Does China's pathway to carbon neutrality require the integration of land-based biological negative emission solutions with geochemical and chemical alternatives?

Abstract

Carbon dioxide removal (CDR) is a necessary measure to achieve global climate targets. However, each CDR approach has potential trade-offs and spillover effects on the global energy-land-water system. To minimize these negative impacts and achieve climate targets, it has become increasingly important to assess different CDR deployment plans and how they interact with the Earth's system. The existing literature on CDR deployment in China is yet to uncover the potential synergies and trade-offs associated with varying CDR deployment strategies for the country's pathway to carbon neutrality. Here, we model five different CDR approaches categorized under four CDR deployment plans for China's climate aspirations using a variant of the Global Change Assessment Model, GCAM-CDR. Our goal here is not to definitively conclude the superiority of any specific CDR deployment plan for China's climate ambitions but instead to primarily explore and emphasize the potential implications associated with each group of CDR strategies. We show that China's pursuit of carbon neutrality solely through land-based biological CDR methods could result in reduced fossil fuel consumption, greenhouse gas emissions, and total air pollutants. However, an integrated approach that combines both land-based biological and geo/chemical CDR strategies could enhance the economic feasibility of achieving China's climate objectives. Moreover, it could reduce land and water requirements for energy generation and negative emissions, thereby mitigating the pressure on food croplands and other sustainability issues. Compared with an integrated approach, relying solely on land-based biological CDR processes for China's carbon neutrality goal could lead to a cumulative reduction in residual GHG emissions by at least 2 GtCO2e over the next four decades (in 5-year intervals) as China progresses towards carbon neutrality. On the other hand, the mitigation cost of relying exclusively on land-based biological CDR processes for China's carbon neutrality goals could be approximately 30 % higher than that of an integrated approach (on an annual average basis). In conclusion, China's policymakers and stakeholders should carefully assess different combinations of diverse CDR approaches, considering the associated impacts on the country's energy-land-water system and policy costs, to make informed decisions that help maximize benefits and minimize negative consequences in pursuit of carbon neutrality goals.