What is the current state of the ozone layer and what are the consequences of ozone depletion? Impact on human health. aquatic ecosystems. Terrestrial ecosystems. air pollution. Between 19 and 23 kilometers above the Earth’s surface, in the stratosphere, a thin gas shield, the ozone layer, surrounds the Earth and protects it from the sun’s dangerous rays. Ozone is created by the action of sunlight on oxygen and is the only substance in the atmosphere that can absorb harmful ultraviolet (UV-B) radiation from the sun. This thin shield makes life on earth possible.
Since 1974, scientists have been warning us of a possible global crisis resulting from the progressive depletion of the ozone layer by man-made chemicals such as chlorofluorocarbons (CFCs). It has taken too long for the world to understand these early warnings.
Today, the international community is just a mere spectator who has to watch as the ozone layer disappears, year after year, with reports of its depletion and the compromising rise in ultraviolet radiation and the cumulative damage to various living organisms.
What are the consequences of ozone depletion?
Ozone depletion on the earth’s surface leads to an increase in ultraviolet B radiation. This type of UV-B radiation is harmful to people, animals and plants. An increase in UV-B radiation has not only been observed under the Antarctic ozone hole, but also in other places such as the Alps (Europe) and Canada (North America).
1. Effects of the ozone hole on human health.
1.1 Skin Cancer.
Nowadays it is estimated that the rate of skin cancer has increased due to the depletion of stratospheric ozone. The most common type of skin cancer, called non-melanoma, is caused by years of exposure to UVB radiation. There are already people who have received the dose of UV-B that can cause this type of cancer. It is estimated that between 1979 and 1993, this type of UV-B dose increased by 8.9 percent at the 55th parallel north (roughly where Copenhagen and Moscow are); 11.1 percent at latitude 45°N (Venice and Montreal); and 9.8 percent at the 35th parallel north (Cyprus, Tokyo and Memphis). The average between latitudes 55° and 35°N was 10 percent and it is estimated that the increase was greater in the southern hemisphere. The United Nations Environment Program (UNEP) predicts that with annual ozone depletion of 10 percent for several decades, the increase in skin cancer cases will be about 250,000 per year. Even taking into account current agreements to phase out ozone-depleting substances (ODS), a realistic model would indicate that by 2050, skin cancer rates would rise to 25 percent above 1980 levels across the 50°N latitude. The deadliest skin cancer, known as melanoma, could also be increasing in frequency.
1.2 The immune system
A person’s defenses against infection depend on the strength of their immune system. Exposure to ultraviolet light is known to reduce the effectiveness of the immune system, not only for skin infections, but also for detectable infections elsewhere in the body.
UNEP emphasizes that the effects on the immune system are one of the most worrying issues and A points out that exposure to UV-B radiation could negatively affect immunity to infectious diseases. For example: leishmaniasis and malaria and fungal infections such as candida. Exposure to UV-B radiation may well cause the immune system to tolerate the disease instead of fighting it. This could mean that vaccination programs are useless in both developed and developing countries.
2. Aquatic ecosystems
The loss of phytoplankton, the basis of the marine food chain, has been observed to be the cause of the increase in ultraviolet radiation. Under the Antarctic ozone hole, phytoplankton productivity decreased between 6 and 12 percent. UNEP states that a 16 percent drop in ozone could result in a 5 percent loss of phytoplankton, which would mean a loss of 7 million tonnes of fish per year – about 7 percent of global fish production. 30 percent of human protein consumption comes from the sea, and in developing countries that proportion is rising even further.
3. Terrestrial ecosystems
In some species, an increase in UV-B radiation leads to the development of skin cancer. This has been studied in goats, cows, cats, dogs, sheep and laboratory animals and likely indicates that this is a common trait across species. Infections in cattle can be exacerbated by increases in UV-B radiation.
UV-B radiation can have the following harmful effects on many plants: It changes shape and damages plant growth. reduce tree growth; change flowering times; make plants more susceptible to diseases and produce toxic substances. There could even be loss of biodiversity and species. Soy and rice are among the crops reported to have negative effects from exposure to UV-B radiation.
4. Air pollution
Ozone losses in the upper atmosphere cause UV-B rays to increase ozone levels at the Earth’s surface, particularly in urban and suburban areas, reaching potentially harmful levels in the early morning hours.
Low-altitude ozone can cause respiratory problems and worsen asthma, as well as damage trees and some crops. In addition, low ozone levels contribute to the increase in acid rain problems.