Full Title: Mitigation and Adaptation Emissions Embedded in the Broader Climate Transition
Author(s): Corey Lesk, Denes Csala, Robin Hasse, and Radley M. Horton
Publisher(s): Proceedings of the National Academy of Sciences
Publication Date: November 21, 2022
Full Text: Download Resource
Climate change necessitates a global effort to reduce greenhouse gas emissions while adapting to increased climate risks. This broader climate transition will involve large-scale global interventions including renewable energy deployment, coastal protection and retreat, and enhanced space cooling, all of which will result in CO2emissions from energy and materials use. Yet, the magnitude of the emissions embedded in these interventions remains unconstrained, opening the potential for under accounting of emissions and conflicts or synergies between mitigation and adaptation goals. Here, we use a suite of models to estimate the CO2emissions embedded in the broader climate transition. For a gradual decarbonization pathway limiting warming to 2°C, selected adaptation-related interventions will emit∼1.3 GtCO2through 2100, while emissions from energy used to deploy renewable capacity are much larger at∼95 GtCO2. Together, these emissions are equivalent to over 2 y of current global emissions and8.3% of the remaining carbon budget for 2°C. Total embedded transition emissions are reduced by∼80% to 21.2 GtCO2under a rapid pathway limiting warming to1.5°C. However, they roughly double to 185 GtCO2under a delayed pathway consistent with current policies (2.7°C warming by 2100), mainly because a slower transition relies more on fossil fuel energy. Our results provide a holistic assessment of carbon emissions from the transition itself and suggest that these emissions can be minimized through more ambitious energy decarbonization. We argue that the emissions from mitigation, but likely much less so from adaptation, are of sufficient magnitude to merit greater consideration in climate science and policy.