Climate mitigation potential of natural climate solutions and clean energy on The Nature Conservancy properties in California, USA

RESEARCH ARTICLE Climate mitigation potential of natural climate solutions and clean energy on The Nature Conservancy properties in California, USA Kristen N. WilsonID1*, Daniel W. Salzer2, Michelle C. Passero1 1 The Nature Conservancy, San Francisco, California, United States of America, 2 The Nature Conservancy, Portland, Oregon, United States of America * kristen.wilson@tnc.org Abstract Natural climate solutions (NCS) and transitioning to clean energy can reduce greenhouse gases and contribute to mitigating climate change. Private landowners with large holdings, such as conservation organizations like The Nature Conservancy, have set ambitious goals to reduce net emissions and increase sequestration on their lands by implementing NCS. We assessed the potential carbon dioxide-equivalent (CO2e) reduction from feasible NCS, specifically implementing new restoration and agricultural management activities, and tran- sitions to clean energy on The Nature Conservancy, California chapter’s fee-owned and conservation easement properties. We compared the total CO2e reduction from potential new NCS activities to the impact from ongoing NCS activities, the chapter’s 2030 goal, and the state’s reduction goal for natural and working lands to understand how the organization can contribute to climate mitigation. We found that implementing NCS on 37 fee-owned properties (63,175 MTCO2e year –1) and clean energy on 10 fee-owned properties (488 MTCO2e year –1) combined would not reach the chapter’s 2030 goal (72,000 MTCO2e year

–1), and there can be tradeoffs between maximizing CO2e reduction and protecting conser- vation values. However, ongoing changes to forest management on a single conservation easement property, where another non-profit harvests timber and sells carbon credits, cur- rently contributes 147,749 MTCO2e year –1, more than two times the 2030 goal and repre- senting 7.4% of the state’s annual goal. Our results suggest that The Nature Conservancy, California chapter would need to implement NCS on some of the conservation easements or consider future land protection deals with carbon rich ecosystems or high impact NCS to reach their CO2e reduction goal. Introduction Implementing natural climate solutions (NCS) and transitioning to clean energy are essential to reduce greenhouse gas emissions to, and increase removal from, the atmosphere. Com- bined, these actions can help to mitigate the climate crisis. NCS are land management activities that increase carbon sequestration and storage or avoid greenhouse gas emissions by PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0311195 October 21, 2024 1 / 14 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Wilson KN, Salzer DW, Passero MC (2024) Climate mitigation potential of natural climate solutions and clean energy on The Nature Conservancy properties in California, USA. PLoS ONE 19(10): e0311195. https://doi.org/10.1371/ journal.pone.0311195 Editor: Mattias Gaglio, University of Ferrara, ITALY Received: May 23, 2024 Accepted: September 14, 2024 Published: October 21, 2024

Copyright: © 2024 Wilson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All data is available in an online repository https://osf.io/vmh82/. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist.