.. . Popular summary- Impact of Urban Surfaces on Precipitation Processes J. Marshall Shepherd-Contributing Author Intergovernmental Panel on Climate Change (IPCC) Assessment Report 4-Section 3.3 of Chapter 3 The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two Ufitai-NaGon~ organizations, the World Meteorological Organization (WMO) and the United Nations Environment Pro~amme(U NEP) to assess the "risko f human- induced climate change". Such reports are used by decision-makers around the world to assess how our climate is changing. Its reports are widely respected and cited and have been highly influential in forming national and international responses to climate change. The 4* Assessment report includes a section on the effects of surface processes on climate. This sub-chapter provides an overview of recent developments related to the impact of cities on rainfall. It highlights the possible mechanisms that buildings, urban heat islands, urban aerosols or pollution, and other human factors in cities that can affect rainfall.