Emissions corridors preserving the Atlantic ocean thermohaline circulation

• Main Author: K. Zickfeld
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: climate change; tolerable windows approach; emissions corridors; sensitivity analysis; The Corridor; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.530.2783; http://www.iet.tu-berlin.de/~bruckner/Publications/zickfeld_lugano02.pdf

The Atlantic thermohaline circulation (THC) transports large amounts of heat northward, acting as a heating system for the northern North Atlantic and north-western Europe. Paleo-reconstructions and a large number of model simulations have shown the THC to be stable only within certain limits beyond which the circu-lation shuts down. In this paper we derive emission corridors for the 21 century preserving the Atlantic thermohaline circulation. To this end a multi-gas reduced-form climate model has been coupled to a dynamic four-box model of the Atlantic thermohaline circulation. Both models allow for the relevant uncertainties (i.e., climate and hydrological sensitivity) to be taken into account. The emission corridors are calculated along the conceptual and methodological lines of the tolerable windows approach. The corridor boundaries demarcate time-dependent limits beyond which either the THC collapses or the mitigation burden to avoid such an event becomes intolerable. Accordingly, the corridors represent the maneuvering space for any climate policy com-mitted to preserve the THC without endangering future economic growth. Results show a large dependence of the width of the emission corridors on hydrological sensitivity, which is a measure for the amount of additional freshwater entering the North Atlantic, and on climate sensitivity.