Desertification/Land Degradation in China
摘要
Due to the impacts of climate change, drylands have been increasing and are expected to continue to increase in the future. In China, a “National Survey on Desertification and Sandification (NSDS)” has been conducted every 5 years since 1994, and the sixth survey was compiled in 2019 over a period of 2 years (Fig. 2.1) (Zan et al. 2023). In the first survey from 1994 to 1996 (China National Committee for the Implementation of the UN Convention to Combat Desertification (CCICCD) 1997), 27.3% (2.26 million km2) of China’s land area was desertified. Of this, 44% was in arid areas, 35% in semi-arid areas, and 21% in dry sub-humid areas. Among the desertified lands, there were 77,000 km2 of farmland, which accounted for 40% of the farmland. Also, 56.6% of the grasslands, or 1.05 million km2, were desertified. The desertified lands included 1000 km2 of forests. According to the sixth Report of NSDS (2019), the total area of desertified lands nationwide reached 2.57 million km2, accounting for 26.8% of China’s land area, and the area of severely and extremely desertified lands accounted for more than 34% of the total desertified land area nationwide. Looking at the causes, 1.81 million km2 of land was desertified by wind erosion, 0.25 million km2 by water erosion, 0.16 million km2 by salinization, and 0.36 million km2 by freeze-thaw. More than 70% of all desertified lands in China are due to wind erosion. As can be seen from Table 1, the total area of desertified lands nationwide decreased by 38,000 km2 from 2.61 million km2 in 2014–2019. However, only 100 km2 of the desertified lands have been biologically protected, and there are still 0.28 million km2 of land that is likely to be desertified in the boundary zones of agriculture and livestock farming nationwide, and if 0.19 million km2 of grasslands, 0.05 million km2 of farmland, and 0.03 million km2 of forests are not properly protected, there is a high possibility of becoming new desertified lands.