Student Book Page 471

Transcription

1 TR tive evidence, including predictions for temperature increases in the neighborhood of 1º 5ºC over the next century. 4. Apply Answers will vary, but in Alberta could likely include the increased use of wind power, biomass, fuel cells, and solar energy. Wind power, hydrogen fuel cells, and solar energy are all considered zeroemission sources, producing no carbon dioxide in their operation. Biomass and other carbon-fuelled fuel cells are considered lower-emission sources than those currently available. 5. Thinking Critically The Rio Declaration states that according to a nation s ability, they should do what they can to reduce greenhouse gas emissions even though there are still many scientific questions to be answered about climate change. Students answers will vary; however, they should mention that although it encourages action, it allows much interpretation by suggesting that nations can act according to their interpretation of capability and cost-effectiveness. 6. Thinking Critically The Gaia Hypothesis provides a viewpoint of Earth as a living being that must be kept healthy by remaining in balance. The hypothesis makes the interconnectedness of the systems of Earth more understandable, but it does not provide any suggestions as to how Earth s balance may be maintained. CHAPTER AT A GLANCE ANSWERS Student Book Page 471 (a) The enhanced greenhouse effect describes the additional greenhouse effect caused by human sources of greenhouse gases. These additional gases absorb and radiate additional heat in the atmosphere, increasing Earth s temperature above what it would normally be. (b) Over the past 100 years, seasonal temperatures have risen about 0.6ºC. (c) The greenhouse gases include carbon dioxide (fossil fuel combustion and cellular respiration), water vapour (evaporation), dinitrogen monoxide (burning fossil fuels at high temperatures and bacteria), methane (decomposition), ground-level ozone (solvents and combustion), and halocarbons (refrigerants). (d) The two main carbon dioxide sinks are the oceans and plant life. They absorb carbon dioxide from the atmosphere, thus preventing it from acting as a greenhouse gas by absorbing infrared radiation. (e) Humans cope with climate change by moving to areas that are warmer or colder, wetter or drier. Humans also develop other ways to cope. For example, as Alberta becomes drier, scientists work to develop crops that require less water to survive. (f) Higher temperatures could cause more rapid evaporation to drier areas. Climate change could cause melting of the polar ice caps causing sea levels to rise. Coastal flooding could follow. (g) Canada s biomes may shift to include some desert, less taiga and tundra, and expanded grassland and temperate deciduous forest. (h) Climate change can lead to raised sea levels as more melting occurs, flooding of coastal areas, increased evaporation (which will result in less fresh water inland), increased temperatures worldwide, and changes in precipitation levels (dry areas will tend to be drier, wet areas, wetter). (i) The goal of the Intergovernmental Panel on Climate Change (IPCC) is to provide solid scientific information on climate change that can be used by the world s policy makers. (j) The stance that people want to adopt in respect to greenhouse gases will depend on how certain they believe the threat to be and how much risk they are willing to assume in comparison to the cost of dealing with the problem. Although there is a significant amount of scientific data supporting the links among greenhouse gases, climate change, and potentially serious consequences, scientists are not able to predict with any great certainty the eventual outcome should we continue producing gases at our current and ever-increasing level. People who have a high tolerance for risk and who believe that scientists may be exaggerating the potential negative consequences will be more likely to wait and see. People with a low tolerance of risk or who believe any risk is worth the cost of dealing with the issue before links are proven are more likely to adopt the precautionary principle. (k) Climatologists use general circulation models, which are used to predict weather, along with data that mimic the composition of the atmosphere in the future to predict future temperatures. (l) Climate changes in the twenty-first century may include severe drought and flooding, and increased hurricanes and tornadoes. (i) Developing nations do not have the economic resources to rebuild after a devastating flood, nor to feed their people should drought kill the crops. (ii) Industrialized countries have the resources to rebuild, buy additional food, and conduct

2 Chapter 12 Climate Change and Humans MHR TR research to develop crops that will require less water to grow or that will grow in poorer soil. (m) The Gaia Hypothesis views Earth as one single organism whose complex series of systems work together to maintain the best possible physical and chemical environment for life. Prepare Your Own Summary In this section, students summarize topics in an interesting and informative manner. Some of the following information may be included in their ideas. - Riding a bicycle to school will help decrease the enhanced greenhouse effect since burning fossil fuels like gasoline produces carbon dioxide, the major greenhouse gas produced by humans. Every litre of gasoline burned creates 2.4 kg of carbon dioxide. - Greenhouse gas emissions could be reduced in any or all of the following ways: walking, riding a bicycle, taking public transit, or joining a carpool to reduce carbon dioxide emissions and nitrous oxides from vehicles; turning down the thermostat and turning off lights to reduce carbon dioxide emissions from power generation, especially in Alberta; planting trees and letting agricultural land return to its natural state to increase the size of the CO 2 sink; eating more food at the bottom of the food chain (fruits and vegetables) to reduce the methane emissions from cattle ranching; disposing of old refrigerators carefully and updating air conditioners to a safer coolant to eliminate emissions of chlorofluorocarbons; and considering alternative energy sources where possible, such as solar or wind power - Greenhouse gas emissions are most affected by human actions. Transportation represents 30.1% of all of Canada s greenhouse gas emissions. There are promising efforts in producing low-emissions or zero-emissions vehicles. Research is being undertaken into alternative power sources that do not produce greenhouse gases, or at least produce only low levels of greenhouse gases. If Alberta finds a better way to produce electricity, our emissions would be greatly reduced. Efforts to take public transit or use carpools can make a significant difference over 100 years. CFCs will perpetuate in the atmosphere for a long time to come, but laws have been passed to prevent the addition of even more CFCs to the atmosphere. Similar laws leading to the reduction in other greenhouse gases may be passed in the next decade or two. Other large sources of greenhouse gas emissions, including methane production by cattle and landfills, may be reduced or eliminated by new practices. In the case of landfills, methane may some day be trapped economically and sold as an additional (although carbon dioxide-producing) fuel source. - A computer model uses complex statistics to make educated guesses at what might happen in the future. Since there are so many possibilities as to what might happen, and the model is run over an extended period of time, climate change may be forecast, but not without leaving a margin for error. Every computer model will make different educated guesses that will result in different final outcomes. - The major variables that will have an impact on greenhouse gas emissions over the next 100 years are the global population, how much energy is consumed per capita, and the sources of energy used (how much carbon dioxide is produced for that source). - The Third Assessment Report of the IPCC summarizes climate change issues; its data supports a picture of a warming world where global average surface temperature has risen by approximately 0.6ºC in the past century. Other observations include a rise in sea level and increased heat content in the oceans, a decrease in snow and ice cover, and an increase in atmospheric temperatures over the past 40 years in the lower 8 km of the atmosphere. - The advantage of the Kyoto Protocol is that it is providing a framework that may be ratified by numerous carbon dioxide-producing nations, which will ultimately result in decreased production of carbon dioxide and provide a mechanism for developing nations to raise funds. The weaknesses of the protocol include the fact that it is not yet ratified, the U.S. has backed out of the agreement, and some of the targets seem difficult (if not impossible) to reach. CHAPTER 12 REVIEW ANSWERS Student Book Pages Understanding Key Concepts 1. Earth s average temperature increased by 0.6ºC over the last century. 2. The atmospheric concentration of CO 2 has increased due to a combination of increased emissions by both natural and human sources, and a reduction in the size of the CO 2 sink. 3. IPCC stands for Intergovernmental Panel on Climate Change. They are a group of over 2000 scientific experts from research institutions in over 70 countries who develop regular assessment reports on climate change. 4. Climate models are only as good as the data that is input. Scientists must predict what the atmosphere

3 TR will be in the future to model the future climate. They must make accurate guesses at the concentration of greenhouse gases 100 years into the future in order to make an accurate prediction. Another limitation of computer models is that any small change, especially in the near future, could have an enormous effect in the distant future. 5. The precautionary principle states that one should try to prevent, eliminate, control, or reduce the effect of any possible adverse environmental effects even though there is no scientific certainty that the potential adverse outcome will occur. 6. The Gaia Hypothesis states that Earth, including its atmosphere, is a self-regulating organism that maintains the best possible physical and chemical environment for life on Earth. Developing Skills 7. Scientific uncertainty is based on objective data on how carbon dioxide and other greenhouse gas concentrations have changed and how temperature changes have followed. Political disagreement is based on differences in viewpoint as to what is best for the nation represented and Earth as a whole. Political disagreement does not have to be based on data, but can be based on culture, society, and economics. 8. Climate projections into the next century are based on current data and computer simulations. A simulation must make many educated guesses to predict climate 100 years into the future. If any of those guesses are incorrect, the final outcome will be significantly different. The range in predictions, which is often the objection for sceptics, accounts for potentially incorrect guesses. Scientists are reluctant to make black-and-white statements that they cannot be backed by fact, allowing room for scepticism. 9. Students answers will vary, but students should remark on topics such the extent to which people are willing to change their lifestyles to maintain Earth s current climate. Are Albertans willing to give up eating beef? Driving cars? Paying more for electricity as coal use is reduced? 10. Students answers will vary. You may wish to add students answers to a class data bank. 11. Students answers will vary, but could include scientific background (how likely they are to believe statements based on scientific research that are not black and white), where people live (Albertans, for example, rely on fossil fuels and agriculture as mainstays of the economy), and lifestyle (whether these people live a lifestyle that would be affected by changes that would reduce greenhouse gas emissions). 12. For: Since the Industrial Revolution, the concentration of all naturally occurring greenhouse gases has increased (mostly due to human activities) along with the advent of additional non-naturally occurring greenhouse gases (halocarbons). The increase in these gases parallels an unprecedented increase in average global temperatures. Against: Earth is in a natural warming phase (interglacial period), and should be warming gradually. Although greenhouse gases are increasing due to human activity, the quantities produced by human activity are minute in comparison to those produced naturally. 13. Students answers will vary, but the easiest to implement actions include carpooling, public transit, and encouraging energy savings. Citizens could also be encouraged to plant trees and reduce the quantity of garbage they produce. 14. Students answers will vary, but should include some or all of the following: Effects of climate change drought in the Prairies coastal flooding sea levels rising longer summers continue to drive to work every day continue to use fossil fuels Effects of taking action continued dry periods in the Prairies maintained coastlines constant sea levels same length summers take the bus to work every day use alternative fuels that are zero emission or low emission 15. If Earth were a simple model where the only changes were of carbon dioxide concentration and temperature, the causal relationship would be likely, but in a system as complex as Earth, many other factors could be contributing to (or even responsible for) the rising temperature. Problem Solving/Applying 16. Alberta will be much drier and warmer than previously. Farmers (and scientists) would start developing crops that could grow in drier soil but over a longer growing season. Tourism in Alberta would also have to change its focus. Skiing and skating would no longer be winter activities of choice. (We might have to travel to the Yukon or Northwest Territories to ski.) Water would likely be rationed and be so expensive that instead of having a bath or shower daily, we might have only a 2 min shower once per week. Low-flow showerheads and minimal-flush toilets would be installed in all houses. We might play soccer on artificial turf outside since it would be a waste of water to keep the field green. Golf would either cost even more to play to pay for the water to keep the grass alive, or it too

4 Chapter 12 Climate Change and Humans MHR TR could be played on artificial turf. Cars might no longer be built with block heaters as the winters would not be as cold, but more people would install air conditioners in their cars and houses. 17. The global temperature increase over the last century was 0.6ºC, while the projected increase for the next century is somewhere between 1.4ºC and 5.8ºC, or two to nine times as great. 18. As Canada is a northern country, climate change would bring warmer weather and a longer growing season. Although longer summers would be welcomed by almost all Canadians, the sudden change in climate will be difficult for slow-to-adapt animal and plant species. Changes in sea and freshwater levels will flood coastlines and dry up waterways, destroying habitat and water supplies. 19. Scientists give a range of predictions when forecasting climate because their predictions, although based on enormous quantities of data, must account for small errors that cannot be accounted for today and which may have a significant effect on climate in the future. Critical Thinking 20. Peer review ensures a higher degree of integrity in scientific reporting as all claims will be first assessed by other experts in the field before being published in refered journals. 21. In the past 30 years, the most promising invention to decrease the amount of carbon dioxide entering the atmosphere is the fuel cell. Although this invention is not yet available in the mass market, the Ballard fuel cell would replace the internal combustion engine in our cars, the single largest individual greenhouse gas producer in Canada. Other technological innovations involve improving on existing designs to improve the efficiency (more energy per kilogram of CO 2 ), including better water heaters, furnaces, car engines, etc. The move to alternative energy sources (although all based on existing design) is also leading to decreased emissions. Wind power, a viable energy source in Alberta, may some day be commercially viable on a larger scale, as might geothermal energy. 22. Enhanced greenhouse effect is real Greenhouse gases absorb and reflect heat and greenhouse gases are increasing. Humans are responsible for these changes in the concentration of greenhouse gases. Enhanced greenhouse effect is false The human factor is small in comparison to the natural sources of greenhouse gases, so humans are not making a significant impact; the increase is natural. 23. Enhanced greenhouse effect is a serious problem Temperatures are increasing faster than what would be due to natural rates of increase. This is leading to environmental problems (ocean levels rising, changes in precipitation levels, melting of permafrost, glaciers, mud slides, increased severe weather). Enhanced greenhouse effect is not a serious problem Earth has the ability to cope with increasing temperatures (feedback). Animals and plants have adapted to changing climate in the past. Humans have the ability to deal with changing climate by moving and using technology to cope with the problems. Scientists are always predicting worst-case scenarios it may not be that bad. 24. The columns stating that the enhanced greenhouse effect is real and that it is a problem take responsibility for the climate change that is predicted, which leads to problem solving and emission-reduction programs. Even if the predictions are false and there is no enhanced greenhouse effect, and therefore no problem, our society will be no worse for undoing some of the damage we have done to the environment. The second columns ignore the possibility of a problem. By ignoring the possibility, humans will continue along the path they have set for themselves. If there is an enhanced greenhouse effect, and it causes problems because animals and plants can not adapt quickly and because only wealthy countries will be able to afford to cope with the change, there will be nothing in place to deal with the problem. The first columns promote using the precautionary principle and beginning to address the issue using cost-effective measures. The second columns suggest that there is nothing to worry about. This viewpoint might mean that if any of the IPCC s predictions happen, society will not be prepared to deal with the issue. 25. Canada is significantly larger than most nations, with a population that is spread out across the country. This, coupled with our cold climate, leads Canadians to produce more greenhouse gases through travel and heating. 26. The enhanced greenhouse effect is due to human sources of greenhouse gases. An increased population means more burning fossil fuels for travel, heating, and electricity, as well as increased agriculture to support the population. 27. A child born 65 years from now would most likely experience an Alberta that is much drier and warmer than the one we live in currently. Instead of skiing and ice hockey, winter activities would likely

5 TR be dry (no snow) and not nearly as cold, perhaps not supporting an outdoor rink for very long. During the summer, the drought would mean the grass would not be green because of insufficient water, or not as many trees would be supported since water would likely be rationed. We might play sports on Astroturf since the grass would not be able to survive the lack of water. The foods we eat may be different, as the crops would be modified to grow in less water. Instead of fishing or swimming, there may no longer be summer water sports because some streams and rivers will be dry. Students views on climate change will be more easily articulated and based in fact. Their opinion as to the impact of human activity on climate change may not have been swayed. However, they will now base their opinion on up-todate information as opposed to media hype. ASK AN EXPERT Student Book Pages SCIENCE BACKGROUND All television and radio stations have a weather reporter. The popularity of weather forecasts and general interest stories sparked the advent of The Weather Network in TWN is now available around the clock, seven days a week on television and online. The experts at TWN will even answer questions via . A rain gauge is simply a container that collects precipitation. It looks like a graduated cylinder, with volume markings on the side to allow the user to read off the amount of liquid precipitation. Automatic weather stations use remote sensors that measure temperature, pressure, wind speed, wind direction, and precipitation, among other conditions, and a main console that calculates and displays the data. The consoles can be connected to personal computers, which people, non-experts included, use to analyze the data. Satellite data is gathered using infrared sensors, which detect heat and cloud cover, and visible light detectors. The images produced using this data show a view of Earth from space, overlaid with temperature data in different colours TEACHING STRATEGIES David Phillips is frequently interviewed on television stations such as CTV, CBC, and TWN, particularly when there is immediate concern about severe weather. He is an enthusiastic and informative speaker, and students may benefit from watching a taped recording of one of his interviews. Have students relevant questions to the experts at TWN. Students may also benefit from viewing weather information and forecasts, as well as satellite imagery provided by Environment Canada. You can link to both web sites from: EXPLORING FURTHER David Phillips Purpose Students search the web site of the World Meteorological Organization to learn more about the role and operation of World Weather Watch and the World Climate Program. Advance Preparation WHEN TO BEGIN 1 week before Time Required min APPARATUS computer(s) with Internet access Book computers with Internet access. none WHAT TO DO MATERIALS Implementing the Activity Have students read the Ask an Expert feature before class. During class you may wish to show them a taped interview with David Phillips. Have students research and write notes to answer the questions in the Exploring Further item. You can link to the web site of the WMO via: Activity Wrap-up Discuss the questions asked in the Exploring Further item with the class.