A study of ozone layer and the growing problem of depletion
These changes can have important implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles. The list should include name of ODS, type and location of equipment, quantity in kg and date.
Ozone layer depletion introduction
Consumption fell by more than 60 percent by ; 80 percent by ; and by percent by Since its first draft in , the Montreal Protocol has undergone numerous amendments of increasing ambition and reduction targets. For many substances, this timeframe is on the scale of decades up to a century. By combining epidemiological data with results of animal studies, scientists have estimated that every one percent decrease in long-term stratospheric ozone would increase the incidence of these cancers by two percent. Ozone concentrations in the lower stratosphere over Antarctica will increase by 5—10 percent by and return to pre levels by about — At the Northern poles, this was much less at between 5 to 10 percent. It is formed of three oxygen atoms giving it the chemical formula, O3. The chlorine atoms act as a catalyst , and each can break down tens of thousands of ozone molecules before being removed from the stratosphere. This replacement was therefore been an important reduction strategy particularly where the complete phase-out of ozone depleting substances was not readily available. Environmental Protection Agency, eradicating ozone much more quickly than it can be replaced. This was the reason for the Montreal Protocol. There are no significant trends in the tropics, largely because halogen-containing compounds have not had time to break down and release chlorine and bromine atoms at tropical latitudes. The lifetime of gases in the atmosphere play an important role in understanding how their concentrations change over time. Throughout the s and first half of the s, chlorofluorocarbons CFCs dominated global consumption accounting for 60 percent, reducing to 50 percent. These changes can have important implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles.
That same year, the discovery of the Antarctic ozone hole was announced, causing a revival in public attention to the issue. We do not expect very short-lived substance emissions to significantly influence the ozone hole unless they increase drastically, but this is one more reason to keep an eye on them.
A study of ozone layer and the growing problem of depletion
The report concluded that depleted ozone levels around the mid-latitudes of the planet are already endangering large populations in these areas. These low temperatures form cloud particles. In contrast, solving a problem as wide reaching as global climate change involves changing many aspects of our economic and social systems. Effects on Materials Synthetic polymers, naturally occurring biopolymers, as well as some other materials of commercial interest are adversely affected by UVB radiation. Farman , Brian G. In the figure below we show the average percentage change in UV irradiation reach the surface in relative to levels in The role of sunlight in ozone depletion is the reason why the Antarctic ozone depletion is greatest during spring. The "hole" is actually an area of the stratosphere with extremely low concentrations of ozone that reoccurs every year at the beginning of the Southern Hemisphere spring August to October.
Ozone depletion and the subsequent increase in UV-B irradiation, as discussed abovecan increase negative health impacts such as skin cancerand other implications such as sunburn and skin ageing. The sum of all of halogen gases in ODP tonnes provides a total measure of ozone-depleting substance emissions.
What is ozone layer depletion and its effects?
Blue trends map the estimated impact had the Montreal Protocol not been adopted: it is based on the assumption of a 2 to 3 percent dashed and solid line increase in annual production of halogen substances. The total amount of effective halogens chlorine and bromine in the stratosphere can be calculated and are known as the equivalent effective stratospheric chlorine EESC. Emissions vs. They examined ozone changes within 60 degrees of the equator, not over the Antarctic. The data collected in the report showed that a lack of sunlight allowed CFCs to collect around the ozone layer above Antarctica in the winter. Ozone depletion and the subsequent increase in UV-B irradiation, as discussed above , can increase negative health impacts such as skin cancer , and other implications such as sunburn and skin ageing. The "ozone hole" is more of a depression, less "a hole in the windshield". However they resonated better with non-scientists and their concerns. Ground-level ozone can form through chemical reactions between local air pollutants such as nitrous oxides NOx , volatile organic compounds VOCs and sunlight. Emissions of ozone-depleting chemicals in places like China are especially damaging because of cold-air surges in East Asia that can quickly carry industrial pollution into the tropics. Exposure to UVB radiation is linked with increased risk of skin cancer and cataracts, as well as damage to plants and marine ecosystems. Further work by Susan Solomon and colleagues clearly attributed the ozone hole to CFCs and other ozone-depleting chemicals that contained the elements chlorine and bromine.
Although ozone depletion has been a global issue, there is significant differences in distribution of ozone layer depletion across the world. The participants agreed to phase out CFCs and halons entirely aside from a very small amount marked for certain "essential" uses, such as asthma inhalers by in non-Article 5 countries and by in Article 5 less developed signatories.
The dot is a notation to indicate that each species has an unpaired electron and is thus extremely reactive. At the time, CFCs were commonly used in aerosol sprays and as coolants in many refrigerators. Atmospheric measurements have clearly corroborated theoretical studies showing that chlorine and bromine released from halocarbons in the stratosphere react with and destroy ozone.
Human activities that cause ozone depletion
Their analyses attracted the attention of the scientific community , which found that these decreases in the total ozone column were greater than 50 percent compared with historical values observed by both ground-based and satellite techniques. Furthermore, new ODS supply or landing to shore facilities should be recorded as well. In the chart below we show the absolute concentrations of CFC as opposed to the annual rate of change, shown above in terms of actual measurements solid lines, for both hemispheres and projections dashed line. These gases, emitted at the surface, are distributed globally through the lower atmosphere through wind transport patterns. Impacts on skin cancer risk Ozone layer protection from UV-B irradiation is critical to the health of many lifeforms, including human health. Since more ozone loss occurred than could be explained by the supply of reactive chlorine available in the polar regions by known processes at that time, other hypotheses arose. In the Vienna Convention for the Protection of the Ozone Layer was adopted and entered into force in This converts a single O 2 into two atomic oxygen radicals. Further warming temperatures near the end of spring break up the vortex around mid-December. Arctic ozone decreases of as much as 40 percent have been measured. Total column ozone declined below pre values between and for mid-latitudes. One of the first studies to attempt to quantify excess skin cancer cases, despite being published in the s correlates well with results from recent studies. This is an important goal because stratospheric ozone protects us from exposure to ultraviolet radiation, which can increase the risk of cataracts, skin cancer and other detrimental effects.
Although considerable variability is expected from year to year, including in polar regions where depletion is largest, the ozone layer is expected to begin to recover in coming decades due to declining ozone-depleting substance concentrations, assuming full compliance with the Montreal Protocol.
This was the reason for the Montreal Protocol. The increased UV light leads to skin cancer, cataracts, and harm to aquatic organisms.
If the chemicals that were now discovered in unexpectedly large amounts can reach the ozone layer in significant quantities, they can cause damage.
based on 94 review