The Atlantic thermohaline circulation (THC) is an important component in the climate system because it strongly influences conditions in the North Atlantic region. Most climate models simulate a reduction of the THC in response to global warming, some even a complete and potentially irreversible shutdown. To avoid such irreversible climate changes, one may design climate policies that curb greenhouse gas emissions to levels preventing a THC collapse. To evaluate such mitigation policies, we use a slightly enhanced version (E-MERGE) of the MERGE model of Manne, Mendelsohn and Richels, where the climate module’s parameters have been revised with the latest findings of the Intergovernmental Panel on Climate Change. Depending on the assumed climate sensitivity, our analysis shows that preserving the THC may require in particular a strong carbon dioxide emission reduction from todays level.