State and change of Dryland East Asia (DEA)
Dry land East Asia (DEA) refers to a region with 4.81 million square kilometers (km²) and includes Mongolia and four provinces/regions in Northern China (hereafter called "administrative units" ): Inner Mongolia, Gansu, Ningxia, and Xinjiang. This introduction chapter provides an overview of the DEA region from three perspectives: 1) geography, demography, and economics, 2) climate and land use changes, and 3) ecosystem production and evapotranspiration. Development of a sound adaptation plan, therefore, is becoming a necessity for the sustainable future of a region such as DEA. We emphasize t he spatial and temporal variations of the major variables associated with each of the three topic areas. Finally, we discuss the scientific and societal challenges for developing adaptation plans based on the concept of coupled natural and human (CNH) systems.