The Angry Sky
A. Kam Napier
(page 3 of 7)
More cataracts. The UN report also notes that every 1 percent thinning of the ozone layer can result in 0.6 percent to 0.8 percent increase in cataracts, which are already the leading cause of blindness in the United States. UV exposure has also been linked to age-related nearsightedness.
Studies show that exposure to UV-B radiation can weaken the immune system in humans. Experiments in animals show that UV exposure weakens their immune response to skin cancer as well as infectious diseases. While skin cancer from UV generally threatens light-skinned people more, UV affects the immune systems of all races equally.
Ultraviolet radiation affects more than our health. Chances are, it’s burning a small hole in your wallet. Look in your closet for the quickest example—shirts that are dark and vibrant at the tails, where they are tucked in, but faded and thin across the shoulders. Ultraviolet radiation reacts with all materials that see the light of day, and as UV levels have increased, the wear and tear on materials has, too.
No one has even begun to calculate the economic cost of replacing materials worn out by UV exposure, or the added cost of having to replace them faster because UV levels have increased. But consider this list of materials affected by ultraviolet radiation from a 1994 UN assessment:
Pipes, water storage tanks, window and door frames, siding, gutters, roofing, wood used in buildings; outdoor furniture, such as stadium seats, park benches, beach furniture and artificial turf; natural and synthetic textiles and fibers (including your shirts); plastics and other composite materials used in cars, planes and boats; car tires; paint on outdoor surfaces including houses, buildings, cars and artwork; highway pavement markings; road signs; and more.
The UN report also describes how high temperatures and UV combine to further speed the breakdown of materials, noting that for areas near the equator, “even a very small increase in UV-B levels can translate into significant increases in the rate of degradation.”
Of course, the effects of UV radiation are not confined to humans and their belongings. We know that UV-B increases can damage crops. Rice plants, for instance, produce fewer and smaller grains of rice as a result of UV exposure. This may not have so direct an effect on Hawaii, where agriculture is waning, but native plant species may become even more vulnerable.
“Several native plants are affected by UV,” says Teramura. “Even small effects on long-lived plants, which may show no change from year to year, could build up. Then it’s possible that a more resistant plant species could take its place.”
You think sashimi is expensive now? UV also affects marine life, including the tiny plant organisms called phytoplankton, which are the basis for the entire ocean food chain. Also, many species of fish and crustaceans spend their formative years as larvae, floating on the surface of the ocean—and soaking up the rays. Increasing levels of UV make it harder for these larvae to survive. “Reduce the amount of floating plant and animal material in the ocean and it hits everything down the line,” says Teramura. “Eventually, it could affect commercial fishing.”
Contrary to popular belief, ozone depletion does not cause global warming. It’s easy to get the two concepts confused, since they are often mentioned in the same breath. But they are not interchangeable. Many people are under the impression that all the extra UV coming in through a weakened ozone layer is what raises the temperature of the Earth. Not so. Ultraviolet rays are radiation, but they are not heat.
However, the gases that cause ozone depletion—chemicals like CFCs, halons (used in fire extinguishers), methane and nitrogen—do double-duty as greenhouse gases. Even ozone-safe substitutes for CFCs are greenhouse gases. And as greenhouse gases, these substances do contribute to global warming, independent of their effect on the ozone layer. Which brings us to our friend—
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