6. Global Public Goods

Global public goods affect people all over the earth. Sandler stresses the aggregation technology of different global public goods; the mitigation of carbon dioxide is a summation public good while checking biological invasions is a weakest link public good. Simple game theory models of summation and weakest link public goods are considered. While climate change is widely perceived to be the major environmental issue for humanity, Perrings claims that biological invasions are one of the most important challenges. I consider the ingredients of a model where global change consists of climate change and linked biological invasions; the formal model is in the Appendix. A key issue in climate change is the discount rate, and Partha Dasgupta argues that if climate change is truly disastrous the discount rate could be negative, strengthening the case for acting to avoid the disaster. Chhatre and Agarwal investigated the following question: if we have an interest in sequestering carbon in the forests of developing countries, how are livelihoods likely to be affected; this involves some conceptual and empirical issues.