Abstract
In the aftermath of the Paris Agreement, the climate science and policy communities are beginning to assess the feasibility and potential benefits of limiting global warming to 1.5 °C or 2 °C above preindustrial. Understanding the dependence of the magnitude and duration of possible temporary exceedance (i.e., “overshoot”) of temperature targets on sustainable energy decarbonization futures and carbon dioxide (CO2) removal rates will be an important contribution to this policy discussion. Drawing upon results from the mitigation literature and the IPCC Working Group 3 (WG3) scenario database, we examine the global mean temperature implications of differing, independent pathways for the decarbonization of global energy supply and the implementation of negative emissions technologies. We find that within the scope of scenarios broadly-consistent with the WG3 database, the magnitude of temperature overshoot is more sensitive to the rate of decarbonization. However, limiting the duration of overshoot to less than two centuries requires ambitious deployment of both decarbonization and negative emissions technology. The dependencies of temperature target overshoot’s properties upon currently untested negative emissions technologies suggests that it will be important to consider how climate impacts depend on both the magnitude and duration of overshoot, not just long term residual warming.
Highlights
In the aftermath of the Paris Agreement, the climate science and policy communities are beginning to assess the feasibility and potential benefits of limiting global warming to 1.5 °C or 2 °C above preindustrial
Drawing upon results from the mitigation literature and the Intergovernmental Panel on Climate Change (IPCC) Working Group 3 (WG3) scenario database, we examine the global mean temperature implications of differing, independent pathways for the decarbonization of global energy supply and the implementation of negative emissions technologies
In the range of futures explored in the WG3 scenario database, under a mid-range climate response overshoot is a virtual certainty in most pathways to achieving a 1.5 °C temperature target by the end of the 22nd century
Summary
In the aftermath of the Paris Agreement, the climate science and policy communities are beginning to assess the feasibility and potential benefits of limiting global warming to 1.5 °C or 2 °C above preindustrial. The dependencies of temperature target overshoot’s properties upon currently untested negative emissions technologies suggests that it will be important to consider how climate impacts depend on both the magnitude and duration of overshoot, not just long term residual warming. Integrated assessments of climate policy typically only consider bioenergy with carbon capture and storage (BECCS) – which is both a decarbonization and negative emissions technology— and land use change (e.g., reforestation) as possible negative emissions sources[3,4]. In the case of BECCS and other biological or biogeochemical approaches to capturing carbon, there exist uncertain, but hard, biophysical limits on the maximum deployment of negative emissions such as land and water availability[6], as well as considerable uncertainty on future policy commitment to development and deployment[7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
