Illustration of trace gas monitoring using a spectrometer. Public domain.

How do we know that UK GHG emissions are really falling?

Mar 28 2025

Beyond the headlines, emissions monitoring professionals must learn (and continually update) methodologies to assign emissions more accurately.

By Jed Thomas

The UK’s territorial greenhouse gas (GHG) emissions fell by 3.5% in 2024, reaching levels not seen since the 1870s.

The last coal-fired power station shut down, renewables passed the 50% mark in electricity generation, and EV uptake surged.

For environmental professionals, especially those involved in emissions monitoring, these developments are a milestone.

But they also raise an important question: are we measuring the right thing?

The limits of calculating territorial emissions

UK emissions figures, including those reported by the Department for Energy Security and Net Zero (DESNZ), follow the internationally recognised territorial methodology.

This counts emissions released within national borders — from power plants, vehicles, industry, and buildings. It’s a robust system, supported by direct measurements and well-developed inventory protocols.

However, territorial accounting omits a significant source of carbon emissions: those generated abroad in the production of goods and services consumed in the UK.

This includes industrial emissions from steel plants in Asia, CO₂ from shipping, and the upstream footprint of electronics, textiles, chemicals, and processed foods imported into the country.

For professionals using environmental monitoring tools, this is a critical distinction. Measuring what leaves a UK chimney or tailpipe is essential — but it may no longer capture the majority of our climate impact.

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Is UK carbon footprint actually reducing?

Researchers at the University of Leeds have been publishing consumption-based carbon footprint estimates for the UK since 2011, commissioned by Defra.

These figures combine domestic emissions with the estimated CO₂ embedded in traded goods and services, using multiregional input-output (MRIO) models.

According to their latest data, the UK’s carbon footprint in 2016 was at its lowest level for 20 years — around 10% below 1997 levels.

This is encouraging, but it also highlights a key issue: progress in consumption-based emissions has been slower than in territorial emissions, which fell by 20% over the same period.

That gap is largely due to increased reliance on imports. In 1997, net imported CO₂ made up just 5% of the UK’s footprint; by 2016, it was 20%.

The implication is clear: as domestic emissions monitoring has improved and cleaner energy sources have proliferated, the UK has also offshored a portion of its carbon emissions.

Emissions from UK-consumed goods are increasingly measured — if at all — in other countries.

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Monitoring emissions in a globalised supply chain

For users of environmental monitoring equipment, the challenge is both technical and systemic.

Direct emissions monitoring — from stack testing to ambient air quality sensors — remains essential.

But in a world of globalised production, a growing share of emissions can only be estimated indirectly, via economic modelling, trade flow analysis, and lifecycle assessments.

Multiregional input-output (MRIO) modelling is one of the most sophisticated tools for this task.

It maps global supply chains and assigns emissions based on where goods are made and where they’re consumed.

While not as precise as direct monitoring, MRIO offers the only viable approach to quantifying carbon leakage and the full impact of national consumption.

These models, while powerful, depend heavily on high-quality trade, production, and emissions data from across the globe.

The uncertainties involved are non-trivial, but so are the stakes: without these broader metrics, climate policies risk rewarding offshoring over actual decarbonisation.

Implications for policy — and for monitoring

The UK’s environmental and climate policy framework increasingly depends on accurate, granular emissions data.

Whether through compliance with the UK Emissions Trading Scheme (UK ETS), reporting under SECR (Streamlined Energy and Carbon Reporting), or net-zero transition planning, emissions monitoring is foundational.

But if we continue to base our progress on territorial emissions alone, we may underestimate our real carbon footprint and the global effects of our consumption.

This has policy consequences: some emissions reductions may be statistical illusions driven by trade patterns rather than technological shifts.

It also creates a blind spot for interventions.

Resource efficiency, circular economy strategies, and product standards can all reduce overseas emissions associated with UK consumption — but their impact may be invisible in domestic carbon ledgers.

For the environmental monitoring sector, this is a moment of opportunity.

As monitoring technologies become more sophisticated and data integration improves, there is scope to feed better upstream data into global models, improve estimates of embodied carbon, and ultimately influence a more honest approach to carbon accounting.