TL: UNEP Ozone Depletion Report 94, GP Summary SO: Greenpeace International DT: March 14, 1995 Keywords: un reports greenpeace summary gp ozone atmosphere unep / Greenpeace summary of United Nations Environment Programme report: Environmental Effects of Ozone Depletion, 1994 Assessment (November 1994). Ozone depletion - the effects The effect at the Earth's surface of a loss of ozone is an increase in a type of light called UV-B radiation. It is this UV- B radiation that does damage to people, animals and plants. Increases in UV-B radiation caused by changes in ozone levels are expected in most places and have already been seen not only under the Antarctic ozone hole but also in the Alps and Canada. What will be the effect of increases in UV-B radiation? 1. Effects on human health 1.1 Skin cancer Skin cancer is already believed to have risen because of ozone depletion. The most common forms of skin cancer are types known as non-melanoma skin cancer. This skin cancer is caused by lifetime exposure to UV-B radiation. There has already been an increase in the dose of UV-B to people which would cause these cancers. It is estimated that between 1979 and 1993 the expected increase of this type of UV-B dose has been 8.9% at 55xN (the approximate latitude of Copenhagen and Moscow), 11.1% at 45xN (the approximate latitude of Venice and Montreal) and 9.8% at 35xN (the approximate latitude of Cyprus, Tokyo and Memphis). An average increase in UV-B dose of about 10% between 55xN and 35xN. Even bigger increases are believed to have occurred in the Southern hemisphere. United Nations Environment Programme (UNEP) forecast that for a 10% ozone depletion sustained over several decade this would amount to 250,000 additional cases per year. Even under the most recent international agreements on the phase-out of ozone depleting substances, a "plausible" model indicates that levels of this type of skin cancer will rise steadily and be 25% higher than 1980 levels in 2050 at 50xN (the latitude of Prague, Frankfurt and Vancouver). The more lethal melanoma cancers, which have a relatively high rate of death when they occur, may also increase in frequency. 1.2 The Immune system The ability of people to fight off infections is dependent on a strong immune system. Exposure to UV-B is now known to lower the effectiveness of the immune system, not just to skin infections but also to infections occurring throughout the body, including the gut and other organs. Effects on the immune system are highlighted by UNEP as one of the most worrying areas of uncertainty. They suggest that UV-B exposure might adversely influence immunity to infectious diseases. Examples of such diseases would be leishmaniasis, malaria, trichinosis, Lyme disease and possibly fungal infections like candida. The mechanism of immuno-suppression is thought to be independent of skin colour. Exposure to UV-B may well make the immune system tolerate rather than fight off an infection. This could mean that the effectiveness of vaccination programmes in both developed and developing countries are compromised. There is mounting evidence that UV-B has the ability to activate latent viruses such as papillomaviruses, herpes, and perhaps HIV. There is further evidence that sunscreens are not effective in preventing suppression of the immune system on exposure to UV-B radiation. 2. Natural Ecosystems Whilst people may be able to stay under cover and sunbathe less, many plants and animals cannot. Some effects on the natural world have already been seen. 2.1 Aquatic ecosystems Loss of plankton, the basis of all food in the seas, has been observed to be caused by extra UV-B from ozone depletion. Under the Antarctic ozone hole productivity from phytoplankton was down by 6-12%. UNEP predict that 16% ozone depletion [1] could result in 5% loss in phytoplankton, which would lead to a loss of about 7 million tons of fish per year - about 7% of fishery yield. 30% of the world's animal protein for human consumption comes from the sea; a greater proportion in developing countries. UV-B radiation also damages the developmental stages of fish (most notably anchovy, where near 100% mortality could occur for 16% ozone depletion), shrimps, crabs, amphibians and other animals. The most severe effects are in the ability of the creatures to reproduce. 3. Terrestrial ecosystems 3.1 Animals For animals, UV-B is implicated in the formation of skin cancer for several animals that have been studied, such as cows, goats, sheep and also cats, dogs and laboratory animals. This suggests that it is probably a quite general feature of UV-B exposure in animals. Bovine infections can be aggravated by UV-B. 3.2 Plants In many plants, UV-B radiation can have detrimental effects; it can alter plant form, damage tree growth, reduce plant growth, change the time of flowering, make plants more vulnerable to disease and cause them to produce toxic substances. There may well be losses of biodiversity and plant species, but our ignorance of the effects of UV-B on ecosystems as a whole is far too great to allow figures to be put on these losses. However, crops known to have cultivars vulnerable to UV-B increases include rice and soybean. 4. Air pollution With loss of ozone in the upper atmosphere, it is expected that UV-B radiation will cause ground-level ozone to increase in urban and suburban areas, reaching potentially harmful concentrations earlier in the day, and leading to levels which exceed air pollution standards more frequently. Low-level ozone is known to cause respiratory problems and aggravate asthma, as well as damaging crops and trees. Ozone depletion may further lead to more widespread problems with acid rain. [1] Although global ozone depletion has not reached that level, seasonal depletions of much more than 16% have been recorded over Antarctica and over much of the Northern hemisphere.