Введение

You've probably heard of "acid rain". But you may not have heard of acid snow, acid fog or mist, acid gas and acid dust. All of these "acids" are related air pollutants, and can harm your health, cause hazy skies and damage the environment and your property. The 1990 Clean Air Act includes an innovative program to reduce acid air pollutants (all referred to here as "acid rain").

The acid rain that has received the most attention is caused mainly by pollutants from big coal burning power plants in the Midwest. These plants burn Midwestern and Appalachian coal, some of which contains a lot of sulfur compared to Western coal. Sulfur in coal becomes sulfur dioxide (S02) when coal is burned. Big power plants burn large quantities of coal, so they release large amounts of sulfur dioxide, as well as NOx (nitrogen oxides). These are acid chemicals, related to two strong acids: sulfuric acid and nitric acid.

The sulfur dioxide and nitrogen oxides released from the Midwestern power plants rise high into the air and are carried by winds toward the East Coast of the U.S. and Canada. When winds blow the acid chemicals into areas where there is wet weather, the acids become part of the rain, snow or fog. In areas where the weather is dry, the acid chemicals may fall to Earth in gases or dusts.

Lakes and streams are normally slightly acid, but acid rain can make them very acid. Very acid conditions can damage plant and animal life.

Acid lakes and streams have been found all over the country. For instance, lakes in Acadia National Park on Maine's Mt. Desert Island have been very acidic, due to pollution from the Midwest and the East Coast. Streams in Maryland and West Virginia, lakes in the Upper Peninsula of Michigan, and lakes and streams in Florida have also been affected by acid rain. Heavy rainstorms and melting snow can cause temporary increases in acidity in lakes and streams in the eastern and western United States. These temporary increases may last for days or even weeks.

Acid rain has damaged trees in the mountains of Vermont and other states. Red spruce trees at high altitudes appear to be especially sensitive to acid rain. The pollutants that cause acid rain can make the air hazy or foggy; this has occurred in the eastern United States, including some mountain areas popular with vacationers, such as the Great Smokies.

Acid rain does more than environmental damage; it can damage health and property as well. Acid air pollution has been linked to breathing and lung problems in children and in people who have asthma. Even healthy people can have their lungs damaged by acid air pollutants. Acid air pollution can eat away stone buildings and statues.

Health, environmental and property damage can also occur when sulfur dioxide pollutes areas close to its source. Sulfur dioxide pollution has been found in towns where paper and wood pulp are processed and in areas close to some power plants. The 1990 Clean Air Act's sulfur dioxide reduction program will complement health-based sulfur dioxide pollution limits already in place to protect the public and the environment from both nearby and distant sources of sulfur dioxide.

The Act takes a new nationwide approach to the acid rain problem. The law sets up a market based system designed to lower sulfur dioxide pollution levels.

Beginning in the year 2000, annual releases of sulfur dioxide will be about 40 percent lower than the 1980 levels. Reducing sulfur dioxide releases should cause a major reduction in acid rain.

Phase I of the acid rain reduction program goes 4 into effect in 1995. Big coal-burning boilers in 110 power plants in 21 Midwest, Appalachian,

Southeastern and Northeastern states will have to reduce releases of sulfur dioxide. In 2000, Phase II of the acid rain program goes into effect, further reducing the sulfur dioxide releases from the big coal-burning power plants and covering other smaller polluters. Total sulfur dioxide releases for the country's power plants will be permanently limited to the level set by the Clean Air Act for the year 2000.

Reductions in sulfur dioxide releases will be obtained through a program of emission (release) allowances. EPA will issue allowances to power plants covered by the acid rain program; each allowance is worth one ton of sulfur dioxide released from the smokestack. To obtain reductions in sulfur dioxide pollution, allowances are set below the current level of sulfur dioxide releases.

Plants may only release as much sulfur dioxide as they have allowances. If a plant expects to release more sulfur dioxide than it has allowances, it has to get more allowances, perhaps by buying them from another power plant that has reduced its sulfur dioxide releases below its number of allowances and therefore has allowances to sell or trade. Allowances can also be bought and sold by "middlemen", such as brokers, or by anyone who wants to take part in the allowances market. Allowances can be traded and sold nationwide. There are stiff penalties for plants which release more pollutants than their allowances cover.

The acid rain program provides bonus allowances to power plants for (among other things) installing clean coal technology that reduces sulfur dioxide releases, using renewable energy sources (solar, wind etc.) or encouraging energy conservation by customers so that less power needs to be produced.

All power plants under the acid rain program will have to install continuous emission monitoring systems (CEMS), machines that keep track of how much sulfur dioxide and nitrogen oxides the plant is releasing. A power plant's program for meeting its sulfur dioxide and nitrogen oxide limit will appear on the plant's permit, which will be filed with the state and EPA.

To cut down on nitrogen oxide pollution, EPA will require power plants to reduce their nitrogen oxide releases, and will require reductions in nitrogen oxide releases from new cars. Reducing nitrogen oxide releases will reduce both acid rain and smog formation.

The flexible market-based acid rain reduction program is expected to be a model for pollution control efforts in the United States and other countries.

When I was in grade 9, I did an experiment with ice cubes and water. I filled a glass to the top with ice cubes. Then I poured water in the glass. I filled it to the rim and let it set for a few hours. Amazingly enough, the water did not spill out of the glass. The water level actually decreased. It stands to reason that this will be the same thing that happens if the polar ice melts.

Polar ice is comprised of two different kinds of ice: 1) sea ice, which is formed from the freezing of sea water and which floats on the surface of the oceans, and 2) land-based ice (glaciers, ice caps and the massive ice sheets of Greenland and Antarctica) which is formed from the accumulation and compaction of snow. Since icebergs calve off of ice sheets and glaciers, their origin is also land-based ice.

Sea ice affects sea-level – just as melting ice affects water levels in a glass – but is not a cause of rising sea-levels. It is melting land based ice that is one factor in rising sea-levels.

Global sea-level has risen 10 to 20 centimetres in the past 100 years. Projections indicate that sea-levels will continue to rise between 10 and 90 centimetres over the next 100 years under a range of climate change scenarios.

Climate warming can cause sea-level to rise by thermal expansion since water expands as it warms. Thermal expansion has been the major cause of recent sea-level changes and is projected to be the largest component of sea-level rise over the next 100 years.

In addition, warming increases the melting of land-based ice, adding to the amount of water flowing into the oceans. Melting of mountain glaciers is expected to be the second largest contributor to sea-level rise over the next century. Although these glaciers make up only a small percentage of the world's land ice, they are more sensitive to climate warming than the massive, cold, ice sheets of Greenland and Antarctica. Most Arctic glaciers have been in decline since the early 1960s, with this trend speeding up in the 1990s.

Projections from global climate models suggest that the contribution of Arctic glaciers to global sea level rise will accelerate over the next 100 years. Over the long-term, the Arctic contribution to global sea-level rise is expected to increase, as the Greenland ice sheet responds to climate warming. Already there are signs of such a response. Maximum surface-melt area on the ice sheet increased on average by 16 per cent from 1979 to 2002. Complete melting of the Greenland Ice Sheet – a process that would likely take a thousand years or more – would raise sea level about 7 metres.

With an average temperature of -37°C in Antarctica, there is a much lower risk of melting at the South Pole even with substantial regional warming. Some concern has been expressed about the stability of the West Antarctic Ice Sheet. However, current ice dynamic models project that this ice sheet will contribute no more than 3 mm/yr to sea-level rise over the next thousand years.

How many tones of greenhouse gases are created by a forest fire per hectare?

Direct carbon emissions are a product of combusted fuel during a fire. From an average fire in Canada, 1.3 kilograms (kg) per square metre of carbon is released to the atmosphere. This is equivalent to 13 000 kg (13 tonnes) of carbon per hectare. Fires release carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrogen oxides and other particulate matter, but 80 to 90 per cent of the carbon released becomes carbon dioxide. On average in Canada, 2.6 million hectares of land are burned each year, releasing 34 million tonnes of carbon dioxide.

Although fossil fuel burning is the biggest contributor to increasing atmospheric greenhouse gases, emissions from a forest burning is also a major source of greenhouse gases. Emissions from such fires represent about 18 per cent of current Canadian carbon dioxide emissions.

Post-fire effects can cause additional losses of carbon and changes to the forest sink condition. Carbon sinks, areas where more carbon is stored than released, help stabilize atmospheric carbon dioxide through natural absorption and storage. Forests play an important role in this process. When forests burn, carbon sinks burn as well, so carbon dioxide does not get stored by the forest and is released into the atmosphere. Decomposing organic material left in the wake of the fire also releases carbon dioxide.

However, fire plays an important role in most forest ecosystems in Canada, helping to maintain the health and diversity of a forest.

Saiga (Saiga tatarica tatarica) - a unique migrant mammal that in the course of long evolution has well adapted to complicated habitat conditions in dry deserts and semi-deserts of Eurasia. Despite the relatively short life expectancy these animals have extremely high reproduction speed. This allows the population rehabilitate itself after the periods of high mortality caused by environmental stresses.

Quite recently this antelope was a common inhabitant of European and Central Asian steppes and semi-deserts. In Russia saiga could be found on the right bank of Volga in its lower reaches (territory of modern Republic of Kalmykiya and Astrakhan' region). Yet, in the process of human development of these areas, number and range of the population has been steadily decreasing.

However saiga remained numerous in Russia and Kazakhstan right up to the middle of the last century. Exactly from this moment tendency towards drastic population number decline resulting from increase of cattle load on pastures, degradation of habitats and anthropogenic stress could be traced. Urgent measures taken in 1970s to limit saiga hunting helped recruit number of animals to the level of 1950-s (700-800 thousands individuals) after which decrease recommenced.

Today, excessive and unregulated saiga hunting represents the biggest threat to the animal - its meat and especially horns are highly valued and demanded in traditional Chinese medicine. Another cause is disturbance of key habitats and usual saiga's migration routes. Saved from almost complete extinction in the middle of XX century, saiga populations are found to be endangered again. Now overall size of saiga population in Russia is extremely low and doesn't exceed 18 thousands individuals, with adult males making up from 1 to 10% (in "better" times). Thus, current situation is close to critical.

Saiga was included in the Annex to the II Convention on Migratory Species at the 7th conference of member-states (Bonn, Germany, September 2002) Also IUCN (International Union for Nature Conservation) categorized this specie in its Red List as "endangered" (2002).

Russian Committee for the UNESCO program "Man and Biosphere" (MAB), Laboratory of Mammal Landscape Ecology (Institute of Environmental and Evolution Problems, Russian Academy of Sciences), Biodiversity Conservation Center and other interested organizations are planning to develop and implement a system of measures aimed at preventing this unique specie from extinction.

Providing citizens with reliable and timely information, raising public awareness of the problem of saiga protection now takes on special significance. This page contains many useful materials on this issue.

The probability of precipitation (POP) is the chance that measurable precipitation — at least 0.2 mm of rain or 0.2 cm of snow — will fall on any point of the forecast region (such as the city of Ottawa) during the forecast period. For example, a 70 per cent probability of precipitation in Ottawa means that the chance of you getting rained on (or snowed on in winter) is 7 in 10. In other words, there is a 70 per cent chance that rain or snow will fall on you, and therefore, a 30 per cent chance that it won't.

Probability forecasts cannot be used to predict when, where or how much precipitation will occur. For example, a 60 per cent probability of snow today does not mean that it will snow during 60 per cent of the day. However, the probability figure does mean that there is a 60 per cent chance of a measurable amount of snow falling at that location.

A person who did not encounter precipitation during the time period would be tempted to say the forecast probability should have been zero; while someone else who did see precipitation during the same period would say the probability should have been 100 per cent. Statistically, one cannot determine the reliability of a single probability forecast. The reliability can only be verified after a number of forecasts. A 30 per cent probability of precipitation forecast is reliable if the same forecast was made on one-hundred occasions and if it rained on 30 of those occasions.

The weather office forecasts a probability of precipitation for your region based on the information available at the time the forecast is issued. As the time of the event nears, and more information becomes available, the prediction becomes more accurate.

Weather is an incredibly complex phenomenon. Despite the use of computers, radars, satellites and skilled forecasters, it is still difficult to forecast future precipitation. So unfortunately, rain or snow cannot always be predicted with a simple yes or no.

What is the procedure for cleaning up oil spills? What equipment is used?

There is usually a contingency plan already in place for a region or body of water. This includes an action plan, list of contacts, probable oil movement patterns, and technical data such as "sensitivity maps" which outline areas that are ecologically sensitive and therefore most in need of protection. When an oil spill occurs, the potential impacts of the spill are evaluated, and workers try to control it as quickly as possible. Different types of equipment are used to track the movement of the oil, such as low-flying planes or helicopters, infrared and ultraviolet cameras, computerized tracking and dispersion simulation models, tracking buoys which drift with the oil and transmit their location by radio & satellite, radar, microwave and laser-induced fluorescence. To prevent the oil from spreading, floating booms (mechanical barriers placed in the water to stop the flow of the oil) or sorbent booms and barriers (porous material used to absorb an oil slick) are used. Once the oil spill has been contained, there are a number of methods used to recover the oil from the surface of the water. Skimmers are used to mechanically remove the oil without creating major biological or chemical changes to the water. Sweep systems, a combination skimmer and boom, are attached to a ship or boat. As the vessel moves forward, this system contains and collects the spilled oil, which is then pumped into storage tanks. Sorbents are materials that soak up the oil. These can be natural like peat moss or sawdust, or synthetic like polypropylene or polyester foam. Once the absorbent material has been applied to the oil, the mixture is recovered with the aid of nets, rakes, forks or pike poles. Manual recovery is another common method especially for areas with a high concentration of oil. Buckets and shovels are used to remove the oil. Once the oil has been recovered, it is separated from the water, often by using settling tanks, and disposed of through re-refinery, burning, or other methods. Clean-up and restoration For the clean-up and restoration of shorelines from oil spills, many people trained for the job usually pitch in with simple hand tools (e.g. rakes, shovels, wheelbarrows, garbage bags, high and low-pressure hoses and absorbent material) to clean up. This process must be done carefully in order to avoid unnecessary erosion and damage of the shoreline. Generally, three methods can be used to clean oil off the shoreline: chemical and hydraulic dispersion: chemical clean-up agents or high-pressure water hoses are used to wash oil from coarse sediments, rock surfaces and artificial structures; low-pressure water flushing removes oil from fine sediments, shores with vegetation and marshes; steam cleaning: steam is used to clean artificial structures and rock faces; removal: using graders and scrapers for large quantities of oil on the shoreline. Skilled emergency crews work quickly to rescue any wildlife that have been affected by an oil spill. Even a relatively small oil spill can have a dramatic impact on bird and animal populations. Therefore, even though this requires a lot of time and effort, is costly, and has a low success rate, it is an important part of the process Sometimes, it is deemed best not to respond to an oil spill in certain areas, for one of three reasons: the oil spill occurred in a sensitive environment; natural processes would be faster and more effective than human efforts; and high-energy wave energy may break the oil up more effectively.

Most of our garbage is sent to landfills, dumps or municipal incinerators. But with more and more people producing more and more waste, landfills are filling up faster than we can find new sites for them. And landfills create new types of waste. As garbage decomposes, moisture filters through it producing a toxic liquid known as leachate. Modern landfills are designed to reduce the amount of moisture that reaches the garbage, and many have a system to collect and treat the leachate.

Decomposing garbage also produces two greenhouses gases: carbon dioxide and methane, an invisible, odourless, and highly flammable gas. Landfill sites account for about 38 per cent of Canada's total methane emissions. Methane is 20 times more potent as a greenhouse gas that carbon dioxide. At some big landfill sites in Canada, methane is now being collected and burned to produce energy.

Water and oxygen are required to break down garbage. But water and oxygen are in short supply deep in a landfill, so decomposition takes place very slowly. In fact, when researchers cored down into a landfill in the United States, they discovered newspapers over 30 years old still in readable condition!

Incinerators are sometimes used to burn solid waste under controlled conditions. They reduce the stress on landfills, but they create other environmental problems. The ashes must be disposed of, either at a landfill, or, if they are toxic, at a hazardous waste facility. Burning garbage also produces acid gases, carbon dioxide and toxic chemicals that must be treated with expensive air pollution control equipment to avoid contributing to acid rain, ozone depletion and air pollution.

Recycling is just one way to reduce wastes. To be really effective, we have to incorporate the 4Rs Reduce, Reuse, Recycle and Recover into our daily routine. Reducing the amount of waste we produce is by far the most effective way to battle the flow of garbage into the landfill. Packaging makes up about half our garbage by volume, one-third by weight.

Avoid food packaged in individual servings. Buy in bulk. It saves money and the environment.

Buy what you recycle. Recycling doesn't end with collecting our recyclables. To "close the loop" we need to turn those materials into new usable products, and to ensure a market for those products.

Outdoor air pollution comes from both natural and human sources. Natural sources include smoke from forest fires, wind-blown dust from soil and volcanoes, bacteria, fungi and chemicals released by plants and animals.

However, air pollution is primarily associated with daily human activities. Pollutants are released by motor vehicles, industrial processes (pulp and paper mills, ore smelters, petroleum refineries, power generating stations and incinerators), and the burning of fossil fuels such as gas, oil, coal and wood. Paints, pesticides and products that contain certain chemicals are other sources of air pollutants.

Air pollutants can be carried thousands of miles across borders and oceans and from one urban area to another. This phenomenon is common around the world and is known as "long-range atmospheric transport" or "transboundary pollution".

The most commonly measured outdoor air pollutants in Canada include ground-level ozone, particulate matter, carbon monoxide, sulphur dioxide and nitrogen oxides. These substances are the principal ingredients or precursors of smog, and some also contribute to acid rain.

Экономическая теория выступает в качестве методологического фундамента сложного комплекса экономических наук и оказывает значительное влияние на развитие социальных наук. Вместе с тем, как справедливо отмечал английский экономист Джон Мейнард Кейнс, экономическая теория - не есть набор уже готовых рекомендаций, применимых непосредственно в хозяйственной политике. Она является скорее инструментом, техникой мышления, помогая тому, кто владеет ею, приходить к правильным заключениям.

Представляется, что будущее за разносторонне грамотными специалистами, которые не только в курсе современных проблем, но знакомы и с теоретическим и практическим опытом предшественников. Все это делает очень важным для будущих экономистов, менеджеров, финансистов, бухгалтеров изучение политической экономии как методологической основы практического экономического знания.

Поэтому первым этапом изучения экономических дисциплин выступает такая фундаментальная экономическая дисциплина как «Политическая экономия». Она знакомит будущих специалистов с наиболее общими аспектами функционирования экономических систем и подготавливает основу для успешного усвоения содержания других общеэкономических, а в последующем функциональных и отраслевых экономических дисциплин.

Настоящие планы семинарских занятий в равной степени рекомендованы для студентов всех экономических специальностей. В них в полном соответствии с Типовой программой по политической экономии, Рабочей программой по политической экономии для студентов экономических специальностей Севастопольского национального технического университета, к каждому семинарскому занятию приводится план темы, блок новых терминов и понятий, знание которых является необходимым условием квалифицированного обсуждения вопросов.

Дополнительными формами проверки степени усвоения теоретического материала по той или иной теме являются выполнение тестовых заданий и решение задач.

Все студенты в процессе изучения политической экономии в течение первого семестра на первом курсе обязаны подготовить выступление по той или иной реферативной теме. Темы докладов прилагаются к каждому плану семинарских занятий. С целью активизации самостоятельной работы студентов конкретный список литературы к рефератам не приводится, студент обязан, используя библиотечный фонд, ознакомившись с несколькими источниками учебной и периодической экономический литературы, подготовить выступление на ту или иную тему.

В конце планов семинарских занятий приводятся список учебной литературы, к которой студенты обращаются при подготовке к семинарским занятиям.