The shared economic problem
A decision can create climate-related costs beyond the producer’s private accounts. Carbon pricing makes covered emissions financially consequential. The way the price is created differs between a tax and an allowance market.
Two different starting points
A carbon tax directly specifies a charge per covered unit. An emissions trading system sets an allowance limit and lets covered participants trade. Hybrid designs and detailed rules can complicate the textbook distinction. Neither should be evaluated without its coverage and enforcement arrangements.
A simple reduction example
At an illustrative carbon price of £40 a tonne, reducing a taxable tonne for £25 saves £15 before other effects. Reducing a tonne for £60 is more costly than paying that charge in this simplified calculation. This is not a current policy rate or a full social appraisal.
Look beyond the mechanism
Revenue use, household impacts, competitiveness and monitoring affect policy outcomes. Distribution matters: a measure can change total incentives while affecting groups differently. Link marginal abatement cost with social cost before judging a policy solely by the headline price.