Clarifying the spatial distribution characteristics of carbon emission and ecological risk of land use at a grid—scale can provide a new perspective for the sustainable development of local ecosystems. Focusing on the Changsha-Zhuzhou-Xiangtan (CZT) urban agglomeration, this study examined the spatial and temporal dynamics of carbon and ecological risks using land use, night light, and socioeconomic data from 2012 to 2022. Furthermore, this study investigated how these risks were spatially clustered using a bivariate spatial autocorrelation model. The results showed that: (1) From 2012 to 2022, the total area of land use conversion reached 81.322×104hm2. Construction land expanded the most, while water area shrank the most. (2) Net carbon emissions decreased by 1101.869×104t. The risk of carbon emission (CR) has been diminishing, and the spatial distribution exhibits a multi-"core-edge" circle structure. (3) Ecological risk (ER) showed a slight overall downward trend, with the spatial distribution pattern characterized by a gradient of decreasing intensity radiating outward from the center, which is focused around Dongting Lake and the Xiang River basin. (4) Moran's I changed from 0.256 to 0.309 during the study duration. There was a significant positive correlation between carbon and ecological risks, and the positive effect was further strengthened. Spatially, high—low and high—high cluster showed a weakening trend. The low—low and low—high cluster showed an increasing trend. The spatial homogeneity between areas of high (low) carbon risk and areas of high (low) ecological risk was further evidence of the positive driving effect of carbon risk on ecological risk.