土地利用/覆盖变化是学术界最为关注的环境变化问题之一，它能够影响陆地生态系统的生物多样性、水、碳和养分循环、能量平衡，引起温室气体释放增加等其它环境问题。不同类型的土地利用/覆盖变化对生态系统碳循环的作用不同，由高生物量的森林转化为低生物量的草地、农田或城市后，大量的CO2将释放到大气中。全球土地利用/覆盖变化具有很强的空间变异性，对生态系统碳循环的影响同样具有明显的空间差异：热带地区的土地利用 /覆盖变化造成大量的碳释放，而中高纬度地区土地利用/覆盖变化则表现为碳汇。目前，土地利用/覆盖变化引起的生态系统碳循环变化主要是通过模型模拟来估算的。尽管土地利用/ 覆盖变化及其相关过程与生态系统碳循环的关系已经比较清楚，但是，由于土地利用/覆盖变化过程复杂且影响广泛，对于如何量化两者之间的关系还存在很多不确定性。目前的量化过程主要是利用经验数据来实现的，机理性不强，使得对土地利用/覆盖变化造成的陆地生态系统CO2释放量的估测差异很大。除了进一步加强长期定位研究以获得土地利用/覆盖变化与生态系统碳循环过程的定量关系外，土地利用/覆盖变化模型与植被动态模型、生态系统过程模型的耦合也是今后模型发展的主要方向之一。采用合理的管理措施能够大量增加土地利用/覆盖变化过程中的碳储存量，降低碳释放量，因此在模型中耦合管理措施来研究土地利用/覆盖变化过程对生态系统碳循环的影响是未来几年的工作重点。
Land use/cover change (LUCC) is one of the most concerned environmental problems by scientists, land managers and policy makers. LUCC can affect
energy flow, biogeochemical and hydrological cycling in terrestrial ecosystems through altering land surface and species composition. Ecosystem carbon cycling responds differently to various LUCC types, showing a pattern of CO2 release into the atmosphere when LUCC from a high-biomass forest to low-biomass grassland, cropland or urban area. Previous reports indicated that global terrestrial ecosystem released 2.21 Pg C (1 Pg C=1015g C) per year induced by LUCC during the 1990s, which explain s about 25% of the global C emission per year in the same period; and in the last two centuries, the released C from LUCC accounts for 50% of the C emission from fossil fuel combustion. The LUCC patterns are totally diversified for regions around the world, which cause obviously different C fluxes among them. The reports showed that LUCC in the tropics is a C source, while it is a C sink in the middle and high latitude regions in the northern hemisphere, which possibly explain a large part of the “missing carbon sink" in the terrestrial ecosystems. Currently, modeling is the most popular way to simulate LUCC-induced changes in ecosystem C cycling. The quantitative relationship between LUCC patterns and their related processes and ecosystem carbon cycling remains uncertain. This uncertainty causes great discrepancies in the estimation of terrestrial ecosystem CO2 fluxes from land use/cover changes. In the near future, except for carrying on long-term experiments to determine these quantitative relationships, model development by integrating LUCC with vegetation dynamic model and ecosystem process model will be essential for making an accurate estimation of C fluxes induced by LUCC. Sound land management can greatly increase C storage in the terrestrial ecosystems during LUCC processes. However, the quantification of land management effects is not well-established yet and land management is thus not included in most simulation models of LUCC impacts, which needs more researches in the future.