- •Lecture 8 Topic: Water resources problems
- •1. Importance of Water for Life
- •2. Ecological consequences of water deficiency and water pollution
- •3. Sources of water pollution
- •4. Sustainable strategies on water resources problem. International cooperation
- •Lecture 9
- •Scheme: An overview of the ecological issues
- •3. Ecological crisis and ecological situations
- •4. Modern Ecological crisis: Pollution.
- •6. Global energy balance and Greenhouse effect.
- •7. Global warming, its sources and solving the problem of sustainably. International cooperation on climate change problem.
- •Population stability, Reforestation, Recycling, Energy efficiency, Renewable energy technologies
- •International cooperation on climate change problem
- •Lecture 10 Topic: Stratosphere Ozone Depletion. Acid Rains.
- •1. The nature of ozone and mechanism of ozone layer work
- •2. Ozone depletion: history, sources & the effects of ozone layer destruction
- •3. Air pollution wet & dry smog, indoor pollution
- •Indoor air pollution. Public health problem
- •4. The nature, source & the effects of acid rain.
- •5. Sustainable strategies on ozone layer & acid rain problems. International cooperation
- •Industries can help to prevent further damage to the ozone layer:
- •International cooperation on acid rains control
- •Lecture 11
- •1. Human populations:
- •2. Population growth. Limits to Growth.
- •3. Basic demographic processes:
- •Lecture 12 Topic: Economic aspects of environmental sustainability
- •3. Concept of externalities
- •5. Solutions of reducing poverty
- •6. Sustainable strategies on economy
6. Global energy balance and Greenhouse effect.
Energy input is balanced by energy output. Visible light from the sun passes through the atmosphere to the earth’s surface. Heat radiation leaves earth. Some escapes, but gases in the atmosphere trap the rest, keeping the earth warm (t = + 15°C)
Albedo – a measure of the reflectivity of a body or surface (in %). This is essential to the earth’s climate and makes life on earth possible. This is what we describe as the “greenhouse effect”.
Greenhouse effect – mechanism that explains atmospheric heating caused by increasing carbon dioxide. CO2 is believed to act like the glass in a greenhouse, permitting visible light to penetrate but impeding the escape of infrared radiation, or heat.
A large proportion of the sun’s energy which reaches the earth’s atmosphere then bounces strait back into space. The rest of the sun’s energy stays in the earth’s atmosphere, where it is absorbed by gases and scattered back to space or down to earth.
A build-up of gases, including carbon dioxide and CFCs, prevents additional heat from escaping, thus heating up the earth excessively.
Greenhouse gases – naturally occurring or anthropogenic gases that trap heat escaping from the Earth’s surface, causing the atmosphere to heat up. They include: CO2 – the main greenhouse gas, chlorofluorocarbons (CFC) and Halons, Methane (CH4), Nitrous oxides (NOx), Tropospheric (ground) ozone (O3), Water vapor (H2O).
7. Global warming, its sources and solving the problem of sustainably. International cooperation on climate change problem.
Global warming – the warming of the Earth’s atmosphere caused by the build up of greenhouse gases. It is the warming of the Earth’s biosphere resulting from human-induced increases in greenhouse gases including carbon dioxide, methane and nitrous oxide, in the atmosphere.
The greenhouse effect has started to cause concern because the concentration of greenhouse gases in the atmosphere is increasing. Since 1850 it has increased by almost 30%, mainly due to the burning of fossil fuels, such as coal and oil, by humans. This is known as “global warming”.
The global mean temperature is the average temperature of the earth, and it changes over time. Scientists now predict that the global mean temperature will rise by 1oC in 2025, and by 3oC by 2100. This may not sound very much, but it is bigger increase than the increase that has occurred since the ice age!
It is difficult to predict exactly what effects the rise in temperature will have. Many people agree that there are likely to be changes in the climate in different parts of the world – some places may get hotter and drier, others cooler and wetter. Such changes may make it difficult to grow food and will affect wild plants and animals.
World energy use. Sources of global warming.
Influence of human activity to global warming: Energy use (57%), Industry (20%), Agriculture (14%), Deforestation (9%).
People activities of all kind contribute to global warming if:
- They burn any “fossil fuel” e.g. coal, oil, or gas as a source of energy. Burning these fuels gives off carbon dioxide and nitrous oxides (this applies to homes and schools as well as to industries).
- They use cars and lorries, or any form of transport, which runs on a form of fossil fuel (petrol and diesel are made from oil). Pollution from traffic also reacts with sunlight to form tropospheric (ground) ozone – another greenhouse gas.
- They use electricity.
- They use CFC or halons for any purpose: CFC are used: as coolants in refrigerators, freezers and air conditioning; as solvents for a wide variety of uses; to make products such as foams and aerosols. Halons are used mainly for fire extinguishers.
- They produce any organic wastes, which are buried in landfill sites. These produce the greenhouse gas methane as they rot down (wetlands, rice, livestock).
- They use fertilizers which give off nitrous oxides.
- They use products from rainforest trees (such as veneers, timber and pulp) or from rainforest land (such as minerals or cattle products). Trees absorb carbon dioxide, and rainforest are one of the world’s most important absorbers of carbon dioxide enters the atmosphere. Burning trees also releases CO2 into the atmosphere.
Prevention measure of global warming includes the following strategies: