With a population comparable to that of the United States but with only one quarter of the area and a small fraction of the wealth, the Greater Mekong Subregion (GMS) encompasses six culturally, ethnically and linguistically diverse areas.

About 250 million people, most of them in rural areas, occupy the five countries and one province of the GMS: Cambodia, Lao People's Democratic Republic, Myanmar, Thailand, Viet Nam, and Yunnan Province in the People's Republic of China. Their common link is the mighty Mekong River, winding its way for 4.200 kilometers through their midst, endowing the subregion with a rich natural resource base.

The main rivers traversing the subregion are - from west to east - the Ayarwady, Thanlwin,Chao Phraya, Mekong, and Red. The numerous tributaries to these rivers are escorted by wetlands, lakes, and drainage basins. Major deltaic formations exist in estuaries of the Ayeyarwady, Chao Phraya, Mekong and Red rivers. Large dams in the course of the main rivers created artificial environments for fish production.

Ten million years of changing sea levels have left an extremely rich legacy of unique life forms that have evolved in the isolation on the Cardamom and Andamite mountains of Cambodia, Lao PDR, Thailand and Vietnam. The Biodiversity and high abundance of endemic species is only outmatched by the amazonic basin in South America. In addition to the richness of the flora and fauna the subregion is blessed with large resources of timber, minerals, coal and petroleum, while myriads of creeks and rivers as tributaries to the main rivers, provide abundant water resources for agriculture, fisheries and hydropower. Despite the abundance of fossil energy resources and hydropower 55 million people - more than one fifth of the combined population of the subregion - lived in poverty in 2000.

As much as the six GMS countries are connected through the Mekong River are the economies intervened with each other. All countries were severly hit by the Asian Financial Crisis in 1997 when the stock markets crashed after a period of strong growth in the 1990s. Allthough the crisis started 1997 in Thailand the country remains the regions powerhouse with a per capita gross national product of $2.000.

Life expectancy in the subregion in general exceeds 60 years, while Cambodia and Lao PDR suffer from high infant mortality rates (95 and 90, respectively, compared with Singapor´s 3 per 10.000 live births) while the maternal mortality ratio per 100.000 live births is also high in Lao PDR (at more than 500), Cambodia (more than 400), and Myanmar (more than 200) compared with Singapore´s 2 per 100.000.

Good arable land is scarce in the subregion mainly because of high population densities along the Mekong River and hilly or mountainous terrain so that there is a high pressure on natural resources through land reclamation. Especially wetlands and primary and secondary forest ecosystem are being converted in intense food production areas. The alteration of water quality because of the changed land use, the vulnarability of the newly won agricultural land in terms of altered flood paterns, the heavy loss of endemic and endagered plant and animal species, because of the rapid reduction of wetlands are contradicting a sustainable land use.

The sell out of different natural resources for export to other countries have had a serious impact on biodiversity, especially in the poorer countries of the subregion which have a weak infrastructure. Main sources of nutrition and relative wealth in the subregion are heaviely related to the abundant fresh and saltwater reserves. Containing a total of 1.600-1.800 fish species the Mekong basin is one of the most productive and diverse freshwater fisheries world wide, only second to the Amazone. With a total annual freshwater catch including aquaculture production of 3.1 million tons compared to an overall catch from salt and seawater fish of 6.8 million tons per year the significance of the GMS becomes understandable. With innumerable inland riverine areas and wetlands aquaculture has become part of the food production early in the GMSs countries culture and is contributing half of the total freshwater catch in Vietnam and Thailand today. With the conversion of wetlands to aquaculture or arable land local people loose an important source of diverse food sources and thereby become threatend by malnutrition.

The economical growth and the rising living standards are producing further pressure on the environment and its natural resources. The development of infrastructure could adversely affect biodiversity as land is cleared to make land for transmission lines and the expansion of regional areas. Especially hydropower planning requires a well coordinated planning in subregional cooperation to achieve its sustainability and minimize its impact on environmental issues and natural resources. If the region is to become a growth center further water regulation plans, including channelising the Mekong River upstream and improved irrigation system will have to be carefully planned and set in place to ensure a sustainable use for coming generations. Future tasks will also include reduction and stronger regulation concerning illegal cross border trade in timber, wildlife, and expansion of protected areas, parks and nature reserves across borders to conserve rare and endangered species. Although logging is regulated by the governments in all GMS countries its enforcment is insufficient and the closure of production forests in Yunnan PRC, Thailand and Vietnam have put even higher pressure on the remaining natural forests in Cambodia, Lao PDR, and Myanmar.