The U.S. Biennial Report, as part of the 2014 U.S. Climate Action Report, outlines how U.S. action on climate change puts the United States on a path to reach the ambitious but achievable goal of reducing U.S. greenhouse gas (GHG) emissions in the range of 17 percent below 2005 levels by 2020.During 2009-2011, average U.S. GHG emissions fell to the lowest level for any three-year period since 1994-1996, due to contributions from both economic factors and government policies. The United States has made significant efforts over the past five years, and our progress can be attributed in part to these efforts, including stringent, long-term standards for vehicle GHG emissions and efficiency, increased building and appliance efficiency, and doubling electricity generation from wind and solar.The President's Climate Action Plan (EOP 2013a), released in June 2013, builds upon the progress of the past five years and outlines significant additional actions that are necessary to maintain the downward trend in U.S. GHG emissions, such as putting in place new rules to cut carbon pollution from the power sector, increasing energy efficiency, and reducing methane (CH4) and hydrofluorocarbon (HFC) emissions. The plan also initiates efforts to bolster the capacity of our forests and other lands to continue sequestering carbon in the face of a changing climate and other pressures. We expect that implementation of these actions will achieve substantial additional emission reductions.This report is a first step toward tracking our progress toward meeting the U.S. 2020 emission reduction goal. It represents an assessment of the range of GHG emission reductions that implementation of a collection of actions across sectors of the economy, consistent with those included in The President's Climate Action Plan, can achieve. Over the coming years, as standards and policies are put in place, we will sharpen our estimates of achievable emission reductions.In addition, this report discusses U.S. actions to assist developing countries in their efforts to mitigate and adapt to climate change. The United States is engaging the full range of institutions- bilateral, multilateral, development finance, and export credit-to mobilize private finance and invest strategically in building lasting resilience to unavoidable climate impacts; to reduce emissions from deforestation and land degradation; and to support low-carbon development strategies and the transition to a sustainable, clean energy economy.