greenhouse gas removal

To stabilise global temperatures, we need to achieve Net Zero – counteracting any remaining emissions of greenhouse gases into the atmosphere with an equivalent amount of Greenhouse Gas Removal (GGR). In order to cap the rise in global temperatures at 1.5°C above the pre-Industrial level it will be necessary to achieve Global Net Zero by 2050. This means that for every tonne of carbon dioxide that is emitted into the atmosphere in that year there will need to be a tonne of carbon dioxide permanently removed from the atmosphere. 

GGR (also known as negative emissions) encompasses a wide range of proposed techniques to remove greenhouse gases from the atmosphere. While there are some proposed methods for removing greenhouse gases other than CO2, the vast majority of GGR methods involve the removal of CO2 from the atmosphere and its long-term storage so that it doesn’t find its way back into the atmosphere. 

The range of proposed GGR techniques includes biological approaches, such as planting trees and increasing the amount of carbon stored in the soil, and engineered approaches, such as enhancing the rate at which certain minerals weather and devices that directly capture CO2 from the air. To assess how effective such techniques could be, it is necessary to understand how long-lasting the storage of CO2 away from the atmosphere is and to determine the social acceptability of deploying such techniques at scale. 

To achieve the ambition of the Paris Agreement will require GGR techniques to be deployed at a vast scale. The exact amount of GGR required will depend on what the temperature goal is (more GGR will be required to achieve the 1.5°C goal than a 2°C goal), the rate of emissions reduction (the quicker we reduce emissions, the less GGR will be required to counter the remaining emissions) and climate sensitivity (more GGR will be required if the climate is more sensitive to increases in the amount of greenhouse gases in the atmosphere). Current estimates are that between 400-1600 billion tonnes of CO2 will need to be removed from the atmosphere during the course of the century. 

There is a need to demonstrate whether proposed GGR techniques are effective and socially acceptable at a significant scale. This will require resources to research and develop proposed techniques, along with detailed consideration of the regulatory frameworks that need to be put in place to appropriately incentivise deployment. 

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