CO2 removal should be limited to safe and sustainable measures

wet forestClick to enlarge
Forests & wetlands sequester CO2 in a natural way, technologies like ocean fertilization bear risks.
Source: FredanFoto /

The Paris Agreement set the international goal of limiting global warming to 1.5°C. To achieve this, it is essential to rapidly reduce greenhouse gas emissions towards zero. Additional measures are needed to remove CO2 from the atmosphere, such as reforestation. However, UBA advises against betting on untried, risky technologies.

Limiting global warming to 1.5°C will only be possible if human induced CO2 emissions are reduced to net-zero by around 2050 – in particular by phasing out fossil energy sources, such as coal and oil.  

CO2 removal measures can by no means replace decarbonisation, yet they are a necessary supplement. Well suited for this are sustainable land use measures, such as soil carbon sequestration in agricultural soils, protection and restoration of wetlands and grasslands as well as reforestation. Such measures can remove CO2 in an ecologically, socially and economically sustainable manner. UBA therefore supports sustainable land use measures as an approach to Carbon Dioxide Removal and sees an urgent need to create appropriate framework conditions, e.g. provision of financial support, technology transfer and capacity building by developed countries.

However UBA considers it risky to rely on partly unexplored and untested CO2 removal and storage technologies. Current state of knowledge suggests most CDR technologies encompass potential risks for sustainable development and the environment. For example, Ocean Fertilization, intended to enhance CO2-sequestration in algae, could over-fertilize and damage marine ecosystems. A further approach is Bioenergy Carbon Capture and Storage (BECCS), relying on industrial style plantations to provide biomass for energetic use and capturing and storing the resulting CO2 emissions from the burning process. The large scale implementation of BECCS increases competition with food production and other land uses, due to the required large areas of biomass production. It also can have negative impacts on ecosystems, water supply as well as soil and water quality. Depending on the site selection, storage of CO2 can also pose risks, such as acidification of ground water or generating local seismic activity. 

Further information can be found in the “UBA Position on Carbon Dioxide Removal”.