Earth LinC station  /  a benchmark of common sense

Carbon
watching

Every year the world puts about 41.6 billion tonnes of CO₂ into a thin shell of air. Roughly half of it stays. This page is not a report — it is an attempt to check whether what we cover is actually what matters.

Figures: 2023–2025 Units: GtCO₂ / GtCO₂e / ppm Sources listed at the end
1958 · 315 ppm pre-industrial 278 ppm 2024 · ~423 ppm
57.1 GtCO₂e

Total greenhouse gases released in 2023 — an all-time record, up 1.3% on the year before.

~50%

Share of our CO₂ that land and ocean still absorb for free. The other half accumulates.

~235 GtCO₂

Remaining budget for a 50% chance at 1.5 °C, from the start of 2025. About six years at today's rate.


00

The question that starts it

A sustainability role inside supply chain and product is mostly a job of coverage. You draw a boundary, you count what's inside it, you improve what you can reach. And then one quiet afternoon the honest question arrives: do we cover the best of what we can cover — and even if we do, is our decarbonization still very limited?

The only way to answer is to zoom out until the company disappears and the planet's ledger is visible. Then zoom back in, and see where your hands actually are.

Writing is not just a record. Writing is thinking. — the brief for this page

01

The planet's balance sheet

Carbon is not a moral quantity, it is an accounting one. Sources in, sinks out, and whatever doesn't balance stays in the air and warms things. Here is the 2024 ledger, in gigatonnes of CO₂ per year.

Sources — what we release

Fossil fuels & cement37.4
Land-use change, mostly deforestation4.2
Total CO₂ emitted41.6

Add methane, nitrous oxide and F-gases and the full basket reaches 57.1 GtCO₂e (2023). CO₂ is about three-quarters of it; methane about 17–18%; N₂O about 6%.

Sinks — what the Earth takes back

Ocean uptake10.6
Land & forest uptake11.4
Left airborne, every year~19.6

That residue is why concentration climbs about 2.4 ppm each year. Nature is subsidising roughly half our emissions — unpaid, unpriced, and not guaranteed.

accumulates for centuries forests, soils — fragile, reversible ocean — bought at the cost of acidity

02

Where it actually comes from

Share of global greenhouse gases by activity. Note what this cut reveals: “energy” is not a sector, it is a verb inside every other sector. Electricity does not appear as its own line — it is folded into the industry, buildings and transport that consume it.

Energy use in industry24.2%Iron & steel, chemicals, cement, machinery, mining, paper, food processing
Agriculture, forestry & land use18.4%Livestock methane, soils, rice, deforestation, burning
Energy use in buildings17.5%Heating, cooling, lighting, cooking — residential and commercial
Transport16.2%Road 11.9% · aviation 1.9% · shipping 1.7% · rail 0.4%
Unallocated fuel combustion7.8%
Fugitive emissions from energy5.8%Leaked and vented methane from oil, gas and coal — invisible, and cheap to stop
Direct industrial process chemistry5.2%Cement clinker 3% · chemicals 2.2% — emitted by the reaction itself, not the fuel
Waste3.2%Landfill methane and wastewater
Energy in agriculture & fishing1.7%

Sector shares: Climate Watch / WRI dataset, as presented by Our World in Data. Cut a different way — by food system rather than by smokestack — food accounts for about 34% of all emissions (Crippa et al., Nature Food, 2021). Both numbers are true. The boundary you choose decides what you see.

Who emits — territorial fossil CO₂

China~31%
United States~13%
India~8%
European Union (27)~6%
Russia~5%
Everyone else~37%

Per person, per year

United States~14 t
China~8 t
European Union~6 t
World average~4.7 t
India~2 t
Compatible with 1.5 °C by 2050<1 t

And on the supply side: a small number of producers dominate. The Carbon Majors database traces roughly 80% of global fossil CO₂ since 2016 to 57 producing entities. Concentration is a problem — and it is also leverage.

03

Why the balance is tipping

The half-that-disappears is the most underrated line in the whole ledger. It is not a policy, it is a favour — and the terms are quietly changing.

The system is not losing balance because one villain got worse. It is losing balance because the inflow grew for two centuries while the outflow stayed roughly the same size — and is now, in places, shrinking.


04

Ten places with real room

Ranked by assessed mitigation potential for 2030, drawn mainly from the IPCC AR6 Working Group III assessment, with IEA and UNEP figures where they are sharper. Percentages are against the 57 GtCO₂e we emitted in 2023 — so you can feel the size honestly. Roughly half of all this potential is available at under US$20 per tonne.

01

Solar power

The cheapest electricity in most of the world, and it scales in months rather than decades. The bottleneck is no longer cost — it is grids, permits and storage.

~4.0 Gt · ≈7%
02

Wind power

Onshore wind is the other pillar of the same displacement: every terawatt-hour it makes is a terawatt-hour of coal or gas that never burns.

~4.0 Gt · ≈7%
03

Stop converting forests and ecosystems

The single largest nature-based lever, and it costs less than restoring what we destroy. Four commodities — beef, soy, palm oil, timber — drive most tropical deforestation, and they all run through somebody's supply chain.

~4.0 Gt · ≈7%
04

Restore ecosystems & sequester carbon in farmland

Reforestation, peatland and mangrove restoration, agroforestry, soil carbon. Slower, reversible, and impossible to skip.

~3.3 Gt · ≈6%
05

Plug fossil methane leaks

The energy sector leaks around 120 Mt of methane a year. About 70% is technically avoidable with existing kit, and roughly 40% at no net cost, because the gas is worth money. Fastest near-term brake on warming that exists.

~2.4 Gt · ≈4%
06

Efficiency and electrification in buildings

Heat pumps, insulation, efficient cooling, better appliances. Unglamorous, distributed across billions of decisions, and about a sixth of all emissions sits here.

~2.2 Gt · ≈4%
07

Shift diets toward plants

Livestock is the biggest single source of agricultural methane. Assessed potential ranges widely (0.7–8 Gt) because it depends entirely on how many people change, not on whether the physics works.

~2.0 Gt · ≈3.5%
08

Cut food loss and waste

Over a billion tonnes of food is wasted each year — around a fifth of what reaches consumers — carrying an estimated 8–10% of global emissions with it. Emissions already spent, for nothing.

~1.9 Gt · ≈3%
09

Electrify transport

More than one in five cars sold worldwide in 2024 was electric. The value only lands fully when the grid behind the plug is clean — sequence matters.

~1.7 Gt · ≈3%
10

Reinvent cement and steel

Together roughly 14–16% of global CO₂, and half of cement's emissions come from the chemistry itself. Clinker substitution, scrap-based electric steel, hydrogen, capture. The hardest tenth on this list — and the one that needs demand-side buyers most.

~1.2 Gt · ≈2%

Assessed total across all mitigation options by 2030: 31–44 GtCO₂e per year — more than half of current emissions. The constraint is not the absence of solutions. It is deployment rate, capital, and who is willing to change a specification.


05

Deep dive: heavy today, heavier tomorrow

Two different questions. Which industries are big? — steel, cement, chemicals, food. Which are accelerating? — a very different list, and the one a product and supply chain role should be watching, because today's small line is next decade's structural problem.

Biggest industrial sources

Food systems, farm to fork~34% of GHG
Iron & steel~7–9% of CO₂
Cement~7–8%
Chemicals & petrochemicals~5–6%
Aluminium~2%
Oil & gas methane (fugitive)~5.8% as CO₂e

The stubborn shape of it

These are the “hard to abate” industries for a physical reason, not a political one: they need extreme heat, they emit from chemistry rather than combustion, their plants last 30–50 years, and their products are traded as commodities where a 10% green premium loses the tender.

Which is exactly why the lever sits with buyers. A steel mill cannot justify a new process for a market that does not exist yet. Purchase orders create that market.

▲ Fastest structural growth

Data centres & AI

~415 TWh

Around 1.5% of world electricity in 2024, projected by the IEA to roughly double toward ~945 TWh by 2030. The load is new, concentrated, and growing faster than clean supply in most grids.

▲ Rebounded and rising

Aviation

~1.9%

Of global emissions, and back above pre-pandemic levels. Sustainable fuels remain a fraction of a percent of jet fuel used. No electrification path for long haul this decade.

▲ Locked-in demand

Shipping

~1.7%

Roughly 1 Gt a year, carrying 80%+ of world trade. Ships built today burn fuel in 2050. Every product with an ocean leg owns a slice of this.

▲ Growing with income

Cooling

~2×

Space-cooling demand is on track to multiply by mid-century as heat and incomes rise. A warming feedback made of appliances — and of refrigerant gases hundreds of times stronger than CO₂.

▲ The oil industry's plan B

Plastics & petrochemicals

~5–6%

The IEA has called petrochemicals the largest driver of future oil demand growth. As fuel demand peaks, feedstock demand is meant to replace it — inside packaging, textiles and components.

▲ Fast-fashion physics

Textiles

2–8%

Estimates vary wildly by boundary — which is itself the finding. When a sector cannot agree on its own footprint within a factor of four, it cannot yet manage it.


06

So where are your hands?

Here is the number that reframes a supply chain job. CDP finds that for the average company, supply chain emissions are around 11.4 times its direct operational emissions. Which means a perfect, fully renewable, zero-emission headquarters can still be a rounding error.

Coverage is the real work. Not because scope 3 is fashionable, but because that is where the tonnes physically are — in the steel of a housing, the polymer of a casing, the freight lane, the farm three tiers upstream that nobody has ever visited.

What moves tonnes, in order

Design — material choice, mass, lifetimebefore anything
Specification & procurement standardscreates markets
Supplier energy: electricity contracts, heatlargest single block
Logistics mode and load factorfast, cheap wins
Use-phase efficiency of the productoften the majority
End of life, recovery, reusecloses the loop

Honest limits worth naming

Most corporate footprints are built from industry-average emission factors, not measured data. Averages cannot detect improvement — which means a lot of reported reduction is boundary movement, not physics.

Offsets do not cancel a tonne emitted; at planetary scale the removal capacity to match our emissions simply does not exist yet. Reduce first, and be precise about what the residual really is.

0 tonnes CO₂
Released worldwide since you opened this page — arithmetic, not prophecy: 41.6 GtCO₂ a year works out at roughly 1,318 tonnes every second.

07

Questions I could not close

The reading was the easy half. These are the ones still open — offered so that you add yours, rather than accept mine.

Q

If half of our emissions are absorbed for free by land and ocean, and that half is weakening, should every target be measured against a shrinking allowance rather than a fixed one?

Q

Our reported footprint uses average emission factors. If a supplier genuinely halved their process emissions tomorrow, would our number move at all? If not, what are we actually managing?

Q

Which single specification in our product — one material, one thickness, one tolerance — carries the most tonnes? Do we even know its name?

Q

Fossil methane abatement is 40% free and among the fastest brakes on warming. Why does almost no corporate roadmap contain a methane line?

Q

We buy compute the way we once bought freight — invisibly, by the unit. What happens to our footprint when AI workloads triple?

Q

Are we optimising the product we sell, or the product the world will actually need? Efficiency inside a growing volume can still add tonnes.

Q

If our scope 3 is 11 times our scope 1 and 2, why is 11 times the effort not going there?

Q

What would we have to stop making entirely — and who inside the company is allowed to ask that out loud?

None of these need an answer today. They need an owner, a date, and one measurable next step. That is how action flows.


08

Sources

Every figure above traces to one of these. Where estimates differ between bodies, the range is shown rather than the flattering end. Check them — disagreeing with a number is a better outcome than believing it.

  1. Global Carbon Project — Global Carbon Budget. Annual fossil, land-use, ocean and land sink figures; remaining carbon budget.
    globalcarbonbudget.org
  2. NOAA Global Monitoring Laboratory — Trends in Atmospheric CO₂. Global mean concentration and annual growth rate.
    gml.noaa.gov/ccgg/trends/global.html
  3. UNEP — Emissions Gap Report 2024. 57.1 GtCO₂e total for 2023; warming trajectories; required 2030 cuts.
    unep.org/resources/emissions-gap-report-2024
  4. Our World in Data — Emissions by sector. Sector and sub-sector percentage breakdown (Climate Watch / WRI data).
    ourworldindata.org/emissions-by-sector
  5. Climate Watch (WRI) — Historical GHG Emissions. Country, gas and sector data explorer.
    climatewatchdata.org/ghg-emissions
  6. IPCC AR6 Working Group III — Mitigation of Climate Change. Assessed 2030 mitigation potentials and costs by option.
    ipcc.ch/report/ar6/wg3/
  7. IEA — Global Methane Tracker. Energy-sector methane volumes and abatement potential.
    iea.org/reports/global-methane-tracker-2024
  8. IEA — Energy and AI. Data-centre electricity demand today and to 2030.
    iea.org/reports/energy-and-ai
  9. IEA — Global EV Outlook 2025. Electric vehicle sales share.
    iea.org/reports/global-ev-outlook-2025
  10. IEA — Global Energy Review 2025. Energy-related CO₂ and demand trends.
    iea.org/reports/global-energy-review-2025
  11. IEA — Cement and Steel sector pages. Process emissions and technology pathways.
    iea.org/energy-system/industry/cement  ·  iea.org/energy-system/industry/steel
  12. IRENA — Renewable Capacity Statistics 2025. Record renewable capacity additions.
    irena.org/Publications/2025/Mar/Renewable-capacity-statistics-2025
  13. Crippa et al. (2021), Nature Food — Food systems are responsible for a third of global anthropogenic GHG emissions.
    nature.com/articles/s43016-021-00225-9
  14. UNEP — Food Waste Index Report 2024. Volume of food wasted and associated emissions share.
    unep.org/resources/publication/food-waste-index-report-2024
  15. CDP — Supply Chain programme. Supply chain emissions relative to operational emissions.
    cdp.net/en/supply-chain
  16. The State of Carbon Dioxide Removal. Current conventional and novel CDR volumes.
    stateofcdr.org
  17. Carbon Majors. Emissions traced to the largest fossil fuel and cement producers.
    carbonmajors.org
  18. IMO — Fourth Greenhouse Gas Study. International shipping emissions.
    imo.org — Fourth IMO GHG Study
  19. FAOSTAT — Emissions Totals. Agriculture, forestry and land use data.
    fao.org/faostat/en/#data/GT
  20. Project Drawdown — Table of Solutions. Comparative solution modelling and ranking.
    drawdown.org/solutions/table-of-solutions
  21. NASA — Vital Signs: Carbon Dioxide. Long-run concentration record.
    climate.nasa.gov/vital-signs/carbon-dioxide/
  22. Science Based Targets initiative. Corporate target-setting methods and scope 3 requirements.
    sciencebasedtargets.org

Reporting years differ by source (2016 for the sector split, 2023–2024 for totals). Percentages are rounded. Nothing here is a forecast; it is a snapshot with its edges shown.