Carbon Sink Matrix

Developing a Quality Index for Carbon Removals: Insights from Working Group 3

Underwater landscape with trees above the water

Beside an immediate and comprehensive reduction of greenhouse gas emissions and the avoidance of emissions in future, carbon removal is postulated as a third essential element to mitigate climate change by the IPCC. Without accelerating the rollout of carbon removal, the goal of limiting global warming to 1.5 °C cannot be reached anymore (see point 8 here). Carbon removal is defined as “human activities capturing CO2 from the atmosphere and storing it durably in geological, land or ocean reservoirs, or in products” (see CDR Report). There are a variety of ways in which humans can either accelerate the natural carbon cycle, which is based on biological sequestration, or find other, technical ways to draw carbon from the atmosphere and store it. For industrial companies that want to invest in such carbon removals, it is difficult to get an overview of which technologies are useful, what possible co-benefits or undesired side effects are and at what stage of development the methods are. That is why ESTAINIUMs Working Group 3 is working on a quality index for carbon removals, aiming to achieve more transparency and easy comparability of different carbon removal types. In a first step, we compared existing estimates for costs and quantitative potentials:


The graph shows the mean values of indicated ranges for potentials and costs, especially for carbon removals with low technology readiness level (TRL) the numbers are rough estimates. A TRL below 3 stands for technologies in proof of concept or research stage. 4-6 is development phase and technologies with TRL higher 7 are gradually entering the market right now. Globally, scientists predict that up to 10 GtCO2 will need to be removed annually from the atmosphere by 2050, with increased removal capacity up to 20 GtCO2 per year by 2100) (see here). All technologies to the left of the estimated potential in the graph would be used in this case. The marginal costs (=market price for carbon removal) would then be determined by the most expensive technology still needed.

In the “further information” table you can download below, you can see the numbers behind the graph and a short description of each carbon removal type. It is important to note that the values represent global averages. This means that the costs for individual projects can vary depending on the location. Technologies to capture CO2 at point sources such as fossil power plants or industrial processes, which are usually listed under the term CCS (Carbon Capture and Storage), are not included because the source of CO2 is not the atmosphere. These technologies are therefore assigned to the category "Carbon Reduction".

In the following weeks, ESTAINIUMs Working Group 3 will discuss further indicators for comparing the quality and potential limiting factors of different carbon removal types. The target of the working group is to facilitate the decision-making process in the field of carbon removals by enhancing transparency. If you are interested in joining the discussions, please contact us on

Go back