On 7 September — Clean Air Day — the United Nations published the most thorough attempt yet to answer a simple question: is cleaning up the air and the climate worth the money? The answer was yes, by a wide margin. A shadow carbon price is the tool that lets one company act on that finding without waiting for anyone else.

The short version

• The UN costed 25 proven actions that cut air pollution and greenhouse gases at the same time. Every $1 spent returns about $15. Count only hard cash — hospital bills avoided, workers not off sick — and it still returns $4.
• In Southeast Asia the return is 13:1, roughly four times Europe’s. The payoff is biggest where the air is dirtiest.
• About half that value comes from cleaner air, not a cooler planet — and it arrives within years, not decades.
• The technology exists and the money exists. What’s missing is speed, and the main thing slowing everyone down is that nobody has good enough numbers to act on with confidence.
• A shadow carbon price is how a single business turns all of this into a decision it can make on Monday morning.

What the UN Actually Found

Burning fossil fuels does two kinds of damage at once. It warms the planet — slowly, globally, and mostly in the future. And it fills the air with tiny particles that people breathe — quickly, locally, and right now. These are usually treated as two separate problems by two separate government departments with two separate budgets. The argument is that they are one problem with one set of fixes, and that we have been badly underestimating the payoff by pricing them separately.

When you count both together, the numbers change dramatically. You can read the full assessment on the UNEP report page.

Three details make the finding hard to argue with.

The conservative version is still excellent

The headline is 15:1 — spend a dollar, get fifteen back. Some of that fifteen is what economists call non-market value: what it’s worth to not have asthma, or to live longer. Reasonable people argue about how to put a number on that.

So strip all of it out. Count only money that moves: healthcare spending avoided, productivity gained, physical damage prevented. The return is still $4 for every $1. That is a better return than most infrastructure a government will ever build.

It costs less than things we already pay for

The whole package runs about 0.7% of global GDP over the next decade. That sounds enormous until you set it beside the bills already being paid: the world spends 2.18% of GDP subsidising fossil fuels, 3.5% on education and 9.3% on healthcare.

In other words, the ask is roughly a third of what governments already spend making the problem cheaper.

It pays back within a decade

By 2035, the money saved on healthcare and gained in productivity from cleaner air alone is greater than the total cost of all 25 actions — before counting a single dollar of anything harder to measure. This is not a “grandchildren will thank you” investment. It clears its own cost inside ten years.

Why the Numbers Are Bigger in Southeast Asia

The global average hides an enormous spread, and it runs the opposite way to where most of the pressure comes from.

Southeast Asia returns roughly four times what Europe does. Not because Asian companies are better at this — because the return is largest where the damage is worst. Regions carrying the heaviest pollution burden have the most harm available to avoid.

That flips a familiar story. Climate rules have mostly arrived in Asia as imports: European supply-chain requirements, international disclosure standards, lenders applying frameworks written somewhere else. Imported rules feel like a cost. A 13:1 return is not a cost — it is a domestic economic opportunity that belongs to the operator, not the regulator.

Two findings sharpen this for anyone making a business case here.

Clean air is half the value, and it arrives first

The economic value of avoided air pollution damage is larger than the value of avoided climate damage in the early years, and it is still around 45% of the total in 2100.

We normally describe cleaner air as a nice side effect of climate action. It is closer to half the reason to act — and it is the half that shows up inside a normal business planning horizon, in sick days not taken and hospital admissions that don’t happen.

For anyone building the internal case for an energy upgrade, that is useful. Leading with health and productivity rather than tonnes of CO₂ is now the position with the stronger evidence behind it.

Waiting doesn’t just delay the benefit — it destroys some of it

The report’s clearest example is Delhi. Meet India’s air-quality standards on schedule from 2026, and Delhi’s cumulative pollution exposure falls 20% by 2040. Delay by eight years — the global average — and the same policy delivers 10%.

Same rules, same endpoint, half the benefit. The difference is gone permanently, because the people who developed asthma during the delay have already developed it. You can reschedule a construction project. You cannot reschedule the years someone spent breathing.

So What Is a Shadow Carbon Price?

Here is where a global report becomes something a single company can use.

A shadow carbon price is a pretend price with real consequences.

You decide that from now on, every investment proposal inside your business carries an extra line: the cost of the pollution it creates, at a price you set yourself. Nobody charges you this. No money moves. You simply put it in the spreadsheet next to the capital cost and the running cost.

Then you watch what happens to the ranking.

A boiler upgrade that looked mediocre on energy savings alone moves up the list once you count the emissions it avoids. A bigger, more visible expansion project moves down. Nothing about the engineering changed. The comparison did — because you widened what the comparison counts.

This is exactly the move the UN made, just at a different scale. The 15:1 exists because the authors counted damage that normal accounting ignores. And they counted more of it than anyone had before: earlier studies priced only deaths from air pollution, while this one priced illness too. Roughly one in five cases of major chronic disease traces back to air pollution — 22% of childhood asthma, 21% of chronic lung disease, 20% of heart attacks and strokes.

Widening the boundary of what gets counted is what made the answer four times bigger than previous estimates. A shadow carbon price does the same thing inside one company’s books.

A Real Example: Thai Airways

This is not theoretical, and the clearest example in the region is an airline.

In 2025, Thai Airways International built the THAI Sustainability Platform with Evercomm and implementation partner Teo Hong Silom. Most of it is unglamorous plumbing: emissions across the whole business measured automatically to ISO 14064-1 and Thai national standards, pulled directly from the airline’s finance, HR and operations systems, so that every report the airline files comes from the same underlying dataset instead of four different spreadsheets.

But sitting on top of that plumbing is a shadow carbon price. THAI applies an internal carbon cost to its own investment decisions, tracked alongside normal financial measures like NPV and IRR through NXPlan. Emissions reduction projects get ranked in the same language the finance team already uses for everything else.

Two things make this smart rather than merely virtuous.

It is a rehearsal for a bill that is coming. Carbon pricing regimes across Asia are still forming. A company that has been shadow-pricing for three years by the time a real price arrives has already made three years of correctly-ranked decisions. Everyone else starts from zero, under time pressure.

And it only works because the numbers are trustworthy. THAI’s platform can trace any published figure back through every conversion and assumption to the original document or meter reading, with third-party verifiers given direct access to check it.

That matters more than it sounds. You cannot price a tonne you cannot trace. Apply a shadow carbon price to estimated emissions and you get a confidently ranked list of the wrong projects — which is arguably worse than not ranking them at all.

Two Ways to Hit a Target. Only One Pays You Back

There is a second lesson in Jebsen & Jessen Group’s 2026 sustainability report, and it is easy to miss.

Across eight business units in fourteen countries, the group stayed carbon neutral on its direct emissions while total energy use rose 12.5% — because it was acquiring companies. It did that in two very different ways at once.

It bought 50,053 tonnes of carbon credits. And it did structural work: solar installed across its Packaging business, and in Vietnam, 11,384 tonnes of biomass fuel replacing coal at a manufacturing site.

In an annual report, both look the same — tonnes handled. Under a shadow carbon price, they look nothing alike. Credits are a recurring payment that returns nothing to the business. The Vietnam fuel switch permanently changes what that site emits, cuts local air pollution and CO₂ at the same time, and is precisely the kind of action the UN report identifies as highest-return in developing Asia.

One is an expense. The other is an investment with a measurable return. Telling them apart requires data at the level of the individual site — and that distinction is invisible in a group-level total.