A carbon tax is grounded in the concept of the social cost of carbon. This is an estimate of the economic damage caused by emitting one tonne of CO₂, including climate-related health, infrastructure and ecosystem impacts.
A carbon tax is typically levied per tonne of CO₂ emitted. The tax can be applied either upstream (on fossil fuel producers) or downstream (on consumers or power generators). This makes carbon-intensive activities more expensive, it incentivises nations, businesses and people to reduce their emissions, while untaxed renewable energy becomes more competitively priced and appealing.
Carbon tax was first introduced by Finland in 1990. Since then, more than 39 jurisdictions have implemented similar schemes. According to the World Bank, carbon pricing mechanisms (that’s both carbon taxes and emissions trading systems) now cover about 24% of global emissions. The remaining 76% are not priced, mainly due to limited coverage in both sectors and geographical areas, plus persistent fossil fuel subsidies. Expanding coverage would require extending carbon pricing to sectors like agriculture and transport, phasing out fossil fuel subsidies and strengthening international governance.
What is carbon tax?
Sweden has one of the world’s highest carbon tax rates and has cut emissions by 33% since 1990 while maintaining economic growth. The policy worked because Sweden started early, applied the tax across many industries and maintained clear, consistent communication that kept the public on board.
Canada introduced a national carbon tax in 2019. In Canada, most of the revenue from carbon taxes is returned directly to households through annual rebates, making the scheme revenue-neutral for most families. However, despite its economic logic, inflation and rising fuel prices led to public discontent – especially as many citizens were unaware they were receiving rebates.
Carbon taxes face challenges including political resistance, fairness concerns and low public awareness. Their success depends on clear communication and visible reinvestment of revenues into climate or social goals. A 2025 study that surveyed 40,000 people in 20 countries found that support for carbon taxes increases significantly when revenues are used for environmental infrastructure, rather than returned through tax rebates.
By Meilan Yan, associate professor and senior lecturer in financial economics, Loughborough University
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