The coupling and coordinated relationship between the ecological environment and carbon emissions is critical to the sustained development of human society. The remote sensing eco-index (RSEI) model has been applied to the assessment and monitoring of ecological environment quality, but RSEI neglects air pollution, and thus this study introduced aerosol optical depth (AOD) into the index system and constructed a novel ARSEI to evaluate the ecological environment quality and analyze the spatial-temporal changes in ARSEI and energy-related carbon emission (ECE) at the county level in China. Additionally, we further investigate the local relationship between ARSEI and ECE in China by using the coupled coordination model (CCD). The outcomes showed that: (1) Compared with the RSEI, the ARSEI widened the gap in ecological quality between the east and the west along the Heihe-Tengchong line; (2) ARSEI value was significantly increased in 24.70% of areas in China, mainly in the Northeast Plain, Loess Plateau, and Tarim Basin. ARSEI value was significantly decreased in 5.35% of areas in China, mainly in the Qinghai-Tibetan Plateau, the northern part of the Tianshan Mountains, eastern coastal cities, and central urban agglomerations; (3) ECE dispersed from east to the west from 2000 to 2017, with an average annual increase of > 0.3 megatons in 354 counties, densely distributed in the eastern coastal urban agglomerations, Loess Plateau, and sporadically distributed in some central and western cities in China; (4) CCD distribution showed a “west-low-east-high” pattern, with an upward trend in CCD value in the majority of surveyed counties (2,241), and a downward trend in some counties (171) in southwest, south, and central China. Based on these results, recommendations are proposed at the county and above levels for coordinated and sustainable development of urban economy and ecology.

Northeast China is experiencing severe soil erosion, resulting in land degradation and nutrient loss. Among them, hydraulic erosion poses the greatest threat to food security. Combining various multi-source data, we applied the modified soil erosion equation (RUSLE) to evaluate hydraulic erosion modulus in Northeast China’s black soil region(1985–2021). We used the threshold segmentation and residual analysis method to quantify the relative roles of climate change and human activities on hydraulic erosion. The outcomes were presented below: (1) The yearly mean hydraulic erosion modulus was 804.78 t·km -2·a -1 and decreases significantly with a slope of -11.114 t·km -2·a -1. The area with significant growth in erosion modulus covered 23.77% of the overall area and was mainly spread in grassland and farmland. The areas with a significant decrease in erosion modulus covered 19.82% and were mainly spread in natural forests. (2) In areas with significant increases in erosion, 20.39% of the total area was attributed to anthropogenic factors and 3.38% of the total area was attributed to natural factors. In areas where soil erosion was significantly reduced, 17.67% and 2.15% were attributed to ecological restoration and natural factors, respectively. (3) Deforestation, grassland degradation, and unreasonable farming still exist. The area of sloping cropland (≥6°) increased by 133.9 km 2 per year, and sloping land erosion increased by 0.187 · 10 10 t per year. The focus of soil erosion prevention and control in northeast China is ecological restoration of grasslands, sloping land management, and conservation tillage.