A new research study shows the Montreal Protocol, an international agreement to protect the ozone layer, is expected to prevent 443 million cases of skin cancer and 63 million cataract cases for people born in the United States through the end of the century.
Researchers include scientists at the National Center for Atmospheric Research in Boulder, ICF Consulting and the U.S. Environmental Protection Agency.
NCAR scientist Julia Lee-Taylor said the study focuses on adverse health effects of the Montreal Protocol and its subsequent amendments, which aims to regulate and eliminate use of chlorofluorocarbons that destroy ozone in the stratosphere. The Montreal Protocol was signed in 1987 after scientists discovered a hole in the ozone layer over the Antarctic in 1985.
Lee-Taylor said the Montreal Protocol provided about half the benefit needed, and the subsequent amendments helped strengthen the treaty and virtually eliminate the problem by expanding the list of ozone-destroying substances.
The ozone layer absorbs ultraviolet radiation and protects living organisms on Earth.
“The adverse health effects come because ozone filters out UV in the atmosphere,” Lee-Taylor said. “If you reduce the ozone, you allow more UV to come down to the surface of the Earth, and that can have adverse health consequences, such as skin cancer and cataracts. So if you allow the ozone layer to heal, then you reduce the UV, and you reduce the number of adverse health consequences.”
The scientists created a five-part computer modeling approach that allowed them to predict what different outcomes would be for Americans born between 1890 and 2100. Lee-Taylor said the model includes data about chemical emissions, the amount of chlorine in the stratosphere, the amount of UV at ground level for a certain amount of ozone, health data and projections about the U.S. population from the U.S. Census Bureau.
David Hosansky, NCAR media relations manager, said the model enables scientists to simulate past and future emissions of ozone-destroying substances, the impacts of those emissions on ozone in the stratosphere, the resulting changes in levels of UV radiation that reaches Earth’s surface, the U.S. population’s exposure to the radiation and resulting health effects.
In addition to prevention of 443 million skin cancer cases and 63 million cataract cases, 2.3 million skin cancer deaths will be avoided in the U.S. due to the treaty and its amendments.
Hosansky said research is important for two reasons: quantifying the extent to which ozone layer recovery will benefit society, and demonstrating what happens when the international community works together to tackle environmental problems.
“It’s remarkable that the treaty’s phaseout of ozone-destroying substances like CFCs will prevent more than 99% of potential health impacts that would have otherwise occurred from ozone destruction,” Hosansky said in an email.
Lee-Taylor said as scientists learn more about the situation, policymakers can strengthen new regulations if appropriate to help serve the public better.
“I think it gives us some hope about the power of the international community to make environmental regulations that solve real problems and benefit people’s lives,” Lee-Taylor said.
The study can be viewed in ACS Earth and Space Chemistry at bit.ly/3uZW0nn.
