全球土地覆被时空变化与中国贡献

20世纪下半叶以来全球土地覆被发生了剧烈变化,人类活动对土地覆被变化的影响成为“人类世”最为显著的特征之一。科学评估全球土地覆被变化的时空过程和新态势,分析中国在其中扮演的角色和地位并提出优化路径,成为中国在可持续发展领域应对全球百年未有之大变局的核心任务之一。本文基于多源土地覆盖数据,运用地理空间分析方法定量刻画了全球土地覆被变化的时空演化过程,从景观尺度分析了地类间的转化关系以及全球“变绿”和森林覆盖度的变化趋势,揭示了中国对全球土地覆被时空变化的贡献。结果表明,1992—2015年全球土地覆被经历了显著变化,全球土地覆被变化度在南美洲中部、撒哈拉以南的非洲、中亚、东南亚和东亚等地形成显著的热点区。中国森林覆盖率从1990年的12.98%增至2020年的23.34%,湿地面积增长1908 km²,为维护全球生态安全贡献了力量,同时在城市用地增长、草地和其他用地减少等方面也有一定的限制作用。与全球其他国家不同,中国城市扩张占用耕地面积居全球第一位,高达7.3万km²。1999—2019年全球叶面积指数存在全球性的显著提高趋势。中国以仅占全球6.6%的植被面积,贡献了全球20%左右的叶面积增加量,引领了全球“变绿”过程。1990—2020年全球森林覆盖度变化呈现出空间集聚性。中国森林面积增长62.84万km²居全球前列,其中西南林区和秦巴山区是林地增长的主要区域,长三角、粤港澳大湾区和内蒙古东部部分地区是森林覆盖度降低的主要区域。中国未来应进一步提升经济社会发展与生态保护的均衡协调度,持续推进美丽中国建设,为全球生态安全和可持续发展贡献更大力量和更多经验。

Spatio-temporal change of global land cover and China’s contribution

In recent decades,the global land cover has undergone drastic changes,and the impact of human activities on land cover change has become one of the most significant features of the "Anthropocene".The core tasks of coping with global "unprecedented changes in a hundred years" for China in the field of sustainable development is to scientifically assess the spatio-temporal process and new trends of global land cover change,analyze China’s role and status in it,and propose optimal paths.We used geospatial analysis method and multisource land cover data to explore the spatio-temporal process of global land cover change,analyze the transformation relationship between land types and the change trend of global "greening" and forest cover,and reveal the new characteristics and trends of land cover change in China.The results showed that the global land cover experienced significant changes from1992 to 2015,and several hot spots formed,including central South America,sub-Saharan Africa,Central Asia,Southeast Asia and East Asia.China’s forest coverage rate increased from12.98% in 1990 to 23.34% in 2020,and the wetland area increased by 1908 km2,which contributed to the maintenance of global ecological security.The interactive conversion between cultivated land and forest is the most important land cover conversion relationship in the world.In terms of cultivated land occupied by urban land,China ranks first in the world,with an area of 73000 km2.The global leaf area index presented a global trend of significant increase from 1999 to 2019.With only 6.6% of the world’s vegetation area,China contributed about 20% of the global increase in leaf area index and dominated the global "greening" process.The change of global forest coverage presents remarkably spatial agglomeration.China’s forest area increased by 62.8376 million hectares(1990-2020),leading the world in forest restoration.The southwest China forest region and the Qinling-Daba mountains are the main areas of forest growth,and the Yangtze River Delta,the Guangdong-Hong Kong-Macao Greater Bay Area and parts of eastern Inner Mongolia are the main areas of deforestation.In the future,China should further enhance the balance and coordination between socioeconomic development and ecological protection,continue to promote the building of a beautiful China,and contribute more strengths and experiences to global ecological security and sustainable development.