Following the entry into force of the Paris Agreement in November 2016, governments around the world are now expected to turn their nationally determined contributions into concrete climate policies. Given the global public good nature of climate change mitigation and the important cross-country differences in marginal abatement costs, distributing mitigation efforts across countries could substantially lower the overall cost of implementing climate policy. However, abating emissions abroad instead of domestically may face important political and popular resistance. We ran a lab experiment with more than 300 participants and asked them to choose between a domestic and an international reforestation project. We tested the effect of three informational treatments on the allocation of participants’ endowment between the domestic and the international project. The treatments consisted in: (1) making more salient the cost-effectiveness gains associated with offsetting carbon abroad; (2) providing guarantees on the reliability of reforestation programmes; (3) stressing local ancillary benefits associated with domestic offset projects. We found that stressing the cost-effectiveness of the reforestation programme abroad did increase its support, the economic argument in favour of offsetting abroad being otherwise overlooked by participants. We relate this finding to the recent literature on the drivers of public support for climate policies, generally pointing to a gap between people's preferences and economists’ prescriptions.