To optimize land use structure in Zhejiang province, this paper uses carbon footprint model to estimate the carbon footprint level from 2007 to 2016 and applies decoupling and standard ellipse variance to study the carbon emission effect of land use in Zhejiang province. The results show a growth rate of 4.06% in net carbon emission in Zhejiang province from 2007 to 2016, most from construction land use. Gap between carbon source and carbon sink is enlarging, making low carbon development difficult. Ningbo city ranks the top in net carbon emission, and Lishui city, which is the only city of carbon sink more than carbon source, is at the bottom. The gap of carbon emission in northeast and southwest Zhejiang province is increasing. The GDP per capita in Zhejiang province is of weak decoupling with carbon footprint per capita, with economic development faster than carbon emission rising rate. Lishui is the best and Zhoushan is poor in decoupling. The spatial distribution of net carbon emission and construction land carbon emission is concentrated in northeast Zhejiang province. The farmland carbon emission is sparsely distributed with the center in the southwest.

 The coastal area in Jiangsu province is the major crop producer, where ensure the guarantee of Jiangsu's crop supply. This paper, based on farmland-crop-population compound system, uses farmland pressure index model to estimate the population carrying capacity model, and to evaluate the actual population carrying capacity. The population carrying capacity in three coastal cities in Jiangsu in 2025 is predicted under the condition that the 2nd Child policy is open to all, which is used to plan a rational urban population size. During 1998—2014, farmland decreased in area, but population rose continuously, leading a largely falling in farmland area per capita; however, the total crop production was a little rising. The overall population carrying capacity pressure is small in Jiangsu's coastal area, Nantong sits on top, followed by Lianyungang and then by Yancheng. It is predicted that in 2025 the appropriate population is 6.4 million in Nantong, 9.78 million in Lianyungang and 17.56 million in Yancheng, maximum up to 8.00 million, 12.23 million and 21.95 million, respectively.