Ozone Lessons for Addressing Climate Change

September 13, 2022

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Reflecting on the International Day for the Preservation of the Ozone Layer offers a hopeful lesson for climate change.

Three distinct evolutions have shaped life on Earth. The first evolution was the emergence of single celled life at least 3.8 billion years ago. The second evolution, a billion or so years later, began with the evolution of a unique life form — blue green algae.

Blue green algae began to convert solar energy to chemical potential energy stored as carbohydrate in the organism. This photosynthetic process releases oxygen as a novel waste product. Through the production of oxygen, blue green algae fundamentally changed the composition of the Earth’s atmosphere.

As oxygen levels rose, an ozone layer formed. Stratospheric ozone forms naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen producing a highly reactive gas composed of three oxygen atoms. The ozone layer stopped harmful radiation from the sun from reaching the surface of the planet. This set the stage for a third evolution and the emergence of complex life on the planet including humans.

In 1974, two American scientists put forward a theory that human activity was damaging the ozone layer. While their theory was initially met with skepticism, twenty years of subsequent scientific research proved them right.

In 1987, representatives from 24 countries met in Montreal and announced to the world that it was time to stop destroying the ozone layer. These countries made a commitment — through the Montreal Protocol on Substances that Deplete the Ozone Layer — to rid the world of substances that threaten the ozone layer. As a result of their actions, the ozone layer is projected to recover by the middle of the century but only if the recommendations in the Montreal Protocol continue to be implemented. Already, the Protocol is saving an estimated two million people each year by 2030 from skin cancer.

On December 19, 1994, the UN General Assembly proclaimed September 16 to be the International Day for the Preservation of the Ozone Layer, commemorating the date when the Montreal Protocol was signed in 1987.

The Montreal Protocol is a landmark international environmental agreement that is making a difference. As we better understand the carbon cycle and its role in establishing a climate that protects life on the planet, we can learn from the success of this agreement as we strive to reverse climate change.