The historic Paris climate agreement ushered in a mantra for developing countries: “1.5 to stay alive.” It refers to the international goal of keeping global warming below 1.5 degrees Celsius (2.8 Fahrenheit) compared to pre-industrial times. But the world will likely cross that threshold within a decade, and global warming shows little sign of slowing.
The world is already facing natural disasters of epic proportions as temperatures rise. Heat records are regularly broken. Wildfire seasons are more extreme. Hurricane force is increasing. Due to rising sea levels, small island states and coastal areas are slowly being flooded.
The only known method that can quickly stop this temperature increase is climate technology. (It is also called geoengineering, sunlight reduction methods, or solar climate intervention.) This is a set of proposed actions to intentionally change the climate.
These actions include simulating the cooling effects of large volcanic eruptions by releasing large amounts of reflective particles into the atmosphere, or by brightening low clouds over the ocean. Both strategies would reflect a small amount of sunlight back into space to cool the planet.
However, there are many unanswered questions about the consequences of deliberately changing the climate, and there is no consensus on whether it is a good idea to find out.
One of the biggest concerns for many countries when it comes to climate change is national security. That doesn’t just mean wars. Risks to food, energy and water supplies are national security issues, as is climate-induced migration.
Could climate engineering help reduce national security risks from climate change, or would it just make things worse? Answering that question isn’t easy, but researchers who study climate change and national security as we do have some idea of the risks that lie ahead.
The enormous problem of climate change
To understand what climate engineering might look like in the future, we must first discuss why a country would want to try it.
Since the Industrial Revolution, humans have released approximately 1.74 trillion tons of carbon dioxide into the atmosphere, much of it from burning fossil fuels. That carbon dioxide traps heat and warms the planet.
One of the most important things we can do is prevent carbon from entering the atmosphere. But that won’t improve the situation quickly, because carbon remains in the atmosphere for centuries. Reducing emissions will ensure that the situation does not get worse.
Countries could pull carbon dioxide from the atmosphere and trap it, a process called carbon dioxide removal. Currently, carbon dioxide removal projects, including tree growing and direct air capture devices, remove approximately 2 billion tons of carbon dioxide from the atmosphere per year.
However, humans currently release more than 37 billion tons of carbon dioxide into the atmosphere each year through fossil fuel use and industry. As long as the amount added exceeds the amount removed, droughts, floods, hurricanes, heat waves, and sea level rise, among countless other impacts of climate change, will continue to worsen.
It could take a long time for emissions to reach “net zero,” the point at which humans stop increasing the concentrations of greenhouse gases in the atmosphere. Climate technology could help in the meantime.
Who could try climate technology, and how?
Several government research departments are already playing out scenarios, looking at who might decide to implement climate engineering and how.
Climate engineering is expected to be cheap relative to the cost of ending greenhouse gas emissions. But it would still cost billions of dollars and take years to develop and build a fleet of aircraft capable of transporting megatons of reflective particles into the stratosphere annually. Any billionaire considering such a venture would quickly run out of money, despite what science fiction might suggest.
However, a single country or a coalition of countries witnessing the damage of climate change could make a cost and geopolitical calculation and decide to embark on climate engineering on their own.
This is the so-called “free driver” problem, which means that one country with at least average prosperity could unilaterally influence the world’s climate.
For example, countries experiencing increasingly dangerous heat waves may want to provide cooling, or countries dependent on monsoon precipitation may want to restore some degree of reliability disrupted by climate change. Australia is currently investigating the feasibility of rapidly cooling the Great Barrier Reef to prevent its demise.
Creating risks for neighbors raises conflict alarms
The climate does not respect national borders. A climate engineering project in one country is therefore likely to influence temperatures and rainfall in neighboring countries. That can be good or bad for crops, water supplies and flood risk. It can also have widespread unintended consequences.
Some research shows that a modest amount of climate engineering would likely have widespread benefits compared to climate change. But not every country would be affected in the same way.
Once climate engineering is deployed, countries are more likely to blame climate engineering for extreme events such as hurricanes, floods and droughts, regardless of the evidence.
Climate engineering can cause conflicts between countries, leading to sanctions and demands for compensation. Climate change can make the poorest regions most vulnerable to damage, and climate engineering should not worsen that damage. Some countries would benefit from climate engineering and thus be more resilient to geopolitical conflict, and some would be harmed and thus remain more vulnerable.
No one has yet carried out large-scale climate engineering, which means that much information about its effects depends on climate models. But while these models are excellent tools for studying the climate system, they are not good at answering questions about geopolitics and conflict. Furthermore, the physical effects of climate engineering depend on who is doing it and what they are doing.
What’s next?
For the time being, there are more questions about climate technology than answers. It is difficult to say whether climate technology would lead to more conflicts, or whether it could defuse international tensions by reducing climate change.
But international decisions on climate engineering are likely to come soon. At the United Nations Environment Assembly in March 2024, African countries called for a moratorium on climate engineering, urging all precautions. Other countries, including the United States, pushed for a formal scientific group to study the risks and benefits before making any decisions.
Climate engineering could be part of a just solution to climate change. But it also brings risks. Simply put, climate engineering is a technology that cannot be ignored, but more research is needed so that policymakers can make informed decisions.
This article is republished from The Conversation, an independent nonprofit organization providing facts and analysis to help you understand our complex world.
It was written by: Ben Kravitz, Indiana University and Tyler Felgenhauer, Duke University.
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Ben Kravitz receives funding relevant to this work from the National Oceanographic and Atmospheric Administration and the National Science Foundation.
Tyler Felgenhauer receives funding relevant to this work from the National Science Foundation and from Resources for the Future.