Climate change is one of the greatest challenges facing humankind today. Its global scope and multigenerational scale make it uniquely daunting. The United States is one of the world’s largest consumer of hydrocarbons and one of the largest emitters of greenhouse gases (GHGs) and, thus, must play a key role in any global effort to reduce GHGs. American scientists have been at the forefront of the emerging scientific consensus on the human role in climate change, and U.S. policymakers, politicians, academics, and the media have been struggling in recent years to fashion a concrete response.
While advances in climate science continue to improve our understanding of how climate change is likely to impact our world, addressing climate change is a complex public policy issue because the challenges are global and will span several generations. It will require global cooperation on a scale never before achieved in human history. The complexity of dealing with the challenges presented by climate change, through both mitigation and adaptation, means that the policy responses must be equally diverse and multidimensional, including the full spectrum from international agreements and programs to local efforts.