Most people unfortunately know the ache of sunburn – worse, many people know the pain and loss of skin cancer – but do we really understand what’s behind it all?
While skin cancers are commonly linked with our long, hot summers – is it really temperature that gives the best indication of whether or not we could be burnt?
We spoke to the Bureau of Meteorology to get to the bottom of what ultraviolet radiation really is, how we need to change our sun safety habits, and why we’re so vulnerable in Australia.
How does UV radiation reach us?
Ultraviolet radiation, more commonly known as UV, is radiation generated from the sun and sent into our atmosphere.
While the earth’s ozone layer reflects most of it, and cloud cover can stop it finding the earth’s surface, a certain amount still reaches us.
It’s overexposure to this that can cause damage to skin cells and lead to skin cancer.
Vernon Carr, National Manager of Public and Agricultural Weather Services at the Bureau of Meteorology, says that risk of overexposure doesn’t stop when summer ends.
“UV radiation levels have no relationship to temperature,” Mr Carr says.
He explains that while summer is worse due to the position of the sun and clearer days, it isn’t how hot it is that makes the difference – autumn and winter can often pose dangers.
UV radiation at the surface is directly related to sun angle and ozone levels in the atmosphere.
Most regions in Australia in the middle of winter, including New South Wales, will still experience UV levels above three during the day.
“When the UVI climbs above three, sun protection measures are recommended.”
The UV index rates levels between one and 11+, with the higher number meaning a higher exposure to UV radiation.
Why is sun protection so important in Australia?
Skin cancer is often labelled Australia’s national cancer.
We have the highest rate of melanoma in the world, and approximately 13,000 new cases of skin cancer were diagnosed in 2015 alone. So what’s happening?
Contrary to factors such as temperature and ozone coverage, Mr Carr explains that Australians are predisposed to a significant risk of UV exposure due to the country’s location.
“Australia is in the higher latitudes compared with, for example, most European countries, and generally has a lot more cloud free days,” Mr Carr says.
“Therefore, much higher levels of UV radiation."
Breaking that down, he says that UV radiation is higher for countries closer to the equator because of the angle of the sun – the higher the sun in the sky, the higher levels of radiation to be expected.
Additionally, less cloud cover means more UV radiation is reaching the earth’s surface.
“In summer at midday, assuming the skies are clear, the whole of Australia could experience UVI levels greater than 11 – that’s extreme levels of UV according to the World Health Organisation scale of UV Index,” Mr Carr says.
More information about skin cancer protection