Land use change and carbon cycle in arid and semi-arid lands of East and Central Asia

<正> Dramatic changes in land use have occurred in arid and semi-arid lands of Asia duringthe 20th century. Grassland conversion into croplands and ecosystem degradation is widespreaddue to the high growth rate of human population and political reforms of pastoral systems. Rangeland degradation made many parts of this region vulnerable to environmental and political changes. The collapse of the livestock sector in some states of central Asia, expansion of livestockin China and intensive degradation of grasslands in China are examples of the responses of pastoral systems to these changes over the past decades. Carbon dynamics in this region is highly variable in space and time. Land use/cover changes with widespread reduction of forest and grasslands increased carbon emission from the region.