Carbon markets
How carbon credits trade
One carbon credit equals one tonne of CO₂-equivalent avoided or removed. This page explains how those credits are created, priced and traded — and how three rulebooks covered in our Knowledge base (the US SEC climate rule, aviation's CORSIA, and India's Carbon Credit Trading Scheme) shape the market Kerala's dams could one day sell into.
1. What a credit is
A credit is a certificate issued by a registry (Verra, Gold Standard, or a government scheme) after an independent auditor verifies that a project avoided or removed one tonne of CO₂e against a baseline. For a reservoir, that could be methane captured before it bubbles out of the water, riparian reforestation in the catchment, or clean hydro generation that displaces coal power on the grid.
Credits only have value if they are additional (the reduction would not have happened anyway), permanent, and not double-counted — which is why registries, serial numbers and retirement records matter as much as the project itself.
2. Two markets, two price logics
- Compliance markets — governments cap total emissions and hand out or auction allowances (EU ETS, and now India's CCTS for energy-intensive industries). Prices are set by scarcity: tighten the cap and the price rises. The EU ETS has traded roughly €60–90 per tonne in recent years.
- Voluntary markets — companies buy credits to meet their own net-zero pledges. Prices vary wildly (under $1 to over $50 per tonne) based on project type, vintage, co-benefits and perceived quality. Nature-based credits with strong verification command a premium.
3. The three rulebooks
SEC (United States). The SEC climate rule requires large listed companies to disclose Scope 1 and 2 emissions with third-party attestation, plus climate-risk footnotes in financial statements. Once a footprint is audited and public, it becomes a liability investors can price — which is what turns carbon from a PR metric into a balance-sheet item and drives demand for credits and clean power contracts.
CORSIA (aviation). ICAO's scheme requires airlines on international routes to offset any growth above 85% of 2019 emissions with approved credits, or to cut emissions with sustainable aviation fuel. It created the first global, sector-wide compliance demand for credits — billions of tonnes of expected demand through 2035 — and set strict eligibility lists for which credits count.
CCTS (India). India's Carbon Credit Trading Scheme, run by the Bureau of Energy Efficiency, sets emissions-intensity targets for obligated sectors (power, cement, steel, pulp, petrochemicals…). Over-performers earn credits they can sell; under-performers must buy. A voluntary offset mechanism lets outside projects — including forestry and small hydro — issue credits into the same market. This is the door through which a Kerala dam's verified catchment or methane projects could eventually trade.
4. Why the price of carbon tends to rise
Compliance caps tighten every year by design, so allowances get scarcer. Disclosure rules (SEC, CSRD, India's BRSR) keep expanding the pool of companies that must report and act. And financing now rewards low footprints directly: sustainability-linked loans charge higher interest when a borrower misses emissions targets and less when it beats them — so a high carbon footprint literally costs more to carry. Airlines add a further demand floor through CORSIA. The result is a commodity whose long-run incentive structure points upward, which is why early, well-verified credits are treated as an appreciating asset.
5. What this means for Kerala's dams
Every reservoir page on JalaNet now carries an Environmental & Carbon Accounting panel: estimated methane emissions, the catchment's green-carbon sink, blue-carbon sediment burial, and the coal power each dam's generation displaces. Those figures are screening estimates — no Kerala dam publishes measured emissions yet — but they map exactly onto the categories a CCTS or voluntary-market project would need to verify: a baseline, a monitored reduction, and a registry.
Dams that are net carbon sinks (large forested catchments, older reservoirs past their methane peak) are the natural candidates for credit projects; net emitters show where mitigation — catchment reforestation, aeration, floating wetlands — would pay for itself.
Read the full guides
- SEC climate rules & carbon marketsDisclosure mandates, attestation and why reported footprints move prices.
- Aviation carbon & market historyCORSIA baselines, sustainable aviation fuel, and the road from Rio 1992 to Paris Article 6.
- The three types of carbon footprintScopes 1–3 and the green / blue / black carbon spectrum behind every credit.