Do we need to worry about relatively small increases in UV-B due to ozone depletion, when natural variability is so much larger?
Yes. The change in UV-B from ozone depletion is systematically upward. The natural variability (e.g., from time of day, or clouds) can be larger, but goes in both directions, up and down. While the evidence for ozone depletion is very strong, there is little evidence for long-term changes in cloud cover. Many detrimental effects of UV-B are proportional to the cumulative UV-B exposure. For example, skin cancer results from the total exposure accumulated over many years under both sunny and cloudy conditions. Any systematic increase in UV-B radiation will increase incidence among a population (as well as individual risk) regardless of the natural variability of the UV-B radiation. • Does one get higher UV exposures at higher elevations? Yes. Higher elevations have less atmosphere overhead, as evidenced by the thinner air and lower atmospheric pressure. The increase in sun-burning UV radiation is typically about 5-10% for each kilometre of elevation, the exact number depending on the spe
Yes. The change in UV-B from ozone depletion is systematically upward. The natural variability (e.g., from time of day, or clouds) can be larger, but goes in both directions, up and down. While the evidence for ozone depletion is very strong, there is little evidence for long-term changes in cloud cover. Many detrimental effects of UV-B are proportional to the cumulative UV-B exposure. For example, skin cancer results from the total exposure accumulated over many years under both sunny and cloudy conditions. Any systematic increase in UV-B radiation will increase incidence among a population (as well as individual risk) regardless of the natural variability of the UV-B radiation.
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- Do we need to worry about relatively small increases in UV-B due to ozone depletion, when natural variability is so much larger?
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