Text 6. The Greenhouse Effect. Global Warming.

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The Greenhouse Effect, also referred to as global warming, is generally believed to come from the build up of carbon dioxide gas in the atmosphere. Carbon dioxide is produced when fuels are burned. Plants convert carbon dioxide back to oxygen, but the release of carbon dioxide from human activities is higher than the world's plants can process. The situation is made worse since many of the earth's forests are being removed, and plant life is being damaged by acid rain. Thus, the amount of carbon dioxide in the air is continuing to increase. This buildup acts like a blanket and traps heat close to the surface of our earth. Changes of even a few degrees will affect us all through changes in the climate and even the possibility that the polar ice caps may melt. (One of the consequences of polar ice cap melting would be a rise in global sea level, resulting in widespread coastal flooding.)

The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect. The greenhouse effect is the heating of the surface of a planet or moon due to the presence of an atmosphere containing gases that absorb and emit infrared radiation. Thus, greenhouse gases trap heat within the surface-troposphere system. This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection. The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.

In the absence of the greenhouse effect and an atmosphere, the Earth's average surface temperature of 14 °C could be as low as − 18 °C, the black body temperature of the Earth. Global warming, a recent warming of the Earth's surface and lower atmosphere, is believed to be the result of an " enhanced greenhouse effect" mostly (more than 50%) due to human-produced increases in atmospheric greenhouse gases. This human induced part is refered to as anthropogenic global warming (AGW).

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C during the last century. The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation. The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanoes produced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward. These basic conclusions have been endorsed by more than 40 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries.

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature will probably rise a further 1.1 to 6.4 °C during the twenty-first century. The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. Some other uncertainties include how warming and related changes will vary from region to region around the globe. Most studies focus on the period up to the year 2100. However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.

An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.

Political and public debate continues regarding climate change, and what actions (if any) to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Text 7. Flyash.

With the boom in population and industrial growth, the need for power has increased manifold. Nearly 73% of India’s total installed power generation capacity is thermal, of which 90% is coal-based generation, with diesel, wind, gas, and steam making up the rest. Thermal power generation through coal combustion produces minute particles of ash that causes serious environmental problems.

Commonly known as fly ash, these ash particles consist of silica, alumina, oxides of iron, calcium, and magnesium and toxic heavy metals like lead, arsenic, cobalt, and copper.

The 80-odd utility thermal power stations in India use bituminous coal and produce large quantities of fly ash. According to specialists, up to 150 million tonnes of fly ash were produced in India in the year 2000, primarily by thermal power plants and, to a lesser extent, by cement and steel plants and railways. This poses problems in the form of land use, health hazards, and environmental dangers. Both in disposal and in utilization utmost care has to be taken to safeguard the interest of human life, wild life, and such other considerations.

The prevalent practice is to dump fly ash on wastelands, and this has lain to waste thousands of hectares all over the country. To prevent the fly ash from getting airborne, the dumping sites have to be constantly kept wet by sprinkling water over the area. The coal industry in USA spends millions of dollars on lining fly ash dumping grounds. But in India, these sites are not lined and it leads to seepage, contaminating groundwater and soil. It lowers soil fertility and contaminates surface and ground water as it can leach into the subsoil. When fly ash gets into the natural draining system, it results in siltation and clogs the system. Fly ash interferes with the process of photosynthesis of aquatic plants and thus disturbs the food chain. Besides, fly ash corrodes exposed metallic structures in its vicinity.

Fly ash management has taken considerable strides over the past few years. Researches have been attempting to convert this waste into wealth by exploring viable avenues for fly ash management. Fly ash is oxide-rich and can be used as the raw material for different industries.

Today, fly ash bricks can be used as a building material. The American Embassy in India has used fly ash bricks in some of its recent construction. Use of fly ash as a part replacement of cement in mortar and concrete has started with the Indian Institute of Technology, Delhi taking the lead. Use of fly ash in the construction of roads and embankments has been successfully demonstrated in the country and it is gaining acceptance. The NTPC (National Thermal Power Corporation) is setting up two fly ash brick manufacturing plants at Badarpur and Dadri near Delhi.

Researchers have proven that fly ash dumps can be reclaimed by suitable addition of organic matter and symbiotic fungi, making it commercially viable for activities like floriculture and silviculture. The researchers have successfully reclaimed a part of an ash pond at the Badarpur Thermal Power Station by introducing a mycorrhizal fungi-based organic bio-fertilizer. It improves the plant's water and nutrient uptake, helps in the development of roots and soil-binding, protects the plants from soil-borne diseases, and detoxifies contaminated soils. This helps in keeping both air and water pollution under control. It also helps revive wastelands and saves millions of litres of precious water from going down the fly ash slurries.

After you read Text 6 and 7

· Complete the following sentences according to the context:

1. An increase in global temperature will cause ………………………………..

2. The defining characteristic of the greenhouse effect is ………………………

3. ……………………. cause such a serious environmental problem as fly ash.

4. Fly ash dumps can be reclaimed by ………………………………………….

5. Carbon dioxide amount increase acts like a ………………………………….

Before you read Texts 8 and 9

· What are air pollution effects you feel almost every day?

· What do you think is necessary to do to reduce air pollution?

As you read Texts 8 and 9. Read these questions and choose the best answer:

1. According to the text 8 the extent of air pollution harm on a man depends on

A the air pollution control technologies and land use planning;

B the duration of exposure and the concentration of the chemicals.

2. The term exposure in the text 8 means:

A the state of being in a place or situation where there is no protection from something harmful;

B the state of having the true facts about somebody or something told after they have been hidden because they are bad.

3. Land use planning is a very important part of social policy, because:

A it reduces pollution from mobile sources and increases fuel efficiency;

B it ensures that land is used efficiently for the benefit of the wider economy and population as well as to protect the environment.

Text 8. Health Effects.

Air pollution can affect our health in many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals, i.e., the duration of exposure and the concentration of the chemicals must be taken into account.

Examples of short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. In the great " Smog Disaster" in London in 1952, four thousand people died in a few days due to the high concentrations of pollution.

Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly. It is estimated that half a million people die prematurely every year in the United States as a result of smoking cigarettes.

The World Health Organization states that 2.4 million people die each year from causes directly attributable to air pollution, with 1.5 million of these deaths attributable to indoor air pollution. " Epidemiological studies suggest that more than 500, 000 Americans die each year from cardiopulmonary disease linked to breathing fine particle air pollution." A study by the University of Birmingham has shown a strong correlation between pneumonia related deaths and air pollution from motor vehicles. Worldwide more deaths per year are linked to air pollution than to automobile accidents. Published in 2005 suggests that 310, 000 Europeans die from air pollution annually. Direct causes of air pollution related deaths include aggravated asthma, bronchitis, emphysema, lung and heart diseases, and respiratory allergies.

Effects on children. Cities around the world with high exposure to air pollutants have the possibility of children living within them to develop asthma, pneumonia and other lower respiratory infections as well as a low initial birth rate. Research by the World Health Organization shows there is the greatest concentration of particulate matter particles in countries with low economic world power and high poverty and population rates. Examples of these countries include Egypt, Sudan, Mongolia, and Indonesia. The Clean Air Act was passed in 1970, however in 2002 at least 146 million Americans were living in areas that did not meet at least one of the “criteria pollutants” laid out in the 1997 National Ambient Air Quality Standards. Those pollutants included: ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. Because children are outdoors more and have higher minute ventilation they are more susceptible to the dangers of air pollution.

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