While the past few years have seen tremendous accomplishments in the fight against climate change, projections for changes in global temperature continue to be dire. Even if every country fulfills its commitments under the Paris Climate Agreement, the UN Environmental Program predicts that global emissions will still lead to well more than 2 degrees Celsius of warming.
Beyond the usual solutions of focus on reducing emissions, another possibility has been put forward: climate engineering (also called “geoengineering”). This flips the dynamic of climate action on its head. Where other climate strategies avoid worsening the world’s climate, climate engineering takes active steps to reverse the causes of climate change. Scientists warn, however, that large scale changes to the global climate will invariably lead to unintended consequences, and climate engineering potentially comes with great risks.
The longer it takes to drastically draw down emissions, the more likely climate engineering is going to be required to protect society despite the risks. Acting now to build consensus around its governance will help encourage the milder, safe forms of climate engineering while discouraging the more extreme, dangerous forms.
Climate engineering can be divided into two forms, solar radiation management and carbon dioxide removal. The former focuses on reducing the amount of sunlight that gets absorbed by the earth. Some methods for this are quite mundane, such lightening the color of roads and roofs to reflect more light. Other methods are more extreme and untested, such as releasing reflective particles into the atmosphere or launching reflective satellites into orbit.
Atmospheric carbon dioxide removal can include slower but more tested methods like planting new forests and “biochar,” the creating and burying of charcoal to lock its carbon in the soil. A moderate approach is carbon capture and sequestration. One of the most extreme forms of carbon dioxide removal includes adjusting the chemical composition of the oceans to absorb carbon dioxide directly, or encouraging the growth of ocean-spanning algae that would absorb CO2.
The more extreme methods of both forms do come with significant risks. Ecosystems, and the earth’s biosphere as a whole, are incredibly complex, and it is impossible for us to know what the long-term consequences of modifying our climate, intentionally or unintentionally, will be. Changing the composition of the earth’s oceans could devastate marine life, and reducing the amount of sunlight absorbed by earth’s surface could change precipitation patterns in unexpected ways, disrupting ecosystems and agriculture around the world.
Critics also point to climate engineering’s potential to interfere with other solutions to climate change. The ability to offset substantial emissions, even when it comes with great risk, could discourage governments and industries from cutting their emissions. Climate engineering can also complicate climate diplomacy between countries by creating the potential for rogue actors. Climate change poses a large enough threat that nations could conceivably choose to implement climate engineering strategies without input or approval from their neighbors, disrupting regional rainfall and fish stocks. This could be seen as an extremely careless, potentially hostile act, and it is not known what kind of recourse affected countries could pursue. At the very least, it would severely damage international cooperation on climate change.
Creating a comprehensive international framework around climate engineering is critical to avoiding such dangers. An international body that meets regularly to discuss the implications of current technological and climate trends could decide which climate engineering methods are warranted and which ones are too risky for member states to pursue. It could also facilitate the sharing of climate engineering technology and establish protocols for nations to cooperate with their neighbors when needed.
A strong first step would be to incorporate climate engineering into the next Intergovernmental Panel on Climate Change report to build technical consensus on the issue. After that, incorporating climate engineering governance into the United Nations Framework Convention on Climate Change would be the most effective option, with the existing Warsaw Mechanism on Loss and Damage serving as a model. This would take advantage of the existing institutional infrastructure and momentum of an existing body and keep the governance for the varied forms of climate engineering consolidated in a single body.
It would be wise to establish this body within the next few years, even if its conclusion is that climate engineering beyond planting new forests and making buildings and roads more reflective should be not pursued. Currently, the prevailing opinion in the scientific community is that more aggressive forms of climate engineering are too dangerous (thought the issue is still debated). There is no actual prohibition against it, however, so formalizing the prevailing opinion as an international agreement would strengthen it.
As time goes on, technology, our understanding of climate science, and our need will all change. The sense of direction given by an international governing body will help to direct research in the directions most likely to be promising. If the decision is made to authorize more potent methods of climate engineering, the governing body would help to ensure that they are implemented as safely as possible and in a way that respects the human rights of vulnerable populations that might unduly bear the brunt of their negative impacts. Starting to develop these kinds of norms around climate engineering in the short-term will be important as these human challenges will ultimately be more challenging than the technical challenges of geoengineering.