www.energy.gov/topics/climate

This report: 

• Reviews scientific certainties and uncertainties in how anthropogenic emissions of CO₂ and other GHGs have affected, or will affect, the Nation’s climate, extreme weather events, and metrics of societal well-being.
• Assesses the near-term impacts of elevated concentrations of CO₂, including enhanced plant growth and reduced ocean alkalinity.
• Evaluates data and projections regarding long-term impacts of elevated concentrations of CO₂, including estimates of future warming.
• Finds that claims of increased frequency or intensity of hurricanes, tornadoes, floods, and droughts are not supported by U.S. historical data.
• Asserts that CO₂-induced warming appears to be less damaging economically than commonly believed, and that aggressive mitigation policies could prove more detrimental than beneficial.
• Finds that U.S. policy actions are expected to have undetectably small direct impacts on the global climate and any effects will emerge only with long delays.