The Montreal Protocol

Submitted by James Riordan with contributions from the Chemical Production Division

The ozone layer is the Earth’s atmospheric shield, which prevents Ultraviolet (UV) radiation from harming humans and other forms of life. In 1985, the discovery of a gaping hole in the ozone over the South Pole caused worldwide concern (Figure 1). Countries across the world then realized that they had to take action on the “ozone depleting substances” that were often used in refrigeration, air conditioning, foam blowing, aerosols, fire extinguishers and solvents.

Adopted on September 16, 1987, all 198 nation member states of the United Nations have now signed on to the Montreal Protocol. Originally designed to reduce some key substances that harm our ozone layer, the Protocol was modified over the next few years to incorporate the total phase-out of the production and consumption of over 100 ozone-depleting substances.

Parties to the Protocol have phased out 98% of ozone depleting substances globally compared to 1990 levels. Scientists monitoring the atmosphere say that this has halted the damage to the ozone layer, which should recover by the middle of this century. It is estimated that this saved 2 million people from getting skin cancer. Since many of these substances are also potent greenhouse gases, the agreement has also helped the world take a major step forward in the battle against climate change.

In 2016, Canada played a leading role in international efforts to adopt the Kigali Amendment to the Montreal Protocol, which requires a phase-down of hydrofluorocarbons (HFCs). As HFCs are powerful greenhouse gases used as substitutes for some ozone-depleting substances, the Kigali Amendment is expected to contribute to avoiding up to half a degree Celsius in global temperatures by 2100.

The United Nations recognizes the Montreal Protocol as one of the most successful treaty in their history. It continues to be an inspiring example of what is possible when we all come together to tackle global problems.

We invite you to read more about some of our notable past employees who helped contribute to The Montreal Protocol:

A composite satellite image of the ozone hole over Antarctica. Dark blue shading is shown to distinguish thinner areas of the ozone layer.

Figure 1: A composite image of the ozone hole in 2009, which develops over the South Pole each year. The size and depth is monitored to measure effects of reducing ozone depleting substances through efforts such as the Montreal Protocol. Photograph copyright of NASA

A shiny gold scientific instrument. There is a gold conical shape on top of a gold cube platform.
Figure 2: The Fourier Spectrometer: an instrument that can take atmospheric measurements. It is a part of the Atmospheric Chemistry Experiment mission onboard the SCISAT satellite, which launched in 2003. It uses sunlight to identify gases and particles in the Earth's middle atmosphere. The data help us better understand our ozone layer. © Canadian Space Agency
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