Developed countries mainly adopt comprehensive economic and fiscal policies to reduce greenhouse gas emissions, including: voluntary agreements, energy/carbon dioxide taxes, emissions trading, renewable energy or cogeneration production quotas, energy efficiency standards, and renewable energy Direct funding incentives for energy, such as preferential rates, grants, tax exemptions, etc. However, these policies are constantly changing with the differences in implementation. Taking energy/CO₂ taxation as an example, it has changed from a pure taxation to a "tax + subsidy" form. In the early 1990s, some developed countries began to implement energy or CO₂ taxes based on the carbon content of fuels in order to increase fiscal revenue and/or reduce their dependence on foreign oil supplies.
