The UNESCAP region covers a large and diverse range of ecosystems, including deserts, forests, rivers, lakes and seas. The forest cover is second largest in the world, encompassing large tracts of biologically rich tropical forest. Over two thirds of the world's coral reefs and one third of the world's mangrove areas are also located in the region.

In recent times, three factors have contributed most directly to the excessive pressure on the environment and natural resources in the Asia-Pacific region: a doubling of the region's population over the past four decades; a tripling of the regional economic output in the last two decades; and the persistence of poverty. These pressures have been exacerbated by the recent economic downturn in the region, which has had economic and social consequences, inter alia on the capacity of some governments to implement planned activities relating to environmental protection and sustainable development.

UNESCAP's activities in the area of environment focus primarily on coordinating and monitoring the implementation of the Regional Action Programme for Environmentally Sound and Sustainable Development, 2001 - 2005, Johannesburg Plan of Implementation (JPOI), the Phnom Penh Regional Platform on Sustainable Development for Asia and the Pacific and other recommendations of the Ministerial Conference on Environment and Development in Asia and the Pacific; reviewing the regional implementation of relevant international conventions; promoting the integration of environmental considerations into economic and social planning; developing and implementing strategic environmental plans and sustainable development indicators; and promoting the increased involvement of stakeholders in achieving sustainable development goals.