Abstract: Carbon emissions trading is a policy tool that uses market mechanisms to reduce greenhouse gas (GHG) emissions. Carbon trading plays an increasingly important role in driving corporate decarbonization, fostering green technology innovation, and improving resource allocation efficiency. Since the launch of China’s national carbon market in 2021, by December 31, 2024, the total volume of allowances traded had reached 630 million tons, with a transaction value exceeding 43 billion RMB. The carbon market has become a key policy tool for China to implement its “dual carbon” strategy. This study systematically reviewed the development and operation of global and China’s carbon markets in 2024, analyzing the direct GHG emission reduction effects and co-benefits of air pollutants emission reductions based on official monitoring data and research literature. The results show that carbon markets based on a cap-and-trade system effectively reduce total GHG emissions within a region, while intensity-based carbon markets on targets lower carbon intensity without restricting corporate development. In addition to reducing GHG emissions, the implementation of carbon trading also generates synergistic benefits by reducing air pollutant emissions. It is expected that the global carbon market’s cap-and-trade mechanism will continue to improve, intensity-based mechanism will develop rapidly, global cooperation will deepen, and regulatory transparency will be continuously strengthened. It is recommended that China’s national carbon market clarify its development path and enhance market effectiveness by strengthening policy expectations, refining the allowance mechanism, and reinforcing emission reduction constraints.