Regional climate change in East Asia simulated by an interactive atmosphere-soil-vegetation model

A regional coupled soil-vegetation-atmosphere model is used to study changes and interactions between climate and the ecosystem in East Asia due to increased atmospheric CO₂. The largest simulated climate changes are due to the radiative influence of CO₂, modified slightly by vegetation feedbacks. Annual precipitation increases by about 20% in coastal areas of northern China and in central China, but only by 8% in southern China. The strongest warming of up to 4°C occurs in summer in northern China. Generally, the climate tends to be warmer and wetter under doubled CO₂, except for inland areas of northern China, where it becomes warmer and drier. Most of the changes discussed in this paper are associated with changes in the East Asian monsoon, which is intensified under doubled CO₂. The largest changes and feedbacks between vegetation and climate occur in northern China. In some coastal and central areas around 40°N. temperate deciduous forests expand northward, replacing grassland due to warmer and wetter climate. Evergreen taiga retreats in the coastal northeast, causing extra cooling feedback due to less snow masking. The largest changes occur in extensive inland regions northward of 40°N, where deserts and shrub land expand due to warmer and drier conditions, and water supply is a critical factor for vegetation. These northern inland ecosystems experience considerable degradation and desertification, indicating a marked sensitivity and vulnerability to climatic change.