International Environmental Agreements

Why we need international agreements

Some environmental problems are transboundary: the pollution, or the animals, cross borders. Others are global commons problems: the atmosphere, the oceans and the ozone layer belong to nobody, so every country is tempted to use them freely (the tragedy of the commons).

A single country that cuts emissions pays the cost, but shares the benefit with everyone. A treaty fixes this by making many countries act together.

The Montreal Protocol: protecting the ozone layer

The Montreal Protocol (1987) phases out ozone-depleting substances, mainly chlorofluorocarbons (CFCs). CFCs were used in refrigerators, air conditioners and aerosol spray cans.

How CFCs do damage:

1. CFCs are very stable, so they drift up to the stratosphere.

2. There, UV radiation breaks them apart and releases chlorine atoms.

3. One chlorine atom destroys thousands of ozone ($\text{O}_3$) molecules.

4. A thinner ozone layer lets more UV-B reach Earth's surface. That means more skin cancer and cataracts in people, and damage to crops and plankton.

To remember the chain: CFC → UV → Cl → less $\text{O}_3$ → more UV-B.

Why did Montreal succeed?

• Substitutes were available. Industry could switch to other chemicals (HCFCs, then HFCs and other alternatives).

• Clear schedules. Each chemical had a deadline, with extra time for developing countries.

• Trade restrictions. The Protocol bans trade in controlled substances with countries that did not sign, which gave countries a strong reason to join. A fund also helped poorer countries make the switch.

• Nearly every country signed, and the ozone layer is slowly recovering.

CITES: regulating wildlife trade

CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora, 1973) regulates international trade in wild animals, plants and products made from them. It does not protect habitat directly. It controls the buying and selling.

Species are placed on lists called Appendices:

How does a ban help? If there is no legal market, demand and prices fall, and fewer animals are hunted for profit. It also lets customs officers seize products.

Why is enforcement hard?

• Poaching happens in remote areas with few rangers.

• Illegal products are smuggled and sold on a black market.

• High prices for items like ivory or rhino horn make the risk worth it to criminals.

• Poorer countries may lack money and trained staff, and some officials can be bribed.

In the U.S., the Endangered Species Act helps enforce CITES inside the country.

The Kyoto Protocol

The Kyoto Protocol (1997) was the first major treaty to limit greenhouse gas (GHG) emissions. The largest contributor to climate change is carbon dioxide ($\text{CO}_2$), mostly from burning fossil fuels.

Key features:

• Binding targets for developed countries (for example, cutting emissions about 5% below 1990 levels on average).

• No targets for developing countries.

• Tools such as emissions trading.

The reasoning: developed countries industrialized first and have released most of the $\text{CO}_2$ now in the atmosphere. Developing countries still needed to grow their economies and reduce poverty. This idea is called "common but differentiated responsibilities."

The criticism: Emissions from large developing countries, such as China and India, were growing fast. Critics said the treaty would not stop global emissions and that it put developed economies at a disadvantage. The United States signed but never ratified it, and Canada later withdrew.

The Paris Climate Accord

The Paris Climate Accord (2015) aims to hold global warming well below 2 °C above preindustrial levels and to pursue efforts to limit it to 1.5 °C, mainly by cutting $\text{CO}_2$ and other GHGs.

Its design is different from Kyoto:

• All countries take part.

• Each country submits its own pledge, a nationally determined contribution (NDC).

• The targets in the pledges are not legally enforceable, though reporting is required. Countries report progress and update goals every five years ("ratchet up").

• Richer countries help fund poorer ones.

Advantage of self-set goals: countries join more easily because they choose what is realistic, so participation is high.

Weakness: with no penalty, pledges can be too weak or ignored. Even if every pledge were met, the total might not be enough to reach 1.5 °C.

Comparing treaties and judging success

Design trade-offs:

• A strong, binding treaty can cut emissions quickly among its members, but countries may refuse to sign or may withdraw.

• A flexible treaty keeps many countries involved, but cuts may be slow and uneven.

Why Montreal is hard to repeat for climate: CFCs had substitutes and a small set of producers. Greenhouse gases come mostly from fossil fuels, which power transportation, electricity and industry in every economy. Replacing them costs far more, touches every country and has no single "drop-in" substitute.

Back to the start: CFCs from one country harm the ozone layer everywhere, so countries had to act together. Montreal did it with substitutes and schedules. Climate treaties face a harder job because fossil fuels run the world economy.

Summary