The Montreal Protocol: 25 Years After

SEPTEMBER is Ozone Protection Month. This Sunday, September 16, is special because it is the 25th anniversary of the Montreal Protocol, the agreement designed to protect the Earth’s ozone layer. It was signed initially by 24 countries in 1987 but has been ratified by 197 countries. It is the most successful treaty in terms of international participation. All countries in the United Nations signed the protocol.

As a proof of the success of the Montreal Protocol, the United Nations Environment Programme (UNEP) said the ozone layer has not grown thinner since 1998 over most of the world, and it appears to be recovering because of reduced emissions of ozone-depleting substances (ODS). The ozone layer is projected to return to pre-1980 levels by 2050 to 2075.

Montreal Protocol had together phased out 98 per cent of ozone depleting substances, reducing production levels from a 1987 level of over 1.8 million weighted tonnes annually to some 45,000 tonnes in 2010. If you have a late model car, your aircon is already loaded with R-134A refrigerant which is the replacement for the ozone-depleting R-12 Freon.

The Philippines being a signatory to the Montreal Protocol, created the Philippine Ozone Desk through the DENR Environmental Management Bureau (EMB). The office facilitates and coordinates Ozone Depleting Substances' phase-out projects and policies in the country.

Ozone Basics

Ozone is a gas that is naturally present in our atmosphere. Each ozone molecule contains three atoms of oxygen and is denoted chemically as O3. Ozone is found primarily in two regions of the atmosphere. About 10% of atmospheric ozone is in the troposphere, the region closest to Earth (from the surface to about 10-16 kilometers). The remaining ozone (90%) resides in the stratosphere, primarily between the top of the troposphere and about 50 kilometers altitude. The large amount of ozone in the stratosphere is often referred to as the “ozone layer” (Source: UNEP website).

The ozone layer forms a thin shield high up in the sky protecting life on Earth from the sun's ultraviolet (UV) rays. In the 1980s, scientists began finding clues that the ozone layer was going away or being depleted. This allows more UV radiation to reach the Earth's surface. This can cause people to have a greater chance of getting too much UV radiation. Too much UV can cause bad health effects like skin cancer and eye damage.

Scientists discovered that human-produced chemicals, specifically chlorofluorocarbons (CFCs) and Halons, when they break into the atmosphere release chlorine atoms and causes ozone depletion. CFCs were discovered in 1928 and were considered wonder gases because they are long-lived, non-toxic, non-corrosive and non-flammable. From the 1960’s they were increasingly used in refrigerators, air conditioners, spray cans, solvents, foams, and other applications. Halon 1301 is used primarily in fire extinguishers and has proven to be very effective fire suppressants (Source: US EPA).

To stop the destruction of the ozone layer, the gradual phase out of ODS was proposed. This resulted in the signing of the Montreal protocol.