Carbon-trading schemes, also known as emissions trading schemes (ETS) or “cap and trade,” are market-based policy tools designed to reduce greenhouse gas (GHG) emissions.
They work by creating a financial incentive for companies to reduce their carbon footprint.
How They Work: The “Cap and Trade” Principle
- Setting the Cap: A government or regulatory body sets an overall limit, or “cap,” on the total amount of GHG emissions that can be emitted by all participating entities (e.g., power plants, industrial facilities) within a given sector or country. The cap is set to decrease over time, ensuring a steady reduction in emissions.
- Issuing Allowances: The regulator then issues a limited number of “allowances” or “permits,” with each allowance representing the right to emit one tonne of carbon dioxide equivalent (CO2e). These allowances are either allocated for free to companies or sold through an auction. The total number of allowances issued matches the cap.
- Trading: Companies must hold enough allowances to cover their emissions at the end of a compliance period.
- Companies that emit less than their allowance limit can sell their excess allowances to other companies.
- Companies that emit more than their limit must purchase additional allowances from the market.
This system creates a market for carbon emissions, where the price of an allowance is determined by supply and demand. Companies with low-cost options for reducing emissions will do so and sell their surplus allowances for a profit. Conversely, companies with high-cost reduction options may find it cheaper to buy allowances. This mechanism ensures that the overall emission reduction target is met at the lowest possible cost to the economy, as reductions are made where they are most cost-effective.
Types of Carbon Markets
There are two primary types of carbon markets:
- Compliance Markets: These are regulated by governments, which establish binding caps on emissions. They are mandatory for the companies and sectors they cover. The allowances traded in these markets are often referred to as “carbon credits” or “allowances.” The European Union Emissions Trading System (EU ETS) and California’s Cap-and-Trade Program are prominent examples of compliance markets.
- Voluntary Markets: In these markets, businesses, organizations, and individuals voluntarily purchase carbon credits to offset their emissions. These credits are generated by projects that reduce or remove GHG emissions (e.g., renewable energy projects, reforestation, or waste management). Unlike compliance markets, there is no government-mandated cap, and participation is optional. The demand for these credits is driven by corporate sustainability goals and a desire to achieve “net-zero” or “carbon-neutral” status.
Criticisms and Challenges
While carbon trading schemes are widely seen as a key tool for climate action, they also face criticism. These include:
- Price Volatility: The price of allowances can fluctuate, making it difficult for companies to plan long-term investments in low-carbon technologies.
- Carbon Leakage: There is a risk that companies in countries with a strict ETS might move their operations to countries with laxer regulations, leading to no net reduction in global emissions.
- Oversupply of Credits: If the cap is not set stringently enough or too many allowances are issued, the price of carbon can drop, reducing the incentive for emissions reduction.
- Effectiveness of Offsets: Critics of voluntary markets argue that the environmental integrity of some carbon offset projects can be questionable, and that they may not always represent real, additional emissions reductions.