Aligning natural climate solutions with mitigation policies for low-cost carbon neutrality: insights from the Qinghai–Tibet Plateau

Abstract To limit global warming to below 1.5 °C–2 °C, more than 140 countries have pledged carbon neutrality. However, many less-developed countries and regions face economic constraints and often suffer from severe ecosystem degradation, which jointly hinder their ability to meet these commitments. Here, we use the Qinghai–Tibet Plateau (QTP), a less-developed region that has experienced ecosystem degradation, as a case study. We use a novel multi-scenario modeling framework to assess the impact of different combinations of natural climate solutions (NCS) and carbon emission reduction policies (CERPs) on carbon neutrality and associated costs. Our findings show that carbon neutrality was achieved on the QTP by 2020, with a surplus of 18.16 MtCO 2 yr −1 . However, without CERPs, carbon emissions on the QTP are projected to increase fivefold by 2060 compared with 2020 levels. Even with stringent NCS, a shortfall of nearly 375.34 ± 99.05 MtCO 2 yr −1 in maintaining carbon neutrality remains in 2060. If CERPs are implemented without NCS, the cost of maintaining carbon neutrality in 2060 is estimated at USD 199.07 ± 25.96 billion during 2020–2060. Notably, integrating NCS with CERPs reduces costs by nearly half (USD 111.51 ± 21.48 billion). Furthermore, the integration of aggressive CERPs and NCS on the QTP could contribute a further additional surplus by 2060 toward national carbon neutrality goals at a pretty low carbon price. Our research highlights that combining NCS with CERPs yields greater climate benefits at significantly lower costs, providing potential pathways for financially constrained regions to enhance climate mitigation, especially when supported by international climate finance and cooperative mechanisms.