Breaking Down Climate Geoengineering Part 1

Part 2: Ocean Carbon Dioxide Removal
Part 3: Solar Radiation Modification
Part 4: Considering Ethics, Equity, and Justice

The planet is getting closer and closer to exceeding the global climate target of limiting planet-wide warming by 2℃. Because of this, there has been an increased focus on climate geoengineering, with carbon dioxide removal methods included in a majority of IPCC scenarios.

Let’s Back Up: What is Climate Geoengineering?

Climate geoengineering is the intentional interaction of humans with the Earth’s climate in an attempt to reverse, stall, or mitigate the impacts of climate change. Also known as climate intervention or climate engineering, climate geoengineering attempts to decrease global temperatures through solar radiation modification or reduce atmospheric carbon dioxide (CO2) by capturing and storing CO2 in the ocean or on land.

Climate geoengineering should only be considered in addition to emissions reduction plans – not as a sole fix to the climate change crisis. The number one way to combat climate change is to reduce emissions of carbon and other greenhouse gases or GHGs, including methane.

The urgency around the climate crisis has led to research and action on climate geoengineering – even without effective guiding governance.

Climate geoengineering projects will have long-term effects on the planet, and require a scientific and ethical code of conduct. These projects will affect the land, ocean, air, and all who depend on these resources.

Rushing toward climate geoengineering methods without foresight could cause unintended and irreversible harm to global ecosystems. In some cases, climate geoengineering projects may turn a profit regardless of a project’s success (for example by selling credits to unproven and unpermitted projects without social license), creating incentives that may not align with global climate targets. As the global community investigates climate geoengineering projects, incorporating and addressing stakeholder concerns along the process needs to be placed at the forefront.

The unknowns and potential unintended consequences of climate geoengineering projects stress the need for transparency and accountability. Since many of these projects are global in scope, they need to be monitored and achieve verifiable positive impact while balancing scalability with cost – to ensure equity and access.

Currently, many projects are in the experimental phase, and models need verification before large-scale implementation to minimize unknowns and unintended consequences. Ocean experimentation and studies on climate geoengineering projects have been limited due to difficulties with monitoring and verification of the success of projects like the rate and permanence of carbon dioxide removal. Developing a code of conduct and standards is crucial for equitable solutions to the climate crisis, prioritizing environmental justice and protection of natural resources.

Climate geoengineering projects can be broken down into two main categories.

These categories are carbon dioxide removal (CDR) and solar radiation modification (SRM, also called solar radiation management or solar geoengineering). CDR focuses on climate change and global warming from a greenhouse gas (GHG) perspective. Projects look for ways to reduce the carbon dioxide currently in the atmosphere and store it in places like plant matter, rock formations, or soil through natural and engineered processes. These projects can be separated into ocean-based CDR (sometimes called marine or mCDR) and land-based CDR, depending on the materials used and the location of the carbon dioxide storage.

Check out the second blog in this series: Trapped in the Big Blue: Ocean Carbon Dioxide Removal for a rundown of proposed ocean CDR projects.

SRM targets global warming from a heat and solar radiation perspective. SRM projects look to manage how the sun interacts with the earth by reflecting or releasing sunlight. Projects aim to decrease the amount of sunlight that enters the atmosphere, consequently decreasing the surface temperature.

Check out the third blog in this series: Planetary Sunscreen: Solar Radiation Modification to learn more about proposed SRM projects.

In the subsequent blogs in this series, we will sort climate geoengineering projects into three categories, classifying each project as “natural,” “enhanced natural,” or “mechanical and chemical”.

If paired with limiting greenhouse gas emissions, climate geoengineering projects have the potential to help the global community mitigate the impacts of climate change. However, the unintended consequences of long-term climate modification remain unknown and have the potential to threaten our planet’s ecosystems and the way we, as Earth’s stakeholders, interact with the planet. The final blog in this series, Climate Geoengineering and Our Ocean: Considering Ethics, Equity, and Justice, highlights areas where equity and justice have been centered in this conversation in TOF’s past work, and where these conversations need to continue as we work toward a globally understood and accepted scientific code of conduct for climate geoengineering projects.

Science and justice are intertwined in the climate crisis and are best viewed in tandem. This new area of study needs to be guided by a code of conduct that uplifts the concerns of all stakeholders to find an equitable path forward. 

Climate geoengineering makes enticing promises, but poses real threats if we don’t consider its long-term impacts, verifiability, scalability, and equity.

Key Terms

Natural Climate Geoengineering: Natural projects (nature-based solutions or NbS) rely on ecosystem-based processes and functions that occur with limited or no human intervention. Such intervention is usually limited to afforestation, restoration or conservation of ecosystems.

Enhanced Natural Climate Geoengineering: Enhanced natural projects rely on ecosystem-based processes and functions, but are bolstered by designed and regular human intervention to increase the ability of the natural system to draw down carbon dioxide or modify sunlight, like pumping nutrients into the sea to force algal blooms that will take up carbon.

Mechanical and Chemical Climate Geoengineering: Mechanical and chemical geoengineered projects rely on human intervention and technology. These projects use physical or chemical processes to effect the desired change.