Acid Rain, Global Warming, Ozone Depletion

Global Warming, Acid Rain, and Ozone Depletion

EnvironmentalStudies Studies, Environmental , 2e2e OxfordUniversity UniversityPress Press2011 2011 ©©Oxford

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Chapter Objectives After studying this chapter, the reader should be able to: • Explain the causes and effects of acid rain • Describe the problem of ozone layer depletion and formation of the ozone hole over the Antarctic • Outline the provisions of the Vienna Convention and the Montreal Protocol • Describe the results of implementation of the Montreal Protocol and the lessons learnt • Explain global warming, its causes, and possible effects Environmental Studies, 2e

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Acid Rain • Formed when atmospheric water droplets combine with a range of man-made chemical air pollutants • Main pollutants involved are oxides of nitrogen and sulphur coming from human activities. • Automobiles and coal- and oil-fired power stations are major sources of acid-forming compounds. • Acid rain ultimately falls on the ground, sometimes hundreds of kilometres from the area in which it formed.

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Effects of Acid Rain • When soil is acidified, it leads to loss of productivity. The acidification damages plant roots. • Trees, particularly lose their leaves and die. • Acid rain falling on lakes and rivers leaves them clear and lifeless. Fish populations die and so do species like otters, amphibians, and birds that depend on fish for their food. • Acid rain harms people directly when they breathe in the acidic air. Acid rain can also harm people indirectly, when they eat fish caught in affected lakes or rivers. • Old buildings are threatened by acid rain. The Taj Mahal is affected by acid rain from by factories of Agra.

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Effect of acid rain on trees

Environmental Studies, 2e

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Environmental Studies, 2e

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Environmental Studies, 2e

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Ozone Layer Depletion • • •

• •

Ozone is a poisonous gas extremely rare in the atmosphere, The ozone layer absorbs most of the harmful ultraviolet-B (UV-B) radiation from the sun. It also completely screens out the deadly UV-C radiation. Depleting the ozone layer allows more UV-B to reach the earth. The result would be an increase in skin cancers, eye cataracts, weakened immune systems, reduced plant yields, damage to ocean ecosystems and reduced fishing yields, and adverse effects on animals. When CFCs (used as refrigerants and aerosol propellants) break apart in the atmosphere and release chlorine atoms, they cause ozone depletion. Area of the ozone hole over the Antarctic reached a record 29 million sq. km. in 2000.

Environmental Studies, 2e

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Environmental Studies, 2e

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International Initiatives against the Depletion of the Ozone Layer • Vienna Convention for the Protection of the Ozone Layer (1985): Encouraged intergovernmental cooperation on research, systematic observation of the ozone layer, monitoring of CFC production, and the exchange of information. • Montreal Protocol on Substances that Deplete the Ozone Layer (1987): Measures to reduce the production and consumption of a number of CFCs and other Ozone Depleting Substances (ODS)

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Results of Montreal Protocol • As of the end of 2009, the Parties to the Protocol had phased out the consumption of 98% of the chemicals. • Global ODS concentrations are decreasing. • Outside the Polar Regions the ozone layer has shown some initial signs of recovery. Global ozone levels are estimated to recover to the pre-1980 values around 2050. • Arctic ozone levels are expected to return to pre-1980 levels before 2050, while Antarctic ozone is expected to do so in 2060-2075. • As most of ODS are also greenhouse gases, the Protocol has yielded a reduction of approximately 25 billion tonnes of global greenhouse gases.

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Global Warming • Normally, carbon dioxide and other greenhouse gases let the radiation from the sun reach the earth, but prevent some of the heat from being reflected back out again • Due to the burning of fossil fuels and destruction of forests, the greenhouse gas concentration in the atmosphere has been rapidly increasing. • This abnormal increase in the concentration of these gases leads to higher temperatures and global warming. • Computer models indicate an average rise of 3 degrees C by 2100

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Effects of Global Warming • Global warming is likely to result in massive changes in climate, natural disasters, biodiversity loss, and sea level rise. • Climate change, bought about by global warming is perhaps the biggest environmental challenge faced by the world.

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The Story of Tuvalu • A chain of nine coral islands in the South Pacific with an area of 25 sq km and a population of 11,000 • Islands are made of porous fossil coral • Sea level rise, caused by global warming, eroding the coast • Big tidal waves and storms • Soon, the country will disappear, people have to move Environmental Studies, 2e

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The Story of Tuvalu

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The Story of Tuvalu “I feel sad & angry at the same time, sad that eventually we will have to move, and angry because this is not our doing, but because of doings of others who don’t care, who are looking after their own needs and not at the bigger picture” said by assistant secretary for the environment, Tuvalu. Environmental Studies, 2e

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Carbon Footprint • Measures the total greenhouse gas emissions caused directly and indirectly by a person, organisation, event, product, or country. • Carbon Footprint is measured in tonnes of carbon-dioxide equivalent (tCO2e). • The Carbon Footprint of a country does not just measure emissions that occur on its territory. It includes emissions that occur in the production of all goods and services consumed in a country. It also includes international transport (ocean freight and aviation).

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Key Points • Acid rain is formed by the emission of pollutants from human activities. Acid rain has a number of adverse effects on the environment and living beings. • The ozone layer in the atmosphere is getting depleted and an ozone hole has developed over the Antarctic • The depletion of the ozone layer has adverse effects on life. • The Montreal Protocol on Substances that Deplete the Ozone Layer has been successful in reducing the production and consumption of such substances. The ozone hole is now closing.

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Key Points • There is clear evidence that global warming is occurring due emissions from human activities. • Global warming will have serious effects on the environment and human society.

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