This volume is the Urban Climate Change Research Network's First Assessment Report on Climate Change and Cities (ARC3). It contains an Executive Summary and the four sections of the report.

This report would not be possible without the tremendous support of the Cities Alliance, UN-HABITAT, United Nations Environment Programme (UNEP), and the World Bank. We especially thank William Cobbett and his team at Cities Alliance, Jean Christophe, Ricardo Jimenez, Sid Henderson, Neelam Tutej, Kevin Milroy, Viorica Revutch, Phyllis Kibui, and Madhavan Balachandra.

At UN-HABITAT, we are thankful to Anna Tibaijuka and Joan Clos, the outgoing and incoming Executive Directors, and their team led by Rafael Tuts with Robert Kehew and Bernhard Barth, as well as others who provided useful reviews of ARC3.

At the World Bank, we thank Inger Andersen, Vice President, Sustainable Development Department, and her team at the Urban Anchor led by Abha Joshi Ghani; Dan Hoornweg and Anthony Bigio of the Urban Anchor have been unfailingly supportive. At UNEP we would like to thank Soraya Smaoun.

We would also like to thank the Sector Managers and Directors at the World Bank and the leaders of the UNFCCC and the IPCC who have supported the need for ARC3. The Global Facility for Disaster Reduction and Recovery (GFDRR) and the U.S. Geological Survey also provided much-appreciated support for the ARC3 initiating workshop, through the enthusiastic leadership of Saroj Jha and DeWayne Cecil, respectively.