CL3.03/BG1.24CL3.03/ BG1.24

Carbon budgets and climate-carbon response: governing mechanisms, limitations, and implications for the Paris Agreement (co-organized) 
Convener: Andrew MacDougall  | Co-conveners: Joeri Rogelj , Katarzyna Tokarska 
Carbon budgets are a finite quantity of carbon that can be emitted whilst holding warming below some given temperature level, such as the 1.5 and 2.0ºC temperature limits specified in the Paris Agreement. Carbon budgets emerge from the near-proportional relationship between total anthropogenic emissions of CO2 and change in global mean temperature seen in virtually all Earth System Models. This relationship is known as the Transient Climate Response to Cumulative CO2 Emissions (TCRE). Carbon budgets and the associated cumulative emissions framework have recently been used to: estimate the fraction of known fossil fuel reserves that can be burnt, attribute historical responsibility for climate change, and to scrutinize national emissions commitments towards meeting the Paris Agreement goal.

The session invites contributions examining a wide range of aspects related to carbon budgets and the TCRE framework, including: the governing mechanisms that lead to the emergence of TCRE, how carbon budgets are affected by previously unquantified feedbacks (e.g. permafrost carbon feedback, wetland methane feedback) and non-CO2 forcings (e.g. aerosols, non-CO2 greenhouse gases ext.), quantification of the remaining carbon budget to reach given temperature goals (for example, from the Paris Agreement), uncertainties associated with these budgets, the role of pathway dependence, and the behaviour of TCRE in response to artificial CO2 removal from the atmosphere. Contributions from the fields of climate policy and economics focused on applications of carbon budgets are also encouraged.