Meeting internationally discussed targets for limiting atmospheric greenhouse gas concentrations and associated increases in global average temperatures will require a major departure from business as usual in how the world uses and produces energy. This report from the America’s Climate Choices suite of studies recommends that a U.S. policy goal be stated in terms of a budget for cumulative greenhouse gas emissions over the period 2012 to 2050.
Greenhouse gas emissions and increased global temperature will change weather, climate, ecosystems, and food supply. Each degree Celsius (1.8 deg Fahrenheit) increase in global average temperature (up to 4 deg C) would likely result in the following: 5% to 10% less total rain in southwest North America, the Mediterranean, and southern Africa; 5% to 10% less streamflow in some river basins; 5% to 15% lower yields of some crops. The document clarifies short- and long-term consequences of various scenarios.
A synthesis of the current knowledge of North America's carbon budget and its context within the global carbon cycle. This report provides scientific information for decision support focused on key issues for carbon management and policy.