Climate change is a major challenge to international cooperation, as emphasized for instance by the Stern Review and various IPCC reports (Stern 2006; IPCC 2007) but also many others. One of the main problems of achieving cooperation under international climate agreements is free-riding. Countries have an incentive to adopt a non-cooperative behaviour. Emission reduction constitutes a public good. No country can be excluded to benefit from the emission reduction of other countries. Moreover, by not contributing to emission reduction, a country saves on abatement cost. The Kyoto Protocol ran out in 2012, but all efforts to negotiate an effective follow-up protocol have failed up to now. The reason is not that no negotiations would have taken place, but simply that no proposal was yet formally adopted which sets emission ceilings such that greenhouse gas emissions are stopped from further growing. What is required are substantial cut backs on emissions in order to meet the widely accept target of not allowing the average global temperature to increase beyond 2 ∘C. The seven papers in this special issue look at various important aspects related to the international dimension of climate policy. The first five papers are theoretical papers, the last two papers employ a climate simulation model combined with a game theoretic module to derive their results. Issues that are covered are for, instance, the problem of long-term commitment of governments to a proactive climate policy, the role of R&D in clean technologies, in terms of how they are induced through various policy instruments but also how spillovers and adoption of green technology can support international cooperation, the role of ancillary benefits for the success of climate agreements, the relationship between trade and climate policy, the design of supply-side climate policies to address the green paradox, the driving forces that support or undermine a unilateral climate policy without full participation and finally the role of fat tail distributions of uncertain damages on the performance of partially cooperative climate agreements. In the following, we summarize these papers briefly and encourage the reader to have a careful read of this excellent selection of papers, which span a wide range of important topics in the current debate about an effective way forward in addressing the climate change problem.