back in the Paris climate agreement, this is the time for the world to reengage with these epochal challenges.
Bill Gates’s highly respected voice is thus a welcome addition to these efforts. In his new book, How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need, Gates argues that we need more experimentation with new ideas and technological innovations if we are to find a solution.
But his push for solar geoengineering is a step in the wrong direction, because it may undermine the incentives that are needed to meet the challenge of climate change.
The idea behind solar geoengineering is simple: If we cannot limit the amount of GHGs in the atmosphere, perhaps we can block the sunlight that generates heat, for example by creating a reflective cover.
Volcanic eruptions do this naturally. Following the eruption of Mount Pinatubo in the Philippines in 1991, large amounts of sulfuric acid and dust settled into the stratosphere, temporarily reducing the amount of sunlight that the Earth received.
Over the next three years, temperatures dropped by about 0.5°C globally, and by 0.6°C in the northern hemisphere.
Many brilliant minds are now at work on solar geoengineering projects. Scientists in Harvard University’s Stratospheric Controlled Perturbation Experiment, for example, have proposed using calcium carbonate dust rather than toxic sulfate aerosols, but the overall idea is the same, and Gates himself has backed many of these technological efforts.
What could go wrong? For starters, the risks associated with solar geoengineering are as profound as the potential benefits. In addition to creating climatic instability, the Pinatubo eruption also appears to have accelerated the destruction of the ozone layer.
To have a meaningful effect on climate change, we would have to replicate that eruption’s effect on a much larger scale, inviting even greater climatic variability, including sharp temperature reductions in some parts of the world.
Because these effects would not be distributed evenly across countries and regions, we would also have to worry about increased geopolitical instability.
If a proposal has large potential benefits but also massive potential costs, the sensible thing to do is to conduct small-scale experiments into its viability – which is precisely what some Gates-backed ventures are now doing.
The problem is that small-scale experiments will not necessarily reveal the true costs, given the complexity of climate dynamics at the global level. Creating a blanket of sun-blocking cloud dust might produce one effect at a small scale, and a completely different one at a larger scale.
Moreover, even if pursued with the best intentions, geoengineering has a dark side. The more we believe in its effectiveness, the more we will reject tried-and-tested solutions such as a carbon tax and investments in renewable energy.
This is what economists call “moral hazard”: Once economic actors understand that they will not bear the costs of reckless behavior, reckless behavior becomes more likely.
In the context of fighting climate change, once governments know that there is a way to keep polluting without making the hard choices needed to avoid a disaster, they will refrain from making those choices.
Carbon taxes will be kicked down the road indefinitely, support for green research will be curtailed, and consumers will have little incentive to reduce their own carbon footprints.
This moral hazard is not just a theoretical curiosity. For example, Gates himself suggests that even if a carbon tax could be introduced in the US, solar and wind energy will not be a sufficient solution.
But such thinking could be a fatal mistake. It is easy to imagine how attractive this skepticism will sound to politicians who don’t want to pursue policies that will disrupt communities still relying on coal production.
But we should not discount the tremendous improvements in solar and wind’s cost-effectiveness. And we must not ignore how much progress could be made by combining these energy sources with advances in storage technologies.
Moral hazard isn’t confined to governments. My own research with Will Rafey of the University of California, Los Angeles finds that the pursuit of geoengineering may impede private-sector efforts to transition to clean energy.
Firms that have already begun to invest in renewables are operating on the assumption that there will be stronger climate regulations and a robust carbon-tax regime in the future.
Yet if we dangle the possibility that solar geoengineering will prevent global warming, they will start expecting a less regulation- and tax-driven response and will curtail investment accordingly.
Ultimately, there is no easy way out and no alternative to carbon taxes and renewable energy if we want to avoid a climate disaster.
This message is lost in Gates’s enthusiasm for solar geoengineering. But the longer we delay carbon taxes and the massive additional investments necessary for expanding renewable energy, the more difficult our future climate challenges will be.
Gates’s support for solar geoengineering is an expression of techno-utopianism. Technology has to be part of the solution, but will not be a magical remedy for centuries of excessive carbon emissions.
The problem with techno-utopianism is that rather than accepting the need for costly investments and cultivating grassroots solutions from diverse perspectives, it seeks to find quick fixes and then impose them on society.
As the political scientist James C. Scott has shown, this perspective produced many social disasters in the twentieth century and may do so again in its new enthusiasm for geoengineering.
One can already see the damage of techno-utopianism in fields such as artificial intelligence, where we are promised spectacular advances, but end up with large-scale algorithmic labor displacement or harmful discrimination.
This is also visible in health care, where the US spends massively – about 18% of GDP – in part owing to an emphasis on high-tech solutions rather than investments in public health, prevention, and comprehensive health insurance. The result is poor health, despite high expenditures.
Climate change poses an even bigger challenge. It is too important to be left to those promising a sweeping technological fix delivered, literally, from above.
Daron Acemoglu, Professor of Economics at MIT, is co-author (with James A. Robinson) of Why Nations Fail: The Origins of Power, Prosperity and Poverty and The Narrow Corridor: States, Societies, and the Fate of Liberty.
Copyright: Project Syndicate, 2021.