Could Climate Engineering Reduce National Security Risks From Climate Change?

The landmark Paris climate agreement gave rise to a rallying cry from developing nations: "1.5 to stay alive." It refers to the global target of limiting warming to below 1.5 degrees Celsius (2.8 Fahrenheit) above pre-industrial levels. Yet the planet is likely to exceed that limit within 10 years, with little evidence that global heating is easing.

As temperatures climb, the world is already experiencing natural disasters on an enormous scale. Temperature records are regularly surpassed, wildfire seasons have become more severe, hurricanes are growing more powerful, and rising seas are gradually inundating small island states and coastal regions.

Climate engineering is the only known approach that could rapidly halt this increase in temperature. Also referred to as geoengineering, sunlight reduction methods or solar climate intervention, it encompasses proposed measures intended to deliberately change the climate.

These measures include reproducing the cooling impact of major volcanic eruptions by releasing vast quantities of reflective particles into the atmosphere, or brightening low-lying clouds above the ocean. Each approach would send a small proportion of sunlight back into space, cooling the Earth.

However, deliberately changing the climate raises numerous unresolved questions, and there is no agreement on whether investigating it further is even desirable.

For many nations, national security is among the greatest climate change concerns. This involves more than armed conflict: threats to food, energy and water supplies are national security matters too, as is migration driven by climate impacts.

Could climate engineering lower the national security threats posed by climate change, or might it aggravate them? The answer is complicated. Still, researchers such as us who examine climate change and national security have some sense of the risks that may lie ahead.

The immense challenge of climate change

Before considering how climate engineering could develop, it is worth examining why a country might choose to pursue it.

Since the industrial revolution, people have released approximately 1.74 trillion tonnes of carbon dioxide into the atmosphere, principally by burning fossil fuels. This carbon dioxide retains heat and thereby warms the planet.

Stopping further carbon emissions into the atmosphere is one of the most important actions available. Yet this would not improve conditions quickly, as carbon remains in the atmosphere for centuries. Cutting emissions would simply prevent the problem from becoming worse.

Nations could remove carbon dioxide from the atmosphere and permanently store it, through a process known as carbon dioxide removal. At present, carbon dioxide removal initiatives - including tree planting and direct air-capture technologies - extract around 2 billion tonnes of carbon dioxide from the atmosphere annually.

However, fossil fuel use and industry currently add more than 37 billion tonnes of carbon dioxide to the atmosphere every year. While the quantity emitted exceeds that removed, droughts, floods, hurricanes, heatwaves and sea-level rise - alongside many other climate change effects - will continue to intensify.

Reaching "net-zero" emissions, when humans are no longer raising atmospheric greenhouse gas concentrations, may take considerable time. Climate engineering could offer help during that intervening period.

Who could pursue climate engineering, and in what way?

Several government research bodies are already modelling possible scenarios, including which actors could opt to conduct climate engineering and how they might do so.

Climate engineering is anticipated to be inexpensive compared with eliminating greenhouse gas emissions. Nevertheless, it would require billions of dollars, as well as years of development to create a fleet of aircraft capable of transporting megatonnes of reflective particles into the stratosphere each year. Despite science fiction portrayals, any billionaire attempting this alone would soon exhaust their funds.

A country, or a coalition of countries, experiencing the damage caused by climate change could instead weigh the costs and geopolitical implications, then decide to launch climate engineering independently.

This is known as the "free driver" problem: a single nation with at least moderate wealth could act alone in a way that affects the global climate.

Countries facing ever more dangerous heatwaves, for instance, might seek to induce cooling. Nations reliant on monsoon rainfall could want to recover some of the predictability that climate change has disrupted. Australia is currently assessing whether the Great Barrier Reef could be cooled rapidly enough to avert its destruction.

Risks to neighbouring countries raise the prospect of conflict

The climate does not observe national boundaries. A climate engineering project carried out by one country would therefore probably influence temperatures and rainfall in neighbouring states. This could benefit or harm crops, water resources and flood risks, while also producing far-reaching unintended effects.

Some research indicates that a moderate level of climate engineering would probably deliver broad benefits relative to climate change. Yet the consequences would not be the same for every country.

After climate engineering has been deployed, states may become more inclined to attribute extreme events - including hurricanes, floods and droughts - to it, irrespective of the evidence.

Climate engineering could trigger disputes between countries, resulting in sanctions and compensation claims. Climate change can make the poorest areas especially exposed to damage, and climate engineering must not worsen that harm. While some countries would gain from climate engineering and become more resilient to geopolitical conflict, others would be adversely affected and made more vulnerable.

No large-scale climate engineering has yet been undertaken, so much of what is known about its impacts is based on climate models. Although these models are excellent for investigating the climate system, they cannot reliably answer questions concerning geopolitics and conflict. Furthermore, the physical consequences of climate engineering would depend on who carried it out and precisely what they did.

What happens next?

At present, climate engineering produces more questions than answers. It is difficult to determine whether it would generate additional conflict or reduce international tensions by easing climate change.

International decisions on climate engineering are, however, likely to arrive soon. At the United Nations Environment Assembly in March 2024, African countries called for a moratorium on climate engineering and urged maximum precaution. Other countries, including the United States, advocated creating a formal scientific body to evaluate risks and benefits before decisions are taken.

Climate engineering may form part of a fair solution to climate change, but it also entails risks. In short, it is a technology that cannot be disregarded, though further research is required to enable policymakers to take informed decisions.

Ben Kravitz, Assistant Professor of Earth and Atmospheric Sciences, Indiana University, and Tyler Felgenhauer, Research Scientist in Civil and Environmental Engineering, Duke University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.