Feasible carbon-trade model for low-carbon density ecosystem

China has set a carbon-neutrality target for 2060; carbon sinks are vital tools to meet this target. China is leading the effort in greening the world through the restoration of low-carbon density ecosystems (LCDEs). The potential carbon sinks of LCDEs provide opportunities for carbon trading projects that make cash benefits accessible to the owners, thereby incentivizing ecosystem restoration. Unfortunately, carbon trading in LCDEs has, to date, been unsuccessful in China. Therefore, it is important to identify the barriers in the development of carbon trading projects in LCDEs.

This study aimed at creating a feasible model for carbon trading in LCDEs in China. We first accounted for the carbon sink of LCDEs based on field sampling of 169 quadrants and 3,471 plants. Thereafter, we investigated the trade-off between the cost and efficiency of carbon projects in LCDEs. Finally, we explored the feasibility of the corresponding carbon sink potential by considering carbon price fluctuations and public–private partnership models.

The main findings were as follows: (i) Carbon trading in LCDEs is not economically feasible at the current market price of carbon. In the pilot case, the LCDE carbon trading could only recover 41.72% of the project cost. This partially explains the scarcity of carbon trading for LCDEs in the current emission trading scheme; (ii) A benefit transfer model is essential, wherein the costs of ecosystem restoration are paid by the central government, and the benefits of carbon trade are transferred to the owners of LCDEs, providing sufficient incentives for the owners to participate in carbon trading.

Policy implications. Given the scarcity of large-scale organisations and expertise, carbon trading in low-carbon density ecosystems (LCDEs) should not be treated as a purely commercial project. A public–private partnership network is a suitable model for engaging stakeholders to complete the carbon trading process in LCDEs. For the success of carbon trading in LCDEs, viable carbon prices and transfer of benefits from public investments are policy issues that need to be further explored. Our findings provide a policy basis for the Chinese government to mobilise more LCDE owners to enter the carbon market and achieve carbon-neutrality.

Methods
The Bureau of Forestry of local government provided restoration project documentation and official statistics on grassland restoration. Shrubs (Caragana) were planted as degraded grassland restoration. The area contained a total of 10,467.73 ha of Caragana, and shrubs were planted on 923 plots of land in Siziwang Banner from 2005 to 2013. Some interviews were conducted with the grassland owners. Some face-to-face interviews were conducted with local government officials about the current status of grassland, the role of local governments, degraded grassland restoration investments, and awareness of carbon trade.

中国已确立2060年碳中和目标，碳汇是达成该目标的核心支撑手段。中国正通过修复低碳密度生态系统（Low-Carbon Density Ecosystems，LCDEs）引领全球绿色转型进程。低碳密度生态系统的潜在碳汇可为碳交易项目创造机遇，使生态所有者能够获取现金收益，进而激励生态修复工作。但截至目前，中国的低碳密度生态系统碳交易尚未取得实质性成功。因此，明确制约低碳密度生态系统碳交易项目发展的瓶颈因素具有重要现实意义。

本研究旨在为中国低碳密度生态系统碳交易构建可行实践模式。研究首先基于169个样方、3471株植物的野外采样数据，核算了低碳密度生态系统的碳汇量；随后分析了低碳密度生态系统碳项目的成本与效率权衡关系；最后结合碳价格波动与公私合作伙伴关系（Public-Private Partnership，PPP）模式，探讨了对应碳汇潜力的实现可行性。

本研究核心结论如下：（1）以当前碳市场价格测算，低碳密度生态系统碳交易不具备经济可行性。在本次试点案例中，低碳密度生态系统碳交易仅能收回41.72%的项目建设与运营成本，这在一定程度上解释了当前碳排放权交易体系中低碳密度生态系统碳交易稀缺的现状；（2）构建收益转移模式至关重要，即由中央政府承担生态修复成本，将碳交易收益转移至低碳密度生态系统所有者，为其参与碳交易提供充足激励。

政策启示层面。鉴于大规模组织资源与专业人才的稀缺性，低碳密度生态系统碳交易不应被视为纯商业性项目。公私合作伙伴关系网络是吸引多元利益相关方参与低碳密度生态系统碳交易全流程的适宜模式。要推动低碳密度生态系统碳交易取得成功，合理的碳价格机制与公共投资收益转移路径是亟待进一步探索的核心政策议题。本研究结论可为中国政府动员更多低碳密度生态系统所有者进入碳市场、助力实现碳中和目标提供科学政策依据。

研究方法
当地林业和草原主管部门提供了生态修复项目文档与草原恢复官方统计数据。本研究通过种植锦鸡儿属（Caragana）灌木开展退化草原修复工作。研究区域内锦鸡儿种植总面积达10467.73公顷，2005年至2013年间，在四子王旗的923块地块上完成了灌木种植工作。研究团队对草原所有者开展了访谈调研，同时与当地政府官员进行了面对面访谈，访谈内容涵盖草原现状、地方政府职能定位、退化草原恢复投入情况以及对碳交易的认知程度。