1. Global climate change : a new type of environmental problem -- 1.1. Background on climate and climate change -- 1.2. Background on climate-change policy -- 1.3. Plan of the book -- 2. Science, politics, and science in politics -- 2.1. Justifications for action : positive statements and normative statements -- 2.2. How science works -- 2.3. Politics and policy debates -- 2.4. When science and politics meet -- 2.5. Limiting the damage : the role of scientific assessments -- Further reading for chapter 2 -- 3. Climate change : present scientific knowledge and uncertainties -- 3.1. Is the climate changing? -- 3.2. Are human activities responsible for global warming? -- 3.3. What future changes can we expect? : predicting climate change over the twentyfirst century -- 3.4. What will the impacts of climate change be? -- 3.5. Conclusions -- Further reading for chapter 3 -- 4. The climate-change policy debate : impacts and potential responses -- 4.1. Impacts and adaptation -- 4.2. Emissions and mitigation responses -- 4.3. Putting it together : balancing benefits and costs of mitigation and adaptation -- 4.4. A third class of response : geoengineering -- 4.5. Conclusion : policy choices under uncertainty -- Further reading for chapter 4 -- 5. The present impasse and steps forward -- 5.1. Climate-change politics : present positions -- 5.2. Climate-change politics : the arguments against action -- 5.3. The present policy debate : use of scientific knowledge and uncertainty -- 5.4. So what should be done? : major choices and elements of an effective response -- 5.5. Conclusion -- Further reading for chapter 5 -- Appendix -- Glossary.