The Data Behind Our FT Analysis: A Technical Breakdown of what Environmental Degradation means for the Stability of Britain’s Public Finances
Author: Robert Oates
Role: Royal Chartered Biologist; Founder & CEO, Arbtech
In a recent letter I wrote to the Editor and was published in the Financial Times (FT), I argued that weakening environmental protections should not be treated purely as an ecological issue. It is also a fiscal one.
The core point was simple: environmental degradation ultimately affects the productive capacity of an economy. When productive capacity declines, economic growth weakens. And when growth weakens, the stability of public finances comes under pressure.
This companion piece sets out the data and reasoning behind that argument in more detail.
The analysis draws primarily on research from the University of Oxford and the Green Finance Institute on nature-related economic risk, alongside fiscal sensitivity analysis published by the Office for Budget Responsibility (OBR). It also draws on wider evidence around natural capital and ecosystem decline.
What follows is not a prediction of economic collapse, nor a precise forecast of future GDP. Instead, it explains how environmental degradation can translate into measurable macroeconomic and fiscal risk.
From ecological decline to fiscal risk
The argument rests on a chain of relationships that is well understood in economics.
Environmental degradation reduces the natural systems that support economic activity – things like fertile soils, reliable water systems, flood protection, and biodiversity.
When those systems weaken, productivity falls in sectors that depend on them. Lower productivity translates into slower economic growth. Slower growth reduces government revenues and increases the difficulty of managing public debt.
In short, environmental degradation does not stay in the environmental column of the policy spreadsheet. It eventually appears in the fiscal one.
The modelling behind the GDP risk estimates
The headline figure cited in the FT letter – that severe nature degradation could place 6–12% of UK GDP at risk over the coming decade – comes from modelling undertaken by researchers at the University of Oxford working with the Green Finance Institute.
The work examines how dependent different sectors of the economy are on ecosystem services such as pollination, soil health, water regulation and climate stability.
The methodology broadly follows four steps:
- Identifying which ecosystem services underpin particular economic sectors
- Mapping how dependent those sectors are on those services
- Modelling degradation scenarios ranging from moderate to severe
- Estimating the proportion of sectoral value that could be affected
The sectors considered include agriculture, construction, infrastructure, manufacturing, water supply and finance, among others. Importantly, the modelling considers not only environmental decline within the UK but also exposure through global supply chains. The UK economy is deeply interconnected with ecological systems abroad, particularly through food imports and raw materials.
A key point here is that this is scenario modelling rather than a forecast. The 6–12% figure represents the scale of potential economic exposure under defined degradation pathways. It does not mean that GDP will suddenly fall by that amount.
However, even much smaller effects on trend growth can have meaningful fiscal consequences over time.
Why growth matters so much for public finances
The Office for Budget Responsibility regularly emphasises how sensitive the UK’s debt trajectory is to small changes in economic growth.
Public debt evolves according to a fairly straightforward dynamic: governments borrow to cover deficits and the stock of debt accumulates alongside interest payments. But the sustainability of that debt is measured relative to GDP. If economic growth slows, two things happen simultaneously.
First, tax revenues grow more slowly because income, profits and consumption expand less quickly. Second, the debt-to-GDP ratio rises mechanically because the denominator – the size of the economy – is growing more slowly.
Even relatively modest differences in long-term growth assumptions can therefore lead to dramatically different debt trajectories. For example, if trend growth were persistently 0.5–1 percentage point lower than expected over a decade, the cumulative impact on the debt ratio would be substantial.
The transmission mechanisms
Environmental degradation affects the economy through several practical channels. Declining soil quality can reduce agricultural productivity. Loss of natural floodplains increases the economic damage from extreme weather. Pollinator decline affects crop yields. Water stress can constrain industrial production.
These are not abstract ecological problems; they have direct implications for sectors that contribute to GDP. From a fiscal perspective, the effects appear on both sides of the government balance sheet.
Lower growth reduces tax receipts from income tax, corporation tax and VAT. At the same time, environmental decline can increase public spending, for example on flood defences, agricultural support, disaster recovery or health impacts associated with environmental stress.
The result is a combination of lower revenues and higher expenditure pressures.
How markets might respond
Financial markets ultimately care about long-term economic capacity.
If investors begin to view a country’s growth prospects as structurally weaker – whether due to demographics, productivity issues, or environmental decline – they may demand higher returns for holding its debt. In practical terms, that means higher government borrowing costs.
Even relatively small increases in gilt yields can translate into very large increases in annual debt servicing costs once they filter through the stock of outstanding debt.
This is one of the reasons the OBR repeatedly stresses how closely fiscal sustainability is tied to long-term growth assumptions.
Domestic degradation and global exposure
An important finding of the Oxford and Green Finance Institute work is that a significant share of the UK’s nature-related economic exposure comes from overseas ecosystems.
The UK imports a large share of its food, timber, and agricultural inputs. Environmental degradation in other countries can therefore feed into the UK economy through supply chains, commodity prices and trade disruptions.
In other words, protecting domestic ecosystems alone would not eliminate exposure. The UK economy is embedded in global ecological systems.
The underlying issue: natural capital
At the heart of this discussion is the concept of natural capital.
Natural capital refers to the stock of natural assets – soils, forests, wetlands, biodiversity, water systems – that generate the ecosystem services on which economies depend.
When these assets are degraded, the services they provide weaken. Unlike financial capital, natural capital often regenerates slowly and sometimes not at all. Soil formation, for example, can take centuries. Species extinction is permanent. Damaged peatlands can take decades to recover.
That is why the analogy with fiscal policy mistakes has limits. Governments can reverse a tax cut quickly. They cannot restore depleted soils or extinct species with a budget announcement.
Uncertainty cuts both ways
Like all scenario modelling, the analysis described here depends on assumptions.
Sectoral dependencies may be incomplete. Ecological interactions are complex. Climate change may amplify impacts in ways that current models cannot fully capture.
But uncertainty does not mean the risk is negligible. In many cases, it may mean the opposite: that the full scale of potential impacts is not yet fully understood.
The broader implication
The purpose of the FT letter was not to suggest that environmental decline will automatically trigger a fiscal crisis.
Rather, it was to highlight that environmental policy and fiscal stability are more closely connected than they are often treated in political debate.
If ecological systems underpin economic productivity – and the evidence increasingly suggests they do – then sustained environmental degradation becomes a macroeconomic issue.
And once it becomes a macroeconomic issue, it inevitably becomes a fiscal one. Understanding that connection is essential if the UK is to think seriously about long-term economic resilience.
