Greenhouse Gas Removal (GGR) is also known as ‘negative emissions’, or in the case of carbon dioxide (CO₂) specifically, ‘carbon dioxide removal (CDR)’. It is an umbrella term for techniques that capture greenhouse gases from the air and store or chemically convert them with some degree of permanence. Unlike techniques to reduce emissions, which prevent greenhouse gases from entering the air, GGR techniques take back greenhouse gases that are there already.

There is a wide variety of approaches and methods for GGR, but they have two stages in common: a stage of capturing the greenhouse gas and a stage of storing or converting it.

For CO₂ capture, it can happen through biological processes, industrial chemical processes, or rock weathering processes. Depending on the technique, the carbon can be stored in trees, plant matter, in the soil, deep underground, in the oceans, or in long-lived products.

Interest in GGR is rising rapidly in response to the urgent need to achieve net-zero emissions. Some GGR techniques have been around for a long time, such as planting trees and biochar. But most are new technologies that are starting to emerge around the world.