Abstract <p>Urban agglomerations are areas where carbon emissions are concentrated and are crucial players in achieving the carbon peak and carbon neutrality. However, research on the carbon emission correlations and carbon reduction actions of large-scale urban agglomerations is still limited. Based on the relevant data of 19 urban agglomerations in China, this study analyzes the spatiotemporal characteristics of carbon emissions from 2000 to 2019 and identifies the stage they are in during the carbon peak process with the Tapio decoupling model. Moreover, a carbon emission network is constructed, and corresponding policies from the perspective of coordinated emission reduction are sequentially put forward. The results show that: (1) The carbon emissions have obvious phased characteristics, which are basically consistent with the timeline of the five-year plan in China from 2000 to 2019. (2) The long-term total carbon emissions have not been decoupled from economic growth, and the decoupling states have evolved from expansive negative to diverse decoupling, followed by weak decoupling and no decoupling. (3) The correlation of carbon emission networks has significantly improved, and the characteristics of carbon correlation emissions within urban agglomerations are different. In addition, according to the network characteristics, urban agglomerations can be classified into two types: the center-edge type (such as the Beijing-Tianjin-Hebei Urban Agglomeration, the Harbin - Changchun Urban Agglomeration, and the Central Plains Urban Agglomeration) and the multi-growth type (such as the Yangtze River Delta Urban Agglomeration and the Chengdu-Chongqing Urban Agglomeration). These findings can provide scientific references to formulate targeted strategies for coordinated carbon emission reduction in urban agglomerations.</p> Graphical Abstract <p></p>