Addressing global change challenges for Central Asian socio-ecosystems

Central Asia is one of the most vulnerable regions on the planet earth to global climate change, depending on very fragile natural resources. The Soviet legacy has left the five countries （Kazakhstan, Tajikistan, Kyrgyzstan, Turkmenistan, and Uzbekistan） with a highly integrated system but they are facing great challenges with tensions that hinder regional coordination of food and water resources. With increasing climate variability and warming trend in the region, food and water security issues become even more crucial now and, if not addressed properly, could affect the regional stability. The long-term drivers of these two most critical elements, food and water, are climate change; the immediate and probably more drastic factors affecting the food and water security are land uses driven by institutional change and economic incentives. As a feedback, changes in land use and land cover have directly implications on water uses, food production, and lifestyles of the rural community in the region. Regional and international efforts have been made to holistically understand the cause, extent, rate and societal implications of land use changes in the region. Much of these have been understood, or under investiga- tion by various projects, but solutions or research effort to develop solutions, to these urgent regional issues are lacking. This article, serves as an introduction to the special issue, provides a brief overview of the challenges facing the Central Asian countries and various interna- tional efforts in place that resulted in the publications of this special issue.

Remote sensing of land use/cover changes in South and Southeast Asian Countries

Land-Use/Cover Changes(LU/CC)are occurring rapidly in South/Southeast Asian(S/SEA)countries,generally associated with population growth,economic development and competing demands for land.In the region,the most common LU/CC changes include urban expansion,agricultural land loss,land abandonment,deforestation,logging,reforestation,agricultural expansion,etc.Specific to South Asia,forest cover has been increasing in countries like India,Nepal,and Bhutan due to sustainable afforestation measures;whereas,large-scale deforestation in Southeast Asian countries is continuing,for example,due to oil palm plantation expansion driven by the international market demand in Malaysia and Indonesia.Small-scale deforestation in most of the Southeast Asian countries is due to slash-and-burn agriculture by indigenous people,driven by poverty and population growth.Logging activities are common in Myanmar and Cambodia.In terms of urbanization,South and Southeast Asian countries contain 23 megacities,each with more than 10 million people.Megacities in these countries started as urban clusters which grow rapidly,merging into conurbations.Rapid urbanization is driving agricultural land loss,and agricultural intensification has been increasing due to less availability of land for growing food crops as,for example,in India,Vietnam,and Thailand.The drivers of LU/CC vary widely in the region and include such factors as land tenure,local economic development,government policies,inappropriate land management,land speculation,improved road networks,etc.Also,variability in the weather,climate,and socioeconomic factors drive LU/CC resulting in disruptions of biogeochemical cycles,radiation and surface energy balance.