Sensitivity of carbon budgets to permafrost carbon feedbacks and non-CO2 forcings. (25th November 2015)

• Record Type: Journal Article
• Authors: MacDougall, Andrew H; Zickfeld, Kirsten; Knutti, Reto; Matthews, H Damon
• Is Part Of: Environmental research letters. Volume 10:Number 12(2015:Dec.)
• Publication Date: 2015-11-25
• Subjects: carbon budget -- TCRE -- climate change; Environmental sciences -- Periodicals; Human ecology -- Research -- Periodicals; Environmental health -- Periodicals; 333.7
• DOI: 10.1088/1748-9326/10/12/125003
• Languages: English
• ISSNs: 1748-9326

Abstract

Abstract: The near proportionality between cumulative CO2 emissions and change in near surface temperature can be used to define a carbon budget: a finite quantity of carbon that can be burned associated with a chosen 'safe' temperature change threshold. Here we evaluate the sensitivity of this carbon budget to permafrost carbon dynamics and changes in non-CO2 forcings. The carbon budget for 2.0 of warming is reduced from 1320 Pg C when considering only forcing from CO2 to 810 Pg C when considering permafrost carbon feedbacks as well as other anthropogenic contributions to climate change. We also examined net carbon budgets following an overshoot of and return to a warming target. That is, the net cumulative CO2 emissions at the point in time a warming target is restored following artificial removal of CO2 from the atmosphere to cool the climate back to a chosen temperature target. These overshoot net carbon budgets are consistently smaller than the conventional carbon budgets. Overall carbon budgets persist as a robust and simple conceptual framework to relate the principle cause of climate change to the impacts of climate change.