中国区域土地利用类型转变的碳排放强度研究

The Carbon Emission Intensity of Land Use Conversion in Different Regions of China

由于土地利用变化对碳排放有着重大影响,近年来,关于土地利用的碳排放研究已逐渐成为学术界的研究热点,但目前尚没有关于全国各区域土地利用类型转变碳排放强度的详细研究。本文利用全国的植被类型图、土壤类型图以及土地利用遥感影像,借助ArcGIS9.3的空间分析功能,对中国华北地区、东北地区、华东地区、中南地区、西南地区和西北地区等六大区域的各种土地利用类型转变的碳排放强度进行了研究,并以安徽省为例,介绍了土地利用类型转变碳排放强度的应用。结果表明:①土地利用类型转变的碳排放强度在各区域间存在较大的差异,某些土地利用类型转变甚至在一些区域表现为碳排放,而在另一些区域则表现为碳汇;②林地向其它土地利用类型的转变表现出强烈的碳排放作用,而其它土地利用类型向林地的转变一般表现出最高的碳汇;③建设用地和未利用地向其它土地利用类型的转变基本表现为碳汇,而其它土地利用类型向建设用地和未利用地的转变则表现出明显的碳排放作用;④可考虑采用限制林地转出、提倡植树造林、提高建设用地节约利用、加强对未利用地的改造和防止水土流失等措施来控制土地利用碳排放。

Land use changes have a significant impact on carbon emissions;however, detailed research on the carbon emission intensity of land use conversions in different regions of China is lacking. Using vegetation and soil maps, and land use remote sensing images, we studied the carbon emission intensity of land use type conversions in six regions of China. These carbon emission intensities were then applied to Anhui Province. The vegetation map used was produced by digitizing the China Vegetation Map compiled in the 1980s;the soil type map was compiled in 1995 by the National Soil Survey Office, and 1km × 1km land use remote sensing images were provided by Institute of Remote Sensing Applications, Chinese Academy of Sciences. The six regions were Northern China, Northeast China, Eastern China, Central and South China, Southwest China and Northwest China. We found that the carbon emission intensity of land use conversion varied across regions. For example, the carbon emission intensity during the process of transferring arable land to unused land is 1.48t/hm2 in Northern China, and -0.86t/hm2 in Northeast China. Conversion of woodland to other land use types has a strong carbon emission effect, responsible for the highest carbon emission intensity in Northern China of 4.45t/hm2. The conversion of other land use types to woodland generally had the greatest carbon sink intensity. Measures such as limiting the transfer of woodland to other land use types, promoting afforestation, improving the economical use of constructed land, strengthening the transformation of unused land and preventing soil erosion would help to control carbon emissions arising from land use and change.