Climate change affects people all over the globe, regardless of who emits greenhouse gases and where. Since climate damages do not just affect those who generated the emissions, the social costs of greenhouse gas emissions are not fully reflected in market prices. As a consequence, the market on its own does not provide sufficient incentives for reducing emissions, for example by changing behavior or switching to cleaner technologies. Dedicated climate policies are therefore required to align the self-interest of individual actors with what is socially desirable. Likewise, since the full benefits of technological progress often do not accrue to those who deploy an innovation, policies to support emerging mitigation and adaptation technologies are also needed. The option space to implement climate policies crucially depends on how costs and benefits are distributed between different actors. The availability of mitigation and adaptation technologies is a key determinant of political feasibility. Effective climate policies also require public support, including the willingness of the public to pay for climate-change mitigation and adaptation.