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Climate Change. http://www.youtube.com/watch?v=V1VYmpTikgw&feature=related. Temperature trends. We’ve seen a lot of record-breaking temperatures in the past decade. The average temperature across the world has risen by 0.76°C since 1880 (when detailed temperature data was first recorded).
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Temperature trends • We’ve seen a lot of record-breaking temperatures in the past decade. The average temperature across the world has risen by 0.76°C since 1880 (when detailed temperature data was first recorded).
Leading causes • Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions. • CO2 – this is a by-product of fossil fuel combustion (oil, natural gas and coal). • CH4 – produced mostly by livestock (during digestion) and by manure management. • N2O – produced from industrial activity and fertilizer use.
How it works • Greenhouse effect • http://videos.howstuffworks.com/howstuffworks/2261-how-greenhouse-gases-work-video.htm
The Future • According to predictions, average earth temperatures could rise by 3°C to 5°C by 2100. • This could have disastrous meteorological, geographical, and biological effects.
Impact of climate change • Melting ice in the north: • We have an enormous amount of water trapped in the form of ice in the polar ice caps. • Melting the ice caps could raise the sea level by several feet. • Florida would be submerged.
Impact of climate change • The threat of malaria: • Malaria is a parasite transmitted by mosquitoes. It infects humans and destroys our liver. • The parasite can only tolerate specific temperatures. With increasing temperatures across the world, the parasite could spread.
Impact of climate change • Drought-stricken farms: • Higher temperatures lead to higher rates of evaporation. • Less water for farmers growing our foods.
More impacts • http://www.youtube.com/watch?v=lnVGzlXmgko
Global solution • United Nations Framework Convention on Climate Change (1992, Brazil) 154 countries and the EU decided they needed to take action. • Five years later during their 3rd meeting, taken place in Kyoto , Japan, they signed the Kyoto Protocol. • The countries agreed to lower their greenhouse gas emissions to levels 5% below their 1990 levels. These levels were to be measured in about 10-15 years (2012). • Canada’s emissions are still on the rise.
Review • What’s the average global increase in temperature since 1880? • What are the three leading causes of the greenhouse effect? • Concerning the impact of climate change, what were the three repercussions discussed? • An agreement was signed by several countries pledging a decrease in greenhouse gas emissions. What was the agreement called?
Drinking Water • We need 1.5L/day to live. Just 4 days without water and we die. It’s very important. • Despite covering 2/3 of the world’s surface, only 2.5% of this water is fit for human consumption. The rest is too salty. • Unfortunately, most of this 2.5% is inaccessible: trapped in glaciers and underground aquifers.
Water quality • There are several criteria which are examined in order to ensure the quality of our drinking water: • Sensory properties: colour, clarity, odour, taste. • Physical and chemical properties: pH and salinity. • Toxic substances: heavy metals, pesticides. • Microbiological parameters: bacteria, viruses, fungi. Unfortunately, every year contaminated water claims five million lives.
Threats to the water supply • Pollution: most common pollutants include: • pesticides and fertilizers used on farmlands • heavy metals discharged from in wastewater from factories • bacteria from sewage water. • Climate change itself: rising temperatures cause increasing evaporation. • This could lower the level of the St. Lawrence. Water from the Gulf would come in increasing the salinity of the water, making it unfit for consumption.
Excessive human consumption • In homes, individual Canadians use an average of 335L of water per day. • This is an average over the year: includes filling swimming pools, car washes, and lawn watering.
Smart homes • http://news.discovery.com/videos/tech-smart-tech-measures-personal-water-consumption.html
Review questions • What are the criterion used verify the quality of our water? • What percent of the world’s water is drinkable? • What are some of the threats to our water supply?
Deforestation • Forests are important for a variety of reasons. • They’re home to a large proportion of plants and animals. • They capture carbon dioxide. • Prevent soil erosion (loss of soil due to floods or wind). • Reduce risks of natural disasters (floods, avalanches, and desertification). Net change in forest area, 2005-2010 (ha/year)
Causes of receding forests • Clearing land for farming. • In some areas, forests are cleared by fire and crops are planted until the soil is no longer fertile. • Logging. • Harvesting forests for the pulp-and-paper or lumber industries. • Monoculture. • A practice which involves planting one type of crop or species of tree. These are more vulnerable to disease and insects because of reduced biodiversity. • Also causes soil depletion as the monocultures draws constantly on the same nutrients.
Causes of receding forests 4. Urbanization. • As populations grow, the need for more space will increase. 5. Air pollution. • Fossil fuel combustion releases pollutants into the air. • Sulphur dioxide (SO2) and nitrogen oxides (NOx) contribute to ACID RAIN. • Soil exposed to acid rain cannot retain its nutrients. 6. Natural factors. • Fires, landslides, or diseases caused by insects.
Impact of deforestation • On biodiversity: • Forests harbour ~70% of living species, including birds, insects, plants, fungi and microorganisms. • On the water cycle: • Trees reduce surface runoff, as they absorb much water. • Trees reduce soil erosion. • Trees release water into the air through evapotranspiration (maintains air humidity). • On the climate: • When cut, the carbon in the trees is released as CO2 as the trees decompose. This is responsible for much greenhouse gas emission. • By acting as windbreaks and maintaining air humidity, trees help regulate temperatures in certain areas (think of drier areas like deserts).
Deforestion • http://www.guardian.co.uk/environment/video/2010/sep/28/deforestation-paraguay • In Barbados: http://www.youtube.com/watch?v=AOjRnqRSCO8
Main stages of the water cycle • Evaporation • Condensation • Water storage in the atmosphere • Precipitation • And repeat…
We can damage certain parts of the water cycle… • Hotter weather more evaporation but less condensation. • Clearing trees less humidity and less evapotranspiration. • Less plants and trees less water absorbed from the soil, more remains trapped in the earth.
Review questions… • Why are forests so important? • What is causing them to recede? • Is the loss of forest a bad thing? And why?
Effect of greenhouse gases • Warming climate: sunlight going through the atmosphere heats up the earth’s surface. The greenhouse gases in the atmosphere prevent the heat from being lost. Analogy: the interior of a car on a sunny day. • Also, we get the depletion our ozone layer because of halocarbon compounds we use as refrigerants: CFCs, freon, etc. • The ozone layer is a layer of O3 that protects us from the electromagnetic radiation of the sun.
Energy • Consumption: • North Americans have a very unhealthy appetite for luxury items requiring enormous amounts of energy to make, i.e. the automobile. • The automobile has helped urbanization become a reality because people can live farther from where they work.
Classical sources of energy • Problems with these energy sources: greenhouse gases are emitted and they’re not renewable. • Sources: • Wood: in some parts of the world, people use wood for cooking and heating purposes. • This can lead to desertification due to deforestation. • Coal: This was a popular means of producing electricity in Canada up until the 20th century. • Burning coal releases SO2 and NOx causing acid rain. • Also, produces mercury emissions which returns to earth in the rain. This is absorbed by fish, which are consumed by humans.
Classical sources of energy 3. Oil: this is unearthed from deep wells in the earth. Oil is refined into all sorts of products, like gasoline. • Burning oil also generates gases responsible for acid rain. • Its combustion isn’t the only process that is harmful: it’s extraction from tar sands and transportation are also very polluting.
Classical sources of energy 4. Natural gas: these are combustible gases which burn cleaner than oil or coal. Mainly composed of methane (CH4). We also find ethane (C2H6) as well. • We use it to heat homes and generate electricity. 5. Nuclear: When a uranium atom breaks apart, it releases a lot of energy in the form of heat. This spins turbines to generate electricity. • No greenhouse gas emissions, but you’re left with nuclear waste.
Renewable energy • Hydroelectricity using water from rivers to spin turbines. • Wind power largest ones can generate enough power to supply 200-300 homes with electricity. • Solar energy photovoltaic (solar) panels generate a current when they’re hit with sunlight. • Geothermal energy capturing heat from inside the earth to generate electricity. • Tidal power using the movement of water in tides to spin turbines.
Reducing consumption • Minor changes: turning off lights or heating and using energy-efficient light bulbs. • Major changes: • Energy-efficient cars • Energy-efficient industries (released water vapour can heat building in winter) • Energy-efficient homes
Renewable energy • http://www.youtube.com/watch?v=NQKafeKMJIQ
Review • So what types of classical energy sources exist? • What types of renewable energy sources exist? • Are there common problems between the two? • Ultimately, what can we do to reduce our carbon footprint?
Food production • In order to keep up with the high food demand, we’ve had to revolutionize our agricultural practices. • This includes the use of machinery in growing and collecting food. • The main idea is mass production.
Problems with mass production • Soil compaction: heavy machinery compacts the earth. This reduces arable land because the land doesn’t absorb water as easily. • Soil depletion: intense farming doesn’t give soil time to renew its supply of nutrients. • Fertilizers: chemicals can runoff into water supply. • Pesticides: can be very harmful to humans over time.
Global food crisis • Rising food prices all over the world: • http://www.youtube.com/watch?v=3qzKUZ-FUUw&feature=related
GMO • Genetically-modified foods.