Negative emissions physically needed to keep global warming below 2 °C.

Area of Science:

• Climate Science
• Environmental Science
• Carbon Cycle Research

Background:

• Global warming necessitates limiting atmospheric CO2 concentrations to below 2°C.
• Two primary strategies exist: conventional mitigation (reducing CO2 production) and negative emissions (capturing atmospheric CO2).

Purpose of the Study:

• To quantify the trade-off between conventional mitigation and negative emissions under the RCP2.6 scenario.
• To assess the required scale of negative emissions and storage capacity for achieving the 2°C target.

Main Methods:

• Utilized state-of-the-art carbon-climate models.
• Analyzed the Representative Concentration Pathway 2.6 (RCP2.6) scenario.
• Quantified the range of required negative emissions and storage capacity under varying mitigation assumptions.

Main Results:

• In a best-case scenario, 0.5-3 Gt C/year of negative emissions and 50-250 Gt C of storage are needed.
• In a worst-case scenario, 7-11 Gt C/year of negative emissions and 1,000-1,600 Gt C of storage are required.
• The feasibility of these scales for negative emissions is uncertain.

Conclusions:

• Accelerated development of negative emission technologies is crucial.
• Conventional mitigation must remain a substantial component of climate policy to meet the 2°C target.
• The study underscores the significant challenge of achieving climate targets without a dual approach.