The Intergovernmental Panel on Climate Change (IPCC) will release its new assessment report in Paris on February 2. Several scientists at the National Center for Atmospheric Research (NCAR) are major contributors to the report by serving as coordinating lead authors or lead authors or by reviewing drafts of the document. This year's IPCC report draws heavily on the NCAR-based Community Climate System Model (CCSM) for simulations of past, present, and future climate. NCAR's primary sponsor is the National Science Foundation. The IPCC, a group representing over 180 governments, operates under the auspices of the U.N. Environment Programme and the World Meteorological Organization. It commissions assessments of global climate change by hundreds of scientists who are experts in the field. It is now issuing the fourth in a series of periodic assessments beginning with the February 2 report by Working Group I, which focuses on the science of climate change. The assessment by Working Group I will report on observed changes in temperature, rainfall, storms, ice cover, and other climate features. It will also examine greenhouse gases, airborne particles, and other factors that affect climate, including solar variations. It will look back at past climate and include projections of future changes, both globally and regionally. Two other IPCC working groups will release their sections of the report later in the year. One will examine the impacts of, vulnerability to, and planning for climate change; the other will investigate options for mitigating climate change.