Mitigation: national action and global agreements

National mitigation

• Renewable energy: wind, solar, hydro and geothermal replace fossil fuels.
• Carbon taxes and emissions trading: put a price on carbon so polluters pay and cleaner options become cheaper.
• Recycling and efficiency: less energy used in making goods, insulating homes, efficient transport.
• Carbon sinks: afforestation and protecting forests.

Progress is uneven: action depends on wealth, energy resources (coal-rich countries face high costs of change), politics and public attitudes.

Montreal Protocol (1987)

Signed in September 1987 to phase out ozone-depleting substances such as CFCs. Nearly 99% of banned substances have been eliminated; the ozone layer should return to 1980 levels by about 2040, by 2045 over the Arctic and about 2066 over the Antarctic (UN, 2023). It has also helped avoid an estimated 0.5 C of warming, because many of the gases are also greenhouse gases.

It succeeded because the problem was clear, few industries were involved, and substitutes were available.

Kyoto Protocol (1997)

Adopted 11 December 1997, in force 16 February 2005. It set binding targets for 37 industrialised countries and economies in transition plus the EU: an average 5% cut below 1990 levels in 2008 to 2012. The Doha Amendment set a second period (2013 to 2020) with a cut of at least 18% below 1990 levels. It bound only developed countries, under the principle of common but differentiated responsibilities (UNFCCC), so fast-growing emerging economies had no binding targets.

Paris Agreement (2015)

Agreed at COP21 on 12 December 2015, in force 4 November 2016. Aim: keep warming well below 2 C above pre-industrial levels and pursue efforts to limit it to 1.5 C. Every party submits nationally determined contributions (NDCs) every 5 years, each more ambitious than the last; a global stocktake took place in 2023 and every 5 years after (UNFCCC).

Strength: almost universal. Weakness: NDCs are set nationally and not legally binding in size, and IPCC analysis shows deep cuts (about 43% by 2030) are needed for 1.5 C.

Worked example

Explain why the Montreal Protocol was more successful than climate agreements on CO2.

1. Ozone-depleting gases came from a small number of products and industries.
2. Affordable substitutes were available, so the cost of change was low.
3. CO2 comes from almost all energy use, so cutting it affects whole economies and involves every country.

Answer: A narrow, cheap-to-solve problem compared with CO2, which is built into the global energy system.

Check yourself

1. Practice question: Kyoto targets averaged a 5% cut below 1990 levels. If a country with 1990 emissions of 800 Mt had a 5% target, what would its target be?
   Show answer

   760 Mt. 800 x 0.95 = 760 Mt.

2. Practice question: under the Doha Amendment parties committed to cuts of at least 18% below 1990. For a country with 1990 emissions of 800 Mt and an 18% cut, what is the maximum allowed?
   Show answer

   656 Mt. 800 x 0.82 = 656 Mt.

3. Which feature of the Kyoto Protocol limited its effect on global emissions?
   • It banned all fossil fuels
   • It had no targets at all
   • Binding targets applied only to developed countries
   • It only covered ozone
   Show answer

   Binding targets applied only to developed countries. Emerging economies, whose emissions grew rapidly, had no binding targets.

4. Under the Paris Agreement, countries must
   • accept the same emissions target
   • submit nationally determined contributions every 5 years
   • cut emissions to zero by 2020
   • pay a global carbon tax
   Show answer

   submit nationally determined contributions every 5 years. NDCs are national pledges, updated every 5 years with rising ambition.

5. How does a carbon tax reduce emissions?
   • It bans cars
   • It plants trees directly
   • It lowers the price of coal
   • It makes fossil-fuel use more expensive, so firms and people switch to cleaner options
   Show answer

   It makes fossil-fuel use more expensive, so firms and people switch to cleaner options. Pricing carbon changes behaviour.

6. According to the UN, how much warming has the Montreal Protocol helped avoid?
   • About 5 C
   • About 0.5 C
   • None
   • About 0.05 C
   Show answer

   About 0.5 C. Many ozone-depleting substances are also powerful greenhouse gases.

7. Explain why national mitigation has happened in some countries but not others.
   Show answer

   It is expensive, so poorer countries and those that depend on coal or oil find change costly, while wealthier countries can afford renewables; politics and attitudes also differ.. Cost and dependence on fossil fuels vary; so do politics.

Practise with instant feedback Print this lesson

Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Geography specification (Issue 3, September 2025)
• UN News: Ozone layer recovery is on track (9 January 2023)
• UNFCCC: What is the Kyoto Protocol?
• UNFCCC: Key aspects of the Paris Agreement
• IPCC AR6 Synthesis Report: Summary for Policymakers (2023)

Last updated 8 November 2026. Spotted a mistake? Tell us.