Changes to our ozone layer over the past 40 years have affected levels of UV radiation and therefore the risk of people developing skin cancer, an international study has found. Some 2,000 Australians die of skin cancer every year, with Australia having one of the highest rates of the disease in the world.
The study examined changes to the ozone layer and the impact on UV radiation, and changes in climate. One of the lead authors, Professor Robyn Lucas from The Australian National University, said the study highlights the harm associated with increased exposure to high levels of UV radiation. "It puts people at greater risk of developing skin cancers and other diseases," Professor Lucas said.
"Increased rates of skin cancer over the past 100 years show how susceptible some human populations would be to uncontrolled ozone depletion."
"For example, we know exposure to UV radiation accounts for up to 95 per cent of the risk of developing certain types of melanoma in light-skinned populations.
While melanoma accounts for less than five per cent of cancers, it has a particularly high mortality rate, with around 60,000 deaths worldwide each year. The study shows these numbers would have been much worse, if the Montreal Protocol hadn't been implemented by the UN in 2008.
The Montreal Protocol treaty led to the phasing out of the use of man-made substances that deplete the ozone layer, primarily chlorofluorocarbons (CFCs) that were used in refrigeration and as the propellant in aerosols.
"Without the Montreal Protocol, UV radiation levels in the near future would be more than twice what the World Health Organization considers extreme in many parts of the world, and close to four times the extreme level in the tropics," Professor Lucas said.
"These levels of UV radiation would have changed the whole way we live our lives - even a few minutes outdoors would have caused sunburn."
Professor Lucas believes more work still needs to be done to address big "gaps in our knowledge" when it comes to understanding how climate change will affect ozone and the effects of changing UV radiation on human health.
"We need a better understanding of how not only humans, but other species, respond to UV radiation," Professor Lucas said.
"The focus of concern regarding UV radiation has historically been on human health. We need long-term, large-scale studies to better understand how changes in UV radiation, together with other climate-change factors, also affect ecosystems on land as well as in the water.
"The outcomes of the Montreal Protocol show that globally united and successful action on complex environmental issues is possible."
The research was conducted by members of the United Nations Environment Programme's Environmental Effects Assessment Panel.
The paper has been published online in Nature Sustainability.