How do carbon markets work and are they effective?

The short answer

A carbon market puts a price on emissions through a cap. Regulators decide how many allowances to auction or distribute, the cap declines over time, and emitters must hold one allowance per tonne of CO2 emitted. The price emerges from market trading and represents the marginal cost of compliance.

The EU ETS, launched in 2005 and now in its fourth phase, covers about 40% of EU greenhouse gas emissions from power, heavy industry, intra-EU aviation, and (since 2024) maritime transport. Its cap has been tightened to deliver a 62% reduction by 2030 versus 2005 levels. Average prices ran around EUR 65/tCO2 in 2024 after peaking at over EUR 100 in February 2023.

The mechanism is real, but its uneven traction across sectors limits how much it explains the broader transition.

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What the data shows

The EU ETS provides 20 years of price discovery data, with parallel evidence from the UK ETS, RGGI (US northeast), and California’s program. According to EEA, ESMA, and European Commission analyses:

• EU ETS average prices: EUR 5/tCO2 in 2017, EUR 25 in 2020, EUR 80-83 in 2022-2023, EUR 65 in 2024
• EU ETS revenue 2024: EUR 38.8 Bn (vs ~EUR 5 Bn in 2017)
• EU ETS coverage: ~40% of EU GHG emissions, expanded to maritime in 2024
• Cap reduction trajectory: -62% by 2030 vs 2005 levels
• Free allocation 2024: still nearly half of stationary installation emissions (free)
• Cumulative ETS revenue since launch: EUR 245 Bn by mid-2025
• EU CO2 emissions: -28% between 2010 and 2024 (vs -10% 1990-2010)

The exception that nuances the picture: the UK ETS averaged ~$57/tCO2 in 2024 vs EU’s ~$70 equivalent, while the US RGGI averaged barely $20. Carbon prices vary by an order of magnitude across jurisdictions, even among committed-to-net-zero economies. There is no global price.

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Why it happens — the macro mechanism

Carbon market effectiveness operates through three transmission channels with very different efficiency.

Channel 1 — Power sector substitution. Carbon prices change the relative cost of coal-fired vs gas-fired vs renewable generation. When EUA prices crossed EUR 50/tCO2 in 2021-2022, coal-to-gas switching accelerated significantly across European power markets. This is the channel where carbon pricing demonstrably works: alternatives exist, capital is fungible, and dispatch decisions respond to marginal cost. EU power-sector emissions fell roughly 30% between 2018 and 2024.

Channel 2 — Heavy industry and free allocation. Carbon prices have far less impact on cement, steel, chemicals, and aluminum because (a) substitution is technologically harder and (b) industries receive substantial free allocation to prevent “carbon leakage” to non-EU producers. Free allocation still covers nearly half of stationary installation emissions in 2024 (European Commission). The Carbon Border Adjustment Mechanism (CBAM), gradually replacing free allocation from 2026, aims to close this loophole by pricing carbon on imports — but the transition is gradual and the design is contested. This is the most underappreciated dimension of carbon market design: the headline price affects only the share of emissions actually exposed to market discipline.

A short note on cross-jurisdictional fragmentation. With EU ETS at EUR 65, UK ETS at $57, RGGI at $20, and most emerging markets at zero or near-zero, global carbon arbitrage remains structural rather than residual.

Channel 3 — Investment signal vs spot price. Long-duration capex decisions (steel furnaces, cement kilns, refineries) require expected future carbon prices, not current spot. The EU’s 2030 cap commitment provides a signal, but uncertainty about cap revisions, free allocation phase-out, and CBAM implementation creates basis risk. Project finance reflects this through hurdle rates and stranded-asset adjustments.

Synthesis by regime: in the 2008-2017 surplus regime with EUA prices below EUR 10, the market provided no meaningful price signal and emissions tracked the cap by accident more than by design; in 2018-2021, the introduction of the Market Stability Reserve absorbed the surplus and prices climbed above EUR 50, restoring credibility; in the 2022-2024 energy-crisis era, prices oscillated between EUR 60 and EUR 100 with high volatility, reflecting the system’s sensitivity to gas prices, industrial activity, and policy expectations.

A carbon market is only as effective as the share of emissions it actually exposes to its price.

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What it means for different economic actors

Savers. ETS revenues fund national budgets (~EUR 24.4 Bn to EU member states in 2024) and EU-level decarbonization programs. Some Member States use part of the revenue to support household electricity bills, particularly during the 2022-23 energy crisis.

Investors. Compliance carbon markets generate a derivatives complex (futures, options) used by emitters for compliance and by financial institutions for trading. ESMA documented EUR 648 billion of EUA-denominated trading on EU venues in 2023. Carbon derivatives have become a tradeable asset class with its own volatility regime, correlated with gas prices and industrial activity. Once a policy instrument trades like an asset, it is measured like one, which is how the measured cost of pursuing a second objective alongside return becomes visible at all.

Industrial firms. Carbon costs are now a meaningful margin determinant for power-intensive sectors. Steel produced via blast furnace generates roughly 1.8 tonnes of CO2 per tonne of steel — at EUR 65/tCO2, that is approximately EUR 117/tonne of carbon cost, against a steel price typically in the EUR 600-800/tonne range. Free allocation has historically absorbed most of this, but the CBAM phase-in changes the calculus.

A common error is to treat carbon prices as a uniform tax. They are sectorally asymmetric, jurisdictionally fragmented, and partially offset by free allocation. The headline price is the ceiling of effectiveness, not the average.

Practical observation

Go deeper

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Frequently asked questions

Why do carbon prices differ so much across jurisdictions?

Each carbon market is designed independently, with different caps, sectoral coverage, free allocation rules, and political tolerance for price levels. The EU ETS targets ~40% of EU emissions with a -62% by 2030 cap; the US RGGI covers only the power sector in northeast states with a much looser cap. Without a global price, carbon-intensive production migrates toward jurisdictions with lower or no carbon costs — the “carbon leakage” risk that CBAM aims to address. Coordinating prices globally would require something like an international carbon-price floor, which has been proposed but not adopted.

How does the Carbon Border Adjustment Mechanism (CBAM) work?

The CBAM phases out free allocation for sectors covered (electricity, iron and steel, aluminum, cement, fertilizers, hydrogen) and replaces it with a charge on imports equivalent to the EU carbon price. Definitive implementation begins in 2026, with full phase-in by 2034. The economic logic is to neutralize the competitiveness disadvantage of EU producers paying carbon costs while non-EU competitors do not. The administrative cost and compliance burden have generated significant pushback from emerging-market exporters, and the WTO-compatibility of the design remains contested.

Is carbon pricing the most efficient way to reduce emissions?

Economic theory generally favors a uniform carbon price as the most cost-effective way to reduce emissions for a given target, because it lets the lowest-cost reductions happen first. In practice, political constraints (sectoral protection, distributional concerns, fragmented coverage) mean carbon pricing rarely achieves theoretical efficiency. Most decarbonization observed since 2010 has come from a combination of pricing, regulation (renewable portfolio standards, vehicle efficiency mandates), and direct investment subsidies (IRA in the US, RePowerEU in the EU). The economic literature is divided on whether pure pricing or hybrid approaches deliver more reductions per dollar spent.

Last updated — 23 July 2026