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1 of 37© Boardworks Ltd 2006
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3 of 37© Boardworks Ltd 2006 Human impact on the environment How does human activity affect the environment?
4 of 37© Boardworks Ltd 2006 There are about 6.6 billion people in the world and over 95 million babies are born per year – that is an average of three babies per second! Population growth Has the rate of population growth always been the same?
5 of 37© Boardworks Ltd 2006 Exponential growth
6 of 37© Boardworks Ltd 2006 The human population is said to be growing exponentially. This means that the larger the population, the faster it grows. Exponential growth An increase in average life expectancy is largely responsible for the rapid increase in population. Why do people live longer than they did hundreds of years ago? better healthcare (hospitals, medicines, vaccines) more and better food cleaner water better sanitation The biggest increase in population is in developing nations, rather than developed nations. Why do you think is the case?
7 of 37© Boardworks Ltd 2006 Computer models can be used to make predictions about population growth by using assumptions about birth rate. Predicting future growth rate Most analysts assume that birth rates will fall within the next 50 years. Why do you think this might happen? How important do you think predictions about climate change and unsustainable development are in the analysts’ calculations? decreased fertility lack of resources disease war
8 of 37© Boardworks Ltd 2006 Future population growth
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10 of 37© Boardworks Ltd 2006 Air pollution Human activity produces two main types of air pollutant: particulates – These are tiny particles suspended in air (e.g. smoke) and which are usually produced by the combustion of fossil fuels. noxious gases – These include carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ). Air pollution has been a major problem since the Industrial Revolution of the late 18 th Century, and has been made worse by humans’ reliance on burning fossil fuels for energy. Air pollution, global warming, acid rain, damage to the ozone layer and smog. Each of these has serious implications for the environment and human health.
11 of 37© Boardworks Ltd 2006 Global warming and greenhouse gases One of the greatest threats caused by air pollution is global warming. Global warming is caused by a build-up of greenhouses gases, which leads to an increase in the Earth’s temperature. A greenhouse gas is an atmospheric gas that absorbs infrared light. Key greenhouses gases include: carbon dioxide (CO 2 ) methane (CH 4 ) water vapour (H 2 O) nitrous oxide (N 2 O)
12 of 37© Boardworks Ltd 2006 The greenhouse effect
13 of 37© Boardworks Ltd 2006 Acid rain
14 of 37© Boardworks Ltd 2006 What damages the ozone layer? CFCs are used in fridges and freezers, aerosol sprays and packaging materials such as polystyrene. The production and use of CFCs is now banned in many countries and could be worldwide in a few years. The ozone layer is a protective part of the atmosphere that absorbs some of the Sun’s damaging ultraviolet (UV) rays. Damage to the ozone layer means that more UV rays reach Earth, increasing the risk of skin cancer. The ozone layer is damaged by chemicals called chlorofluorocarbons (CFCs), which contain the elements carbon, hydrogen, chlorine and fluorine.
15 of 37© Boardworks Ltd 2006 What is smog? Smog is a mixture of air pollutants and particulates that is sometimes found in the lower levels of the atmosphere. It has a distinctive brownish haze. A large part of smog is ground-level ozone, a highly toxic gas. Smog can reach dangerous levels in built- up areas, causing irritation to the eyes and lungs. Ozone is formed when nitrogen oxides and hydrocarbons react with oxygen, in a reaction catalyzed by sunlight.
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17 of 37© Boardworks Ltd 2006 Water pollution Fertilizers and sewage can easily be washed into rivers, streams and lakes. The nutrients, phosphates and nitrates in these substances cause eutrophication. Sewage, industrial waste, oil, pesticides and fertilizers all pollute water. Eutrophication is the accumulation of nutrients in water, which causes excessive algal growth. This leads to a reduction in oxygen levels and the death of aquatic life.
18 of 37© Boardworks Ltd 2006 Eutrophication
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20 of 37© Boardworks Ltd 2006 Land pollution Land and soil can be polluted by two main types of substance: solid waste – such as plastic, metal, paper and other man- made substances chemicals – such as herbicides and pesticides, crude oil and waste from industrial processes. Land pollution often leads to water pollution, as chemicals are washed into rivers and lakes.
21 of 37© Boardworks Ltd 2006 How much waste? Every year, billions of tonnes of paper, plastics, synthetic materials, metal and wood are thrown away. On average, each UK household produces over 1 tonne of rubbish each year. How could you estimate the amount of rubbish you throw away each year?
22 of 37© Boardworks Ltd 2006 What is the best solution? The best way to deal with waste is to produce less of it! If products were redesigned to be biodegradable or easier to recycle, the amount of waste and disposal costs would be significantly reduced. How could you reduce the amount of waste you produce? It takes 100 kg of resources to make 10 kg of shopping, and most of that ends up in the bin.
23 of 37© Boardworks Ltd 2006 Recycling rates
Air Pollution. Whats in the Air? Nitrogen, oxygen, carbon dioxide, water vapor, and other gases Air pollution –Solid particles and gases that are released.
Human Impact on Air Resources
Boardworks GCSE Science: Biology Human Impact on the Environment
Air is an important natural resource.
CHAPTER 54 ECOSYSTEMS Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section E: Human Impact on Ecosystems and the Biosphere.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. MICHAEL D. JOHNSON HUMAN IMPACTS, BIODIVERSITY, AND ENVIRONMENTAL ISSUES CHAPTER.
ECOSYSTEMS & HUMAN INTERFERENCES II. Carbonification The destruction of vegetation & burning of fossils are main factors in increasing carbon in the.
1 THE EFFECTS OF THE POPULATION EXPLOSION p. 264.
Earth Science 4.3 Water, Air, Land Resources
B-6.6: Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and.
3 Air pollution p.268. Objectives Students should learn: that air can be polluted with smoke and gases, such as sulfur dioxide, which contributes to acid.
Chapter 5 Vocabulary air pollution emissions photochemical smog ozone acid rain ozone layer chlorofluorocarbons (CFCs) greenhouse effect global warming.
AND SOLUTIONS! Environmental Issues. The environment is all connected! (p.87) Environmental issues fall into three general categories: 1. Human population.
Biology 1b Evolution and Environment GCSE CORE Key words: non-renewable, pollution, waste, indicators.
Human Effects on the Atmosphere
2 Land and water pollution p.266. Objectives Students should learn: that more waste is being produced which may pollute water with sewage, fertilisers.
Aim: How is the earth's atmosphere similar to a greenhouse?
What do you think this means?. Learning Targets 8. Identify the causes and effects of pollution on Earth’s cycles. 9. Explain how pollution affects.
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