As we approach COP30 with its focus on reducing emissions, I want to set out a clear view of how natural and man-made landscapes can deliver meaningful climate gains under two complementary principles: reduce emissions at source and remove potent greenhouse gases from the atmosphere.
My work at Cambridge, particularly with the Centre for Landscape Regeneration and the Land Use for Net Zero Hub, concentrates on practical pathways in land management to help with emissions reduction and nature recovery, alongside the economics and governance that determine what is actually feasible.
Dr Shaun Fitzgerald OBE
“Reducing nitrous oxide … optimising peat water levels … are not silver bullets. They are components of a coherent strategy that accepts the biophysical realities of managed landscapes and the economic realities of those who work them.”
Agriculture’s reliance on synthetic fertilisers is central – fertilisers have underpinned the productivity gains that feed billions, yet their production and use contribute significantly to greenhouse gas emissions, with fertiliser-linked sources accounting for roughly five percent of the global total today.
The problem is not only how much we make but how we use it. When nitrogen is applied in excess or at the wrong time, we see runoff and the release of nitrous oxide. Although present at about 0.3 parts per million compared with carbon dioxide at roughly 420 parts per million, nitrous oxide has a global warming potential around 264 times that of carbon dioxide over 20 years, making it a disproportionately important target for mitigation.
Technically the prescription is simple: apply fertiliser little and often, closely matched to crop demand, to reduce losses. The difficulty is economic and logistical. Precision regimes imply more labour, equipment and monitoring, which raises costs in a sector that must keep food affordable. Farmers are sophisticated business people already operating on tight margins. If society wants climate benefits from changes in fertiliser practice, then we must answer the unavoidable question: who pays.
At the Centre for Landscape Regeneration we are tackling issues related to land management collaboratively, combining rigorous data on biodiversity, economics and where and how emissions arise as well as working closely with farmers and land managers who understand the land, and who are essential to any solution. Our work is focussed on the Cambridgeshire Fens, the Cairngorms and the Lake District.
Peatland management in the Fens shows how delicate these trade-offs are. Lowland peat north of Cambridge is immensely productive, supplying a large share of the United Kingdom’s salad crops. Decades of drainage have exposed peat to oxygen, accelerating oxidation that releases substantial carbon dioxide and causing the land surface to subside by metres.
Raising water tables can slow oxidation and carbon loss, but fully flooding peat risks higher methane emissions under anaerobic conditions. Methane is extremely potent on short time horizons, roughly 120 times more warming than carbon dioxide over very short periods and about 30 times over a century.
There appears to be an optimum water level that minimises total warming by balancing carbon dioxide and methane fluxes. Leaving a small portion of peat unsubmerged can support methanotrophs—microbes that consume methane—and convert it into carbon dioxide which, though still a greenhouse gas, has a lower warming impact than methane.
Determining that optimum is not purely a scientific exercise. It intersects with flood risk, crop viability and day-to-day land operations. Higher water tables can increase the risk of crop loss, bringing us back to compensation, insurance and responsibility. These practicalities are decisive for adoption at scale.
Alongside reduction, I see methane removal as a promising frontier especially in man-made landscapes – better known as the built environment. Given methane’s high near-term potency and relatively short atmospheric lifetime, removing methane can yield rapid climatic benefits. New technologies aim to catalyse methane oxidation or enhance natural sinks, potentially in ways that integrate with operation of buildings.
The scholarly task is to validate these approaches under realistic conditions, quantify co-benefits and trade-offs, and design governance and cost-sharing so that deployment is responsible and fair to all.
Returning to natural landscapes and figuring out if there are ways to reduce emissions, the unifying method I use is a mass-balance mindset grounded in measurement. If crops remove atoms of nitrogen and micronutrients, we must replenish them in ways that minimise emissions and loss pathways.
If peatlands store carbon when waterlogged but risk methane release when saturated, water levels must be managed for the least-warming outcome over relevant time horizons.
Progress depends on aligning scientific insight with economic instruments and risk-sharing. Farmers manage multiple hazards already, from weather variability to market swings. Asking them to take on new operational risks—such as higher water tables—without clear compensation will fail. Insurance may have a role, since society benefits from avoided climate damages, but translating distributed long-term gains into near-term local incentives remains the crux.
My perspective is deliberately practical. Reducing nitrous oxide through precision nutrient management and optimising peat water levels to limit net warming from natural landscapes, and advancing methane removal through the application of new catalysts in the built environment are not silver bullets. They are components of a coherent strategy that accepts the biophysical realities of managed natural landscapes and the practical needs of the built environment, and the economic realities of those who work them. The work ahead is as much about fair cost allocation and institutional design as it is about agronomy and atmospheric chemistry.
