CC-21:
Implications of Carbon Cycle Feedbacks for Social Cost of Carbon

Tuesday, 17 June 2014
146B-C (Washington Convention Center)
Joseph Majkut1, Jorge L Sarmiento1,2, Thomas L Froelicher2, Michael Oppenheimer3 and Robert E Kopp III4, (1)Princeton University, Atmospheric and Oceanic Sciences, Princeton, NJ, United States, (2)Princeton Univ, Princeton, NJ, United States, (3)Princeton University, Princeton, NJ, United States, (4)Rutgers University New Brunswick, Piscataway, NJ, United States
ePoster
Abstract:
The natural sinks of anthropogenic CO2 are critical the earth system response to CO2 emissions. Currently, excess CO2 is removed from the atmosphere into the land biosphere and ocean at a rate nearly 50% that of fossil fuel emissions, which provides a significant buffer against increased climate change. However, as the climate changes, the ability of the natural CO2 sinks to continue capturing emissions is projected to decrease, which will lead to additional warming resulting in positive feedbacks that amplify the impacts of CO2 emissions. The potential magnitude of this positive climate feedback is uncertain. In this work, we discuss the effect of including the carbon cycle feedback in the integrated assessment model, DICE, using a simple parameterization of the global carbon cycle. We introduce uncertainty to show that optimal policy decisions can be strongly affected by the still-uncertain carbon cycle dynamics. Ignoring the feedbacks in the carbon cycle in policymaking leads to increased damages and a higher social cost of carbon. Uncertainty in the carbon feedbacks plays an important role and we show that measurements of the global carbon cycle made over several decades and measurement-types can be incorporated into policy decisions to facilitate learning and potentially averting trillions of dollars in additional damages due to climate change.