What are the Costs and Benefits of Climate Engineering? And Can We Assess Them?

Climate engineering is discussed as an alternative to the control of greenhouse gas emissions because it is perceived that there will be no sufficiently strong international agreement on effective climate policy measures and that many climate engineering technologies can be implemented at very low cost compared to emission control. We argue that the costs and benefits of climate engineering are so far essentially unknown and in many cases no adequate concept of the costs is used. Economic cost concepts are likely to show that the cost of climate engineering will be larger than currently perceived. However, many costs will be very difficult to quantify, thus making a full cost-benefit analysis essentially impossible and requiring a debate that goes beyond purely economic arguments.