Carbon emission and ecological compensation of main functional areas in Sichuan Province based on LUCC

Carbon emissions under land use/cover change (LUCC) reflect the disturbance degree of environment by human activities. Therefore, carbon budget and compensation research was of great significance to regional low-carbon economy and balanced development. Based on land use data for Sichuan Province in 2005 and 2015, this paper built a new local land use classification system and carbon emission model to quantitatively analyze carbon emission and carbon offset rate of land use in 183 counties in Sichuan Province. Taking into account regional differences at county level and breaking traditional administrative regional boundaries, the study based on the five main functional areas of Sichuan Province to measure ecological compensation standards with afforestation cost and carbon tax rate methods. The results showed that:1) during the study period, land use in each main functional area in Sichuan Province was consistent with the main functional area planning and was optimized according to the functional orientation. Cultivated lands in the key development area had absolute advantage, while the total amount and increase in construction land area was the largest. Otherwise, cultivated land holding capacity in the main agricultural production area remained the strongest. Woodland and grassland accounted for 70%-80% in the key ecological function areas. 2) During the study period, total carbon emission in each main functional area increased significantly, and the construction land was the main carbon source, and forest land was the main carbon sink. Total carbon emissions and increments in the key development area ranked first, with carbon sinks in the key ecological functional area accounting for 63% of Sichuan Province, although the ability to absorb carbon gradually weakened. 3) Carbon emission intensity of construction land of each main functional area was much greater than total carbon emission intensity. Total carbon emission intensity of each main functional area increased during the investigated period, but carbon emission intensity of construction land showed increased or decreased. Total carbon emission intensity of the key development area at national level was largest, while that of construction land was smallest. 4) The rate of carbon compensation in the ecological development areas was high, with economic development area having the reverse trend. The compensation coefficient of carbon absorption was highest for the restricted development area at national level (key ecological function area). 5) Carbon source area provided ecological compensation for carbon sink area based on the scope of ecological compensation. Ecological compensation standard for Ganzi Tibetan Autonomous Prefecture, which was a carbon sink area, was 5.82 billion to 20.56 billion Yuan. It indicated that carbon emission was correlated with functional location of each functional area. Ecological compensation standard generally decreased from Chengdu Plain to the surrounding areas, and ecological compensation standard of the restricted development areas were relatively low. On the basis of the ecological compensation standard for carbon emissions, a horizontal fiscal transfer payment policy was established as reference basis for energy conservation, emission reduction and balanced development of Sichuan Province.