The biennial Consultative Group on International Agricultural Research (CGIAR) Science Forum brings together scientists, practitioners, policy makers and funding agents to examine emerging challenges, identify key researchable issues and form new partnerships to address them. The theme of Science Forum 2011 is ‘The Agriculture-Environment Nexus.’ It will focus on new opportunities to adapt the agricultural research landscape to meet emerging challenges, such as: giving consideration to ecological efficiency in future agriculture; making agriculture and forestry net sinks of carbon and not sources; enabling agriculture to prosper with fewer non-renewable inputs; and developing innovative apporaches for a low-carbon agriculture that mitigates climate change. It is proposed that the debate at the Science Forum will be structured around the following themes: land saving and land transformation; resource scarcity and the ecological intensification of agriculture; metrics and monitoring; agro-biodiversity – can biodiverse systems compete in a global market?; sustainability science; and multifunctional landscapes. Science Forum 2011 will be hosted by the Chinese Academy of Agricultural Sciences (CAAS) and is organized by a steering committee led by the Independent Science and Partnership Council (ISPC) of the CGIAR.