CHAPTER ONE Climate Change: Cause and Evidence: Evidence for Global Warming; The Earth's Energy Balance; Greenhouse Gases; Climate Forcing Factors and Feedbacks; Global Chmate Models; Future Climate Projections: Evidence to Date; The Rest of the Story. CHAPTER TWO Past Climates: Proxy Thermometry and Age; Sun-Earth Geometry and Climate; Ancient Climates; The Younger Dryas Event; The Little Ice Age; Changing Communities. CHAPTER THREE Plant Physiognomy and Physiology: Plant Demand for Water and Energy; Plant Physiognomy; Plant Physiology; Causes of Forest Decline; Fire; Phenology; Once and Future Vegetation Patterns. CHAPTER FOUR Past Vegetational Changes: Vegetation Migration in North America; Vegetation Responses to the Younger Dryas Event; Plant-Climate Response; Boreal Forest Movement; Rates for Individual Species; Lessons for the Future. CHAPTER FIVE Forest Models and the Future: Forest Modeling Simulated Forest Futures; Other Forest Gap Modeling; Forest Sensitivity to Temperature Change; Empirical Modeling; Forests and Other Organisms. CHAPTER SIX Ecosystems: Ecosystems; Ecosystem Responses to Climate; Loss of Species Diversity; Birds; Mammals; Reptiles; Amphibians; Fish; Insects; The Great Lakes Ecosystems; Lakes of the Central Boreal Forest; Sea Level Rise and Wetland Loss; Ozone Depletion, Ultraviolet Radiation, and Life; The Antarctic Ecosystems. CHAPTER SEVEN Agriculture, Droughts, and El Nino: Crop Modeling; Climate Change Scenarios; Crop Model Results; Wheat Production in North America; Irrigation Water Requirements in the Great Plains; Caiifomia Agriculture Yields and Climate Change; The MINK Region; Climate Impacts on Pest-Plant Interactions; Livestock and Climate Change; Drought. CHAPTER EIGHT What to Do: Strategies; Technological Fixes; Into the Future.