This Policy Brief focuses on government policies that are contributing to the mitigation of emissions of greenhouse gases and particulate matter. The emphasis is on policy solutions and paths into the future. The analysis highlights developments that have already made significant contributions to on-going efforts to reduce the impacts of climate change through mitigation actions. However, this hopeful approach to dealing with climate change is based on a realistic appraisal of the catastrophic paths the world is now following. The problems are already severe, and they are expected to become much more so in coming years. Yet, it is also true that there are many ways to reduce their severity. This Policy Brief is a multi-disciplinary guide to the facts about what policies have been adopted or are being developed and the benefits of their adoption. Among the countries included are Brazil, Canada, China, the EU-27, India, the Nordic-5, UK, US and others.