3.3 Theory of Climate Change 3.4 Observations   3.1 Introduction 3.2 The IPCC Process 3.3 Theory of Climate Change 3.4 Observations 3.5 Climate Change Prediction 3.6 US Impacts 3.7 Summary

3.6 US Impacts Global Climate Change Impacts in the United States

Global Climate Change Impacts in the United States How has climate already changed? How is it likely to change in the future? How is climate change affecting us now where we live and work? How is it likely to affect us in the future? What are our options for responding?

This report provides information we need.... to make good decisions at the national, regional, and local levels so we can avoid some of the impacts we’ll be talking about today to be able to better understand the consequences of our decisions about emissions as well as adaptation

Climate changes are underway now in the U. S Climate changes are underway now in the U.S., and are projected to grow Temperature rise Increase in heavy downpours Less snow and earlier snowmelt lead to changes in river flows Sea-level rise

Global Average Temperature, 1900 to 2100 Temperatures will continue to rise − by how much depends largely on the amount of heat-trapping gases in the atmosphere. Global Average Temperature, 1900 to 2100

Increases in very high temperatures will have wide-ranging effects. Higher Emissions Scenario, 2080-2099 Number of Days Over 100ºF Recent Past, 1961-1979 Lower Emissions Scenario, 2080-2099

Heat-related illnesses and deaths are projected to increase, especially in cities. Projected Increase in Heat-Related Deaths in Chicago

Observed Increases in Very Heavy Precipitation Heavy downpours have increased across the nation and are projected to increase further. Observed Increases in Very Heavy Precipitation (1958 to 2007)

Water resources will be affected by changing precipitation patterns and increasing temperatures. Projected Change in Precipitation by 2080-90s

Agriculture will face challenges from increased heat, pests, water stress, diseases, and weather extremes. ©Copyright

Florida with 3 feet of Sea-Level Rise Coastal areas are at increasing risk from sea-level rise and storm surge. Florida with 3 feet of Sea-Level Rise Areas in red would be under water with a 3 foot rise in sea level, projected for this century

Energy and transportation infrastructure in coastal areas faces increasing risk. Gulf Coast Area Roads at Risk from Sea-Level Rise

Climate change will affect many aspects of our lives as it alters the character of every region. ©Copyright ©Copyright

Ocean Acidification

Thresholds will be crossed, leading to large changes in ecosystems. Decreasing Habitat for Coldwater Fish Based on a Higher Emissions Scenario WA OR ID

Various effects of climate change will interact, compounding and amplifying impacts. Water and Energy Interactions ©Copyright ©Copyright

Response Strategies “Mitigation” – reducing the amount of climate change, for example, by reducing heat-trapping emissions or increasing their removal from the atmosphere “Adaptation” – improving our ability to cope with or avoid harmful impacts or taking advantage of newly favorable conditions Both will be needed.

globalchange.gov/usimpacts