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81 Cards in this Set
- Front
- Back
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What is climate?
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The average conditions of the atmosphere in a large region over 30 years or more
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What characteristics are included in climate?
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clouds, precipitation, average temperature, humidity, atmospheric pressure, solar radiation and wind
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Why does British Columbia have a range of climates?
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varied geography
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What is a biogeoclimatic zone?
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a region with a certain type of plant life, soil, geography and climate
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What characteristics are used to determine the type of biogeoclimatic zone?
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plant life, soil, geography and climate
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How many biogeoclimatic zones does British Columbia have?
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14
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What are paleoclimatologists?
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people who study climates of the geological past
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How do paleoclimatologists gather evidence on ancient weather patterns?
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- study plant fossils
- look at tree trunk rings - examine sediment layers - examine ice cores |
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What do fossils show?
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what kind of environment was present
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What do tree rings show?
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good growing years
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What do river sediments show?
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types of rainfall
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What do glacier ice cores show?
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- air condition and composition for thousands of years
- gases trapped in the ice (carbon dioxide) reveal long term atmospheric gas levels |
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What is an ice core?
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cylinders of ice drilled from thick glaciers to determine the types and amounts of gases that existed in the atmosphere when the ice formed
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How does evidence show that Earth's climate has drastically changed often in the past?
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- fossils and sediment evidence show dramatic climate changes in the past
- 21 000 years ago much of Canada and Northern Europe was under glaciers - ice core data reveals carbon dioxide levels for the past 650 000 years |
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Name factors that can cause dramatic climate changes
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- composition of the Earth's atmosphere
- Earth's tilt, rotation, and orbit around the Sun - the water cycle - ocean currents - the carbon cycle - catastrophic events |
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Why is Earth considered a closed system?
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- a group of parts that function together as a whole
- very little energy enters of leaves the system (except the Sun) - Earth's atmosphere is the outer boundary |
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What is a greenhouse?
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a closed system that traps thermal energy
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What is the natural greenhouse effect?
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absorption of thermal energy by the atmosphere
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What are greenhouse gases?
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gases in Earth's atmosphere that absorb and trap radiation as thermal energy
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What would happen to Earth's temperature had greenhouse gases not existed?
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the global temperature would be 34 degrees lower
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What three characteristics of earth's movement affect the global climate system?
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Earth's tilt, rotation and orbit
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Why does Earth experience seasons?
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due to the combination of its tilt and yearly orbit around the Sun
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Describe Earth's tilt in both summer and winter
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Summer - tilted toward the Sun decreasing the angle of incidence
Winter - tilted away from the Sun; solar radiation has a large angle of incidence |
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What is the range for Earth's tilt?
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22.3 degrees and 24.5 degrees (we currently are at 23.5 degrees)
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What would happen if Earth had no tilt?
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seasonal changes at higher latitudes would be less noticeable
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What would happen when Earth's tilt is at it's greatest?
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the seasonal changes would be extreme
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What causes the change in Earth's axis rotation?
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Earth's "wobble"
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What is Earth's "wobble"?
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where the North pole of Earth points to a star called Polaris but in 12 000 years, it will point to a star called Vega
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What happens when Earth's axis changes in the 23 000 year cycle?
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the angle of incidence of solar radiation also changes this way
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What happens to Earth's orbit in the 100 000 year cycle?
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orbit becomes more circular (currently is elliptical)
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What happens when the orbit of Earth is the most elliptical?
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they will receive less solar radiation when it is further away from the Sun as usual
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What do tilt, rotation and "wobble" affect?
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climate
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What is the water cycle?
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the circulation of water on, above and below Earth's surface
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What is the most abundant greenhouse gas?
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water vapour
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Name two effects if there was more water vapor in the atmosphere
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- more solar energy can be trapped by this greenhouse gas
- more solar energy can be reflected back out into space and never reach Earth |
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What happens in terms of the water cycle when surface temperatures rise?
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increase in water evaporation and capacity of air to hold water vapour
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Describe convection currents in the ocean
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large amounts of thermal energy are moved all around the Earth
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What are deep ocean currents?
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- 500m and deeper
- flow is based on density difference - behave like massive convection currents with warm water rising in the tropics and cold water from the higher latitudes replacing it - deep ocean currents move cold, salty water below and warm less salty water near the surface |
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What happens to the glaciers as a result of the warming climate?
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Glacier melting could add large amounts of salt-free water to the oceans
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How does salinity affect the density of water?
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Cold water - (found at the poles) is denser than warm water
Salty water - is denser than less salty water |
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What happens when there are large changes in ocean water density?
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the current direction can be reversed
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What influences the path of surface currents?
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wind, Earth's rotation (Coriolis effect) + shapes of continents' coastlines
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What are surface currents?
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Currents that are 0 - 500m deep and warm from solar radiation
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What is the thermocline?
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the transition zone between warm surface waters and cold, deep ocean waters
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What happens when upwellings occur?
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cold, deep water rises above the thermocline into surface currents
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What is La Nina?
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cooler than normal water coming to the surface in the Eastern Pacific Ocean due to upwelling; as a result, winter temperatures are unusually warm in Southeastern North America and unusually cold in the Northwest
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What is El Nino?
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an unusually warm ocean current that develops periodically off the coast of Ecuador and Peru, often producing unusually mild weather along the coast of British Columbia and in Eastern Canada
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What would happen if there were no carbon dioxide molecules?
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infrared radiation would not get trapped resulting in the average temperature of Earth dropping below freezing
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How does the carbon cycle maintain a balance of carbon dioxide in the atmosphere?
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- deep oceans and forested areas are carbon sinks
- carbon dioxide in the ocean is converted to bicarbonates in shells of marine animals - phytoplankton use carbon dioxide for photosynthesis near the ocean's surface - weathering of rocks releases carbon - carbonic acid is formed when water reacts with carbon dioxide in the air - forests take in carbon dioxide via photosynthesis but release carbon dioxide when burned or decaying |
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What is a carbon sink?
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a body or process that removes carbon dioxide from the atmosphere and stores it
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What is a carbon source?
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a body or process that releases carbon dioxide into the atmosphere
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What is weathering?
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the process in which rock is broken down into smaller fragments
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What is a catastrophic event?
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large-scale disasters
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What happens when volcanic eruptions occur?
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- ash and molten rock that absorb radiation are released
- water vapour and sulphuric acid can reflect solar radiation back into space |
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What happens when meteorites strike Earth?
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- releases large quantities of dust, debris and gases in the atmosphere
- solar radiation is affected so much, it is thought that these events are responsible for some of Earth's largest extinction events - large comets and meteor collisions with Earth can cause debris to block solar radiation and change the entire planet's climates |
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What is climate change?
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the change in long-term weather patterns in certain regions
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What does climate change affect?
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the flow of thermal energy over the entire Earth
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What is global warming?
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the increase in global average temperature
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What is the "Enhanced Greenhouse Effect"?
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the increased capacity of the atmosphere to absorb and emit thermal energy due to an increase in greenhouse gases
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What are the greenhouse gases?
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- water vapour
- carbon dioxide - methane - nitrous oxide - CFC's and perfluoromethane |
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What is the global warming potential?
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the ability of a substance to absorb and emit thermal energy
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Name the GWP's of carbon dioxide, methane, nitrous oxide and CFC's
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carbon= 1
methane= 25 nitrous oxide= 298 perfluoromethane= 6500-9200 |
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Name sources from human activity for several greenhouse gases
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carbon dioxide= deforestation
methane= waste dumps nitrous oxide= industrial processes chlorofluorocarbons= air conditioning |
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What caused carbon dioxide levels to greatly increase in the past 200 years?
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1. The Industrial Revolution - increased the use of fossil fuels
2. Deforestation has changed carbon sinks into carbon sources |
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How do people attempt to reduce carbon dioxide emissions?
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- using/purchasing energy from alternative energy sources
- reducing their energy consumption - planting more trees to remove carbon dioxide from the atmosphere |
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How is methane produced?
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- bacteria breaking down wastes in oxygen-free environments
- garbage decomposing in landfills - animal digestion - plant matter, rice paddies - extracting, producing and burning fossil fuels |
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Where does nitrous oxide come from?
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- bacteria
- nitrogen-rich chemical fertilizers - improper disposal of human and animal waste - car exhaust |
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What is the ozone?
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- an important UV radiation blocker in the stratosphere
- a very powerful greenhouse gas at lower altitudes, close to Earth's surface, where it naturally occurs in trace amounts |
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What does the ozone result from?
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chemical reactions between solar radiation and pollution from the burning of fossil fuels
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What are CFC's?
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- most powerful greenhouse gases
- Montreal Protocol - a treaty designed to protect the ozone layer by phasing out substances considered to be responsible for the depletion of the ozone layer - Cl atoms break apart ozone molecules - they are found in coolants, aerosols and fire extinguishers |
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How does albedo affect climate?
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- albedo at Earth's surface affects the amount of solar radiation that a region receives
- if changes occur in a region's albedo, climate changes could follow |
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Describe relationship between forests and albedo
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- forests provide a low albedo
- deforestation increases the albedo because the region reflects more solar radiation |
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Describe relationship between arctic ice and albedo
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- arctic ice has a high albedo
- melting of large areas of ice decreases albedo because region absorbs more solar radiation |
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How is the role of science used in understanding climate change?
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- measurements must be taken from around the world over a period of time in order to identify trends in climate change
- scientists use computers to model what Earth's climate might be like - General Circulation Models (GCM's) are computer models used to study climate |
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How are GCM's used to understand climate change?
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- used to predict future climatic conditions and have also reproduced climates of the past
- take into account changes in greenhouse gases, albedo, ocean currents, winds and surface temperatures - used for weather forecasting climate analysis and climate change predictions - consider properties of fluids, chemical reactions and how organisms affect their environment |
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What is the role of International Cooperation in dealing with climate change?
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- the UNEP and the WMO created the IPCC to address global concerns about climate change and global warming
- IPCC assesses the human impact on climate change and environmental, social and economic issues related to climate change - UNFCCC created a voluntary treaty to encourage countries to reduce greenhouse gas emissions |
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What are global impacts of climate change?
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Temperature will increase in arctic regions and on land
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What are the impacts of climate change on Canada?
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- parts of Southern Canada will have average temperature increases of 0.5 -1.5 degrees
- greatest warming has occurred in the West - arctic regions are losing permafrost and ice cover -growing seasons are longer and more precipitation is falling - potential for heavier spring rains and longer heat waves - fisheries could experience changes to temperature, water quality and currents in bodies of water - high summer temperatures worsen effects of air pollution which worsens health issues - warmer winter temperatures allow insect pests to survive farther North than before |
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What are the impacts of climate change on BC?
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- sea level could rise up to 30 cm over the next 100 years
- change in weather patterns could bring more rain to some areas, drought to others - when glaciers shrink, drinking water will be harder to obtain - alteration of habitats, food supplies and shelter for wildlife |
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What does the UN suggest?
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countries should use the precautionary principle where the lack of complete scientific certainty should not be used as a reason to postpone cost-effective measures to prevent serious environmental damage
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Describe small changes that could have positive impacts on the climate in Canada
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- reduce greenhouse gas emissions from vehicles
- require industries to reduce greenhouse gas emissions - increase availability and use of energy-efficient products - set guidelines for improving indoor air quality |
