CFC and Ozone Destructuion

CFC s were commonly used as refrgerents and as propellant in spry cans.when these compounds escape into the atmosphere,it reaches the stratosphere intact as they are basically inert compounds.In the stratosphere,the CFC s are broken down by the sunlight releasing chlorine atoms.These chlorine atoms act as a catalyst in the destruction of o3 as shown.The plausible catalytic reactions leading to the destruction of ozone involves chlorine (cl) and (clo) as an intermediatary.

Formation of ozone

Ozone is formed in the atmosphere when ultra violet radiation from the sun strikes the stratosphere,splitting oxygen molecules(02) in to atomic oxygen (o).The atomic oxygen quickly combines with further oxygen molecules to form ozone.

At Ground Level,ozone is a health hazard and is a major constituent of photochemical smog.However,in the stratosphere we need ozone to absorb some of the potentially harmful ultra-violet(UV) radiation from the sun (at wavelength between 240 and 320 nm) which can cause skin cancer and damage vegetation.

Ozone Layer

Ozone (o3) occurs naturally in the atmosphere.The earth's atmosphere is composed of several layers.We live in the Troposphere where most of the weather occurs;such as rain,snow and clouds.Above the troposphere is the Stratosphere;an important region in which effects such as the ozone Hole and Global warming orginate.

Sun Kills 60,000 a Year, Says WHO

As many as 60,000 people a year die from too much sun, warns the World Health Organization. The bulk of the deaths are from skin cancer caused by excess exposure to the sun’s harmful rays, ultraviolet radiation, say WHO. UVR also causes sunburn, triggers cold sores and ages the skin, according to its report, the first to outline the global
health burden of sun exposure. Simple measures, such as covering up when in the sun, could cut the deaths.Dr Maria Neira, Director for Public Health and the Environment at WHO, said: "We all need some sun, but too much sun can be dangerous - and even deadly. "Fortunately, diseases from UV such as malignant melanomas, other skin cancers and cataracts are almost entirely preventable through simple protective measures." Of the 60,000 deaths, 48,000 are caused by malignant melanomas and 12,000 by other skin cancers, the report Global Burden of Disease of Solar Ultraviolet Radiation estimates. More than 1.5 million "disability-adjusted life years" or DALYS - a measure of the loss of full functioning due to disease and death - are lost every year due to sun exposure, WHO believes. WHO and the World Tourism Organization of the United Nations are urging people to be extra-vigilant when out in the sun to protect them from UVR Everyone is exposed to UVR from the sun. Small amounts are beneficial to health, and play an essential role in the production of vitamin D by the skin. However, overexposure to UVR is associated with a variety of serious and deadly health problems.

Rising Sea Level

UN Climate scientists Predicted that The world’s sea level rise twice as high this century as previously predicted, The Intergovernmental Panel on Climate Change proposes a maximum sea level rise of 81cm (32in) this century. But in the journal Nature climate scientists, researchers say the true maximum could be about twice that: 163cm (64in). They looked at what happened more than 100,000 years ago - the last time Earth was this warm. The results join other Studies showing that current sea level projections may be very conservative. Sea level rise is a key effect of climate scientists. There are two major contributory effects: expansion of sea water as the oceans warm, and the melting of ice over land. In the latest study, researchers came up with their estimates by looking at the so-called interglacial period, some 124,000 to 119,000 years ago, when Earth’s climate was warmer than it is now due to a different configuration of the planet’s orbit around the Sun. That was the last time sea levels reached up to 6m (20ft) above where they are now, filled by the melting of ice sheets that covered Greenland and Antarctica.

The Bali Declaration

The 2007 IPCC report, compiled by several hundred climate scientists, has unclearly concluded that our climate is warming rapidly, and that we are now at least 90 per cent certain this is mostly due to human activities. The amount of carbon dioxide in our atmosphere now far exceeds the natural range of the past 650,000 years, and it is rising very quickly due to human activity.

If this trend is not halted soon, many millions of people will be at risk from extreme events such as heat waves, drought, floods and storms, our coasts and cities will be threatened by rising sea levels, and many ecosystems, plants and animal species will be in serious danger of extinction.The next round of focused negotiations for a new global climate treaty (within the 1992 United Nations Framework Convention on Climate Change process) needs to begin in December 2007 and be completed by 2009.

The prime goal of this new regime must be to limit global warming to no more than 2C [3.6F] above the preindustrial temperature, a limit that has already been formally adopted by the European Union and a number of other countries.Based on current scientific understanding, this requires that global greenhouse gas emissions need to be reduced by at least 50 per cent below their 1990 levels by the year 2050.

In the long run, greenhouse gas concentrations need to be stabilized at a level well below 450 parts per million (measured in CO2-equivalent concentration). In order to stay below 2C, global emissions must peak and decline in the next ten to fifteen years, so there is no time to lose.As scientists, we urge the negotiators to reach an agreement that takes these targets as a minimum requirement for a fair and effective global climate agreement.

The Neglected Danger-Global Warming

Since 1980, the average global temperature has risen 0.2 degree Celsius each decade. Scientists predict that if we continue putting the same amount of green house gases into the atmosphere, that by the year 2030 the temperature will be rising as much as 0.5 degree C or more per decade.

Overall, the global temperature could rise anywhere from 5 to 9 degree over the next fifty years. if the temperature do rise, as predicited,several things could happen. The increase of temperature could alter the growth of crops in areas near the equator due to insufficient rain and heat. They could invariably destroy small islands, coastals cities and some shallow rivers.

Another cause of global warming is deforestation. Trees are being cut down mercilessly for man’s mere pleasure and for fulfilling his needs and wants. But the real consequences are a real danger for man kind. This problem of global warming due to deforestation can be solved by means of afforestation.but if not done; the earth and its inhabitants will become victims of global warming. And finally, a very important cause for this is, "the green house effect"-the green house gases carbon coming out from various industries and reaching the atmosphere and slowly depleting the ozone layer.

This may have harsh effects on the climate of the world. I believe global warming is a big threat to our nation and the world. If we do not act now, it may be too late. Although there is no sure way of telling what the climate will be like in the future we must take steps to ensure the health of the earth. If u look at what is happening to this world and u will see that there is a pollution problem. There are steps being taken to reduce the amount of green house gases put into the air. but it still is not enough, we need to do more to reduce global warming, if we don't do it now, future generations will suffer the effects of global warming.