There is a growing consensus among scientists as well as policymakers that climate change is a serious problem that must be addressed. The recently released summary of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) once more confirmed in still stronger language that climate change is already happening and that humans have ‘very likely' caused most of the warming over the last fifty years. Projected warming by 2100 for business-as-usual scenario may be as large as 6°C or more globally, depending on the scenario chosen and particular climate model used, with larger warming over continental regions and in the high latitudes, an Arctic ocean free of late summer ice, a rise in sea level, widespread changes in precipitation and extreme weather events. We are carrying out at NCAR, DOE's Oak Ridge National Laboratory, and the National Energy Research Scientific Computing Center several low emission scenarios that are based on the recent Climate Change Science Program (CCSP).The details of how these scenarios are developed is discussed in the CCSP Synthesis and Assessment Product 2.1a report. The impact of increased use of conservation, renewable, and other energy strategies is substantially less global warming than found in the IPCC scenarios used in the last assessment. Both regional and global results will be discussed.