In April, scientists in the United States found that the depletion of ozone gas in the world’s atmosphere was at least three times more serious than had been predicted. This means that more ultraviolet rays are reaching the earth past a thinning “ozone shield”, increasing cancer rates and harming human vision and crop productivity. For us in the Himalaya, the immediate question is what impact the decline in atmospheric ozone will have on high mountain regions, particularly on the health of people, livestock, crops and forests. Will the hills be more affected than the plains? Himal’s Prakash Khanal found scientists agreed on the answer: yes. His report:
Trekkers on the mountain trails have known it for long. Up in the rarified atmosphere of the High Himalaya, the skin peels quicker and sunburn is instant because ultraviolet rays pierce through the thin atmosphere easily. Significant ozone depletion would mean that the higher altitudes would be much more affected by ultraviolet rays, which are sufficiently strong to break even biological molecules like the DNA, which controls heredity and cell control.
It is only in the past four years that the depletion of ozone began to be taken seriously, and studies so far have concentrated on confirming the general worldwide depletion and studying an “ozone hole” over Antartica. However, from what is known, there seems to be cause for concern in the Himalayan region because of the general thinning of the ozone shield worldwide and the strong possibility that a ozone hole similar to that over the South Pole hovers over the Himalaya.
“Naturally, increasing levels of ultraviolet radiation will affect the mountain people and crop production, the more so at higher altitudes,” Sekhar Gurung, Associate Professor of Physics at Tribhuvan University. “If it is true that atmospheric ozone is being depleted, then, without doubt, the mountain environment is being affected. But more research needs to be done to determine the extent,” says Suresh Chalisey, a meteorologist presently with the International Center for Integrated Mountain Development (ICIMOD).
Scientists have theorized that ozone holes probably exist over the Arctic and Greenland, and Himal has learnt that a meteorological station in Switzerland has detected significant depletion of the gasover the Alps. If an ozone hole exists over the South Pole, and possibly over the Alps and Greenland, could there also be a similar “hole” over the Himalaya?
According to Dan Dudek of the Environmental Defense Fund in New York, ozone holes could be due to “polar stratospheric clouds” found in extremely cold regions. These clouds contain aerosol-type ice crystals that react easily with manmade chlorofluorocarbons (CFCs) in the atmosphere. The reaction between the ice crystals and CFCs uses the ozone gas in the immediate area, creating a “hole”. Dudek says it is entirely possible that these conditions, known to exist over the South Pole, could also be present over the mountains of South-Central Asia.
But even without a “hole” over the Himalaya, the worldwide depletion of ozone is already reason enough to start worrying in relation to high mountain populations. As you go higher, there is less atmosphere above. In rural areas, as in the Himalaya, there is also less smog which acts as a an additional screen. As more ultra-violet rays reach the surface of the earth, in the Himalaya or elsewhere, there will be increases in cancer rates, cataract and other eye diseases, according to Dr. Margaret Kripke, an immunologist with the Environmental Protection Agency (EPA), which is the primary United States agency conducting research on ozone. There is also a possibility that increased exposure will negatively affect the body’s immune system, which in turn might increase susceptibility to infectious disease.
No one has done region-specific calculations, but the EPA’s computer models give some indication of the numbers involved. If the actions required by the 1987 Montreal CFC-control treaty were observed, the EPA says, they would avert 132 million cases of skin cancer and 27 million deaths from skin cancer that would otherwise have occured among people born before 2075. Even with the new controls, Canada’s Environment Ministry estimates that there will be 7 million extra skin cancer cases among people born between now and 2075. Logic suggests that a disproportionate number of those skin cancer victims are going to come from higher climes. Moreover, these calculations were done before the April findings that ozone depletion was three times greater than previously thought.
Increased ultraviolet radiation would also affect crop production, animal life and the growth of trees. Studies have shown that two- thirds of all plant life are affected by ultraviolet radiation. Martyn Caldwell of the National Science Foundation in Washington DC, who has studied plants in arctic and alpine zones, cautions that enough specific analysis has not been carried out on the subject to make any dire predictions. However, he says, it is quite possible that ozone depletion could result in direct damage to certain plants in high altitudes and it is possible that mountain crop production and quality will go down.
The next phase of scientific investigation, agree Dudek, Kripke and Caldwell, should be an in-depth worldwide examination of the ozone problem. Going beyond the study of global averages, the next phase of research must relate to specific regions by latitudes and altitudes. Nepali scientists could not agree more. The Himalaya offer one of the best natural laboratories for research into the atmospheric sciences, and the question of ozone provides an urgency for serious research, says ICIMOD’s Chalisey.