Climate Change
What factors affect climate change?
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The earth has many different types of climates and it is these climates that affect diversity
Weather – is a set of physical conditions of the lower atmosphere (precipitation, humidity, temperature, wind,
cloud cover, etc.) over a set of hours or days
Climate – is the area’s general pattern of atmospheric conditions over a long period of time. Basically it is
weather over a long period of time
Major factors affecting climate
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Global air circulation
α Affected by uneven heating of the earth’s atmosphere by the sun
α Rotation of the earth on its axis
α Convection cells of water from land to the atmosphere and back again
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Ocean currents
α Affected by winds
α Cold and hot ocean currents
Local climates – affected by topographical features:
o Mountains – create rain shadow affect
 Leeward side creates a desert and the windward side is a high amount of moisture
o Cities
 Bricks, concrete, asphalt absorb and hold heat while the buildings block wind. As well there is a
large amount of pollutants being created in a small area. All of these factors create haze, smog
and a higher temperature.
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The Earth’s Atmosphere
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Pressure in the atmosphere decreases with altitude, and this decrease is more rapid at lower altitudes than at
higher altitudes. As a result, the majority of the mass of the atmosphere (about 99%) lies within 30km of Earth’s
surface.
The atmosphere is divided into five regions based on temperature changes: the troposphere, stratosphere,
mesosphere, thermosphere, and exosphere. In terms of composition, Earth’s atmosphere is typically divided
into 2 regions: the homosphere and the heterosphere.
o The Homosphere
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Gases are fairly evenly blended, giving the region a fairly uniform composition. The uniformity results from
mixing of the gases by convection – a cyclical movement of air molecules caused by difference in air density.
o The Heterosphere
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There is no mixing of gases in the atmosphere by convection. Therefore the gas composition in the heterosphere
varies and is limited to a few types of gases, and they are layered by their mass.
Ecosystem Services
Ecosystem services are the benefits that organisms (including humans) receive from the environment and its resources.
Ecosystem services are the natural result of all the activities that take place in the biosphere. Keep in mind that services
are inseparably linked together on a global scale. Each is as important as any other, and none is expendable or
replaceable.
Ecosystem Service
Atmosphere gas supply
Climate regulation
Disturbance regulation
Food production
Genetic resources
Habitat (living spaces)
Nutrient cycling
Pollination
Raw materials ( natural resources)
Recreation
Soil erosion control
Water regulation
Water supply
Waste treatment
Examples of Ecosystems Services
Example
Regulation of carbon dioxide, ozone, and oxygen
Regulation of greenhouse gases
Storm protection, flood control, drought recovery, and other
aspects of environmental response to disturbances
Crops, livestock, fish
Medicines, genes for disease resistance
Habitat for migratory species and for locally harvested species,
overwintering grounds, nurseries
Carbon, nitrogen, and other nutrient cycles
Pollination of crops such as apples, blueberries, and clover
Fossil fuels, timber, minerals
Ecotourism, sport fishing, hiking, and other outdoor activities
Retention of topsoil
Supplying of water for agricultural (such as irrigation) and
industrial (such as milling) processes
Supplying of water by reservoirs, watersheds, and wells
Sewage treatment
Carrying Capacity, Ecological Footprint, and Sustainability
No population can keep growing indefinitely. The largest size of a population an environment can support is the carrying
capacity of that environment for that species. Carrying capacity is determined by factors that include food and energy
supply, oxygen supply, living space, disease, predators and competitors.
One way to increase carrying capacity of a specific environment for a specific population is to alter that environment so
that more energy and resources can be consumed. Another way involves changing the behavior of the population. An
ecological footprint is a measure of the impact of a population (of an individual) on its environment. Data used to
measure an ecological footprint include energy consumption, land use, and waste generation. A population’s footprint
reflects the collective behaviors of its individual members. It describes the amount of productive land and water needed
to support a population’s (or individual’s) standard of living.
The average person in developed countries such as Canada has one of the largest ecological footprints in the world.
Footprints this large on a plant that has finite resources is likely to be unstainable. A growing world population puts
more stress on ecosystem services. As the footprints of people in developing countries also increases in size, these
stresses will become greater. Thus, modern societies are now trying to establish footprints that reflect the concept of
sustainability – using Earth’s services in ways and at level that can continue forever. Another aspect of sustainability is
the idea of keeping natural resources and ecosystem healthy over time and maintaining human living standards in
balance with economic growth. Thus, discussions of sustainability often take these 3-dimensions – the environment,
society, and economics – into account.