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Resources. Fresh Water. Important facts: Only 3% of the world’s water is fresh water. 18% of the world’s surface fresh water is in the Great Lakes. Most fresh water is either frozen or underground. Why are we worried about water supply?. Water Supply.
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Fresh Water • Important facts: • Only 3% of the world’s water is fresh water. • 18% of the world’s surface fresh water is in the Great Lakes. • Most fresh water is either frozen or underground.
Water Supply • The world’s population is constantly growing. • Each person needs at least 5 liters of water per day. • In developed countries, most people use over 200 liters per day! • Result: Groundwater and surface water resources are dwindling.
The problem of population growth • The more people our planet has, the more food we need to grow. • Result: More water is used to irrigate land for farming. • Result: Water tables are falling all over the world.
Why is depleting groundwater resources dangerous? • Farmers will have to rely in seasonal rains - farms will yield fewer crops. • Poor countries with growing populations will depend on imports of food for survival. • The land above the water table may subside as the water table falls. This is the reason why New Orleans was completely flooded for weeks after it was hit by Hurricane Katrina.
Can the depletion of ground water lead to a world wide famine?
Threats to surface water • Surface water will always be present as it is renewed all the time by the water cycle. • However, the amount of surface water we can safely use is decreasing as a result of: • Pollution
How is surface water polluted? • Municipal waste (sewage, detergents, solvents, garbage) • Agricultural waste (herbicides, pesticides, fertilizers) • Industrial waste (chemicals, oil, waste)
Canada’s Role • Victoria and Halifax dump untreated sewage into the oceans. • Pulp mills provide 50% of industrial waste in the Fraser River. • The Fraser Valley and Vancouver dump 90% of the municipal waste found in the river.
Consequences • Fish, such as sturgeon, in the Fraser River are becoming endangered. • In the St. Lawrence River, Beluga whales are declining in numbers. • Algae and weeds are growing more often, depleting the water’s oxygen and creating dead zones. • In the Okanagan region, milfoil weed is threatening to destroy all other life present in lakes.
Solutions • conservation • more efficient rain-water harvesting • recycled water • desalinated water • drip irrigation • more efficient use at home (low flow toilets) • taxes on water use • national policy to control use
What is the Ozone Layer and why is it important? • It is a thin layer or ozone (O3) in the earth’s upper atmosphere. • Ozone blocks the sun’s ultraviolet (UV) rays and stops them from reaching the surface of the earth. • This is important because UV radiation causes skin cancer in humans and kills other organisms such as plankton on the surface of oceans
What causes the Ozone Layer to Deplete? • Chemicals used by humans, especially CFC’s (Clorofluorocarbons) which are found in coolants, foam, and aerosol sprays. • Because of the wide spread use of these chemicals, by the 1980s the Ozone Layer had developed holes over the North and South Poles.
Result • In 1987, all industrial countries met in Montreal. • Here, they signed an agreement called the Montreal Protocol. • They agreed to cut their use of CFCs and to allow the developing countries to use CFCs only until the year 2000. • Today, scientists believe that the Ozone layer might be slowly repairing itself.
Why is the earth heating up? • Since the Industrial Revolution, humans have been burning massive amounts of fossil fuels (coal, oil, natural gas). • When fossil fuels are burned, they release Carbon Dioxide (CO2) into the atmosphere. • CO2 traps the sun’s heat in the atmosphere and does not allow it to escape. • Result: The earth is getting warmer.
Why is global warming dangerous? • increased heat waves and droughts • increasing number of violent storms • melting glaciers and ice caps in polar regions • rising sea levels • diseases have extended ranges • shifting plant and animal ranges • extinction of life forms that fail to adapt
Effects of Global Warming on Canada • Polar bears may become extinct • Many people will be displaced from their homes • Other species, like salmon, may become extinct due to the increasing temperature of the water • Winter recreation areas may suffer due to lack of snow • Violent storms will be more likely • Hotter, conditions will make forest fires and brush fires more common and more dangerous • Increasingly dry conditions in the Prairies will make farming more difficult.
Effects of Global Warming on Canada • Permafrost will melt – man-made structures will sink and be damaged. • Pests will be able to survive farther north and south of the equator – this will put our forests in danger (pine beetle). • Coral reefs will die as they will be unable to handle the temperature shift. • Tiny island nations (Maldives, Tuvalu) will disappear. • Farmland will be flooded.
Effects of Global Warming on Canada • Species will migrate as the climate of their habitat becomes more inhospitable to them – this may have a huge impact on food chains. • Increasingly dry conditions in South America will lead to the demise of the Amazon rainforest. • Human diseases such as malaria will have extended ranges. • Ocean currents may be disrupted, causing enormous climatic changes all over the globe.
What is being done about it? • In 1997, Canada was one of many countries that signed the Kyoto Protocol. • All these countries promised to reduce their greenhouse gas emissions to 6% less than their 1990 levels by the year 2012. • The USA has not signed this agreement. • Recently, the Canadian government said that we would not be keeping our promise either.
Why is so little being done to stop Global Warming? • The fossil fuel industry is lobbying against this. • Many people believe it would be too expensive to try and cut greenhouse gas emissions quickly. • The world population keeps growing, and everyone wants to have the same lifestyle as people in developed countries. • This would be a disaster, as people in Canada produce 40 times more pollution that people in developing countries.
Other Solutions • Alternative sources of power • wind, solar, hydro, geothermal, hydrogen, nuclear • Less use of automobiles • New sources of fuel for cars (hydrogen, hybrid,…) • Energy conservation
Disappearing Resources Are we running out of time?
Agriculture and Soil Soil is one of the most important primary resources for all living things. • It provides a means of survival for almost all plant and animal species.
Why do we need to worry about soil? • Soil takes hundreds of years to form. • Soil erosion (removal of soil) by wind or water is very fast. • Humans are speeding up the process of soil erosion.
So how are humans destroying the soil? • Over farming • Use of chemicals • Deforestation
Over Farming • In most places where farming takes place, people try to get as much profit as possible from as little land as possible. • In order to achieve this they: • Farm the land every year, usually with the same crop. • This depletes the nutrients from the soil - the crops that use the nutrients are removed, and the nutrients are not replaced. • Result: The soil is left completely dried out – the amount of food that can be grown on it is reduced, and it can be easily blown away by wind, or carried away by water.
Use of Chemicals in Farming • In order to deal with the depleted fertility of the soil, farmers are usually forced to use chemicals. • In the long run, this has many negative consequences: • The most commonly used chemicals are pesticides and herbicides. These kill the pests / weeds that compete with the crops for nutrients. • Chemical fertilizers are also used to provide food for plants when the natural fertility of the soil is too low. • Consequences: • Chemicals seep into ground water and streams. • Many of plants and animals, as well as the people who come into contact with these chemicals, are harmed by this. • The chemicals make the soil sterile, so that only one type of plant can survive.
Deforestation • While forests in northern countries such as Canada are no longer being depleted, the more important tropical rainforests are being destroyed at a rapid pace! • Why are tropical rainforests important? • Biodiversity – they contain millions of species of plants and animals. • They absorb carbon dioxide and give off oxygen (they reduce global warming).
The Amazon Rainforest This is the world’s largest tropical rainforest. It is located in South America.
The Amazon Rainforest • This forest is being destroyed because • Poor people are clearing it to make way for farms and ranches. • Once it is cleared, the soil quickly becomes infertile and the farmers / ranchers must clear new land within a few years. • Trees are also cut down because their wood can be sold. • Roads have also been built through the forest to provide access to oil and mineral reserves.
Consequences of Deforestation • Desertification • Soil erosion • Silting of lakes and rivers • Floods • Climate change (local and global) • Drought
