Global effects of progress towards SDGs on steeply sloped land use and land cover.

Flat, highly suitable land for construction and cultivation is limited, and socio-economic development and population growth will surely lead to the exploitation of steeply sloped land, which is very difficult to use and extremely ecologically sensitive. Understanding how the trade-offs and synergies between economic development, social progress and ecological protection within the framework of the Sustainable Development Goals (SDGs) affect the exploitation and protection of steeply sloped land in an integrated manner should be an important part of land resources management, but is rarely addressed in existing research. Therefore, we produced global map of steeply sloped land use and land cover in 2020 with the spatial resolution of 10 m × 10 m, and its distribution and structural characteristics were analyzed, the levels of achievement of the 17 sub-SDGs and these effects on steeply sloped land use and land cover structure were quantified. Results showed that: The distribution of steeply sloped land use and land cover around the world is extremely uneven. Area of steeply sloped land use and land cover in 54 countries exceeds 50%, and these countries or regions are mainly located in Asia and Europe. Global steeply sloped land use and land cover includes all types of commonly used land use and land cover classifications, which is mainly composed by tree cover, grassland, and bare/sparse vegetation, accounting for 48.663%, 21.418%, and 14.876% respectively, and cropland is the main land use type. the level of achieving the SDGs of essential needs and objectives shows the most significant negative direct effects on the amount of ecological space in the global steeply sloped land use and land cover system (-0.526, -0.318), the level of achieving the SDGs of governance has clear positive direct effects on the amount of construction space and ecological space (0.403, 0.324). The 17 sub-SDGs and the global steeply sloped land use and land cover structure also exert indirect effects through their interactions. Our conclusion is that it is necessary to strengthen the systematic monitoring of global steeply sloped land use and land cover, as well as the need for effective control of global steeply sloped land exploitation.