The Net-Zero Emissions Challenge: Quantifying unintended climate feedbacks from large- scale deployment of land-based CO2 removal strategies

This project addresses the urgent challenge of climate change by exploring land-based carbon dioxide removal (CDR) strategies, such as afforestation/reforestation, wetland restoration, and enhanced rock weathering (applying crushed basalt rocks to soils to accelerate natural carbon capture). While these methods hold great promise for reducing atmospheric carbon and mitigating climate change, their broader impacts on air quality, ecosystems, and the climate itself remain poorly understood. These knowledge gaps limit their effective and sustainable implementation. Building on findings from the first phase of my UKRI Future Leaders Fellowship, this research will investigate how natural events, like wildfires, and human-driven factors, such as air pollution, influence the effectiveness and durability of land-based CDR strategies. For example, my initial work has shown that atmospheric chemistry and albedo feedbacks (ie, changes in how surfaces reflect sunlight) can reduce the cooling benefits of tree planting by up to 30%. This underscores the need for a deeper understanding of the trade-offs, synergies, and unintended consequences associated with these strategies. The project has three main objectives. First, it will evaluate how disturbances, such as wildfires and air pollution, impact the carbon storage potential of afforestation/reforestation strategies under future climate scenarios. Second, it will assess the effectiveness of combining different land-based CDR strategies, such as enhanced rock weathering with afforestation/reforestation, and bioenergy crops, identifying ways to maximize benefits while minimizing trade-offs. Third, it will focus on land-use strategies specific to the UK, providing detailed assessments of their air quality and climate impacts and their contributions to achieving the country’s Net Zero targets. This project will fundamentally advance the science of land-based CDR strategies by addressing these complex and interconnected questions, providing actionable, science-based recommendations for policymakers and practitioners. For the UK, the findings will support Clean Air Strategies, sustainable land management, and Net Zero commitments. Globally, the research will inform upcoming Intergovernmental Panel on Climate Change (IPCC) assessments and guide international climate negotiations, including the United Nations Framework Convention on Climate Change COP meetings. Collaborations with leading organizations such as the National Center for Atmospheric Research (NCAR), WWF, and DESNZ will ensure the research is grounded in real-world challenges and directly applicable to policy and practice. Partnerships with industry, including UNDO and the Future Forest Company, will translate findings into scalable solutions for land-based carbon removal, bridging science, policy, and implementation. An essential aspect of this fellowship is training the next generation of Earth scientists. The project will provide early-career researchers with opportunities to develop expertise in advanced Earth system modelling, big data analysis, and interdisciplinary collaboration. Through professional development programs and partnerships with leading institutions, team members will gain critical skills to integrate science with policy and practice, equipping them to tackle the global challenges of climate change and air quality.