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The planting of new forests on land that historically have not contained forests.
The fraction of incident radiation reflected by a surface. For example, in terms of visible light, white surfaces tend to be highly reflective, while darker surfaces tend to absorb more incoming radiation. Albedo can be expressed as either a percentage or a fraction of 1. Snow and ice covered areas have a high albedo (approximately 0.8 or 80%) due to their white color, while vegetation has a low albedo due to the dark color and light absorbed for photosynthesis. The Earth's aggregate albedo is approximately 0.3 or 30%.
Inaugurated on August 26 2003, the CCGS Amundsen is one of the few Canadian Coast Guard vessels to have a dual purpose. During half the year, the Amundsen is reserved for exclusive use by a Canadian-led scientific consortium, such as the Canadian Arctic Shelf Exchange Study, while the other half remains dedicated to the Coast Guard's icebreaking operations. The CCGS Amundsen was newly named after Roald Amundsen, a notable Norwegian explorer of the Canadian Arctic who was the first person to navigate the Northwest Passage 100 years ago, from 1903 to 1906. In 1911, he was also the first person to reach the South Pole.
Resulting from or produced by human beings.
The mixture of gases surrounding the Earth. The Earth's atmosphere consists of about 79.1% nitrogen (by volume), 20.9% oxygen, 0.036% carbon dioxide and trace amounts of other gases. The atmosphere can be divided into a number of layers according to its mixing or chemical characteristics. The layer nearest the Earth is the troposphere, which reaches up to an altitude of about 8 km in the polar regions and up to 17 km above the equator. The stratosphere, which reaches to an altitude of about 50 km lies atop the troposphere. The mesosphere which extends up to 80-90 km is atop the stratosphere, and finally, the thermosphere, or ionosphere, gradually diminishes and forms a fuzzy border with outer space. There is relatively little mixing of gases between layers.
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The numbers and relative abundances of different genes, species, and ecosystems in a particular area.
The chemical interactions that take place among the atmosphere, biosphere, hydrosphere, and geosphere.
Organic non-fossil material of biological origin. For example, trees and plants are biomass.
A naturally occurring community of flora and fauna (or the region occupied by such a community) adapted to the particular conditions in which they occur (e.g. tundra).
The region on land, in the oceans, and in the atmosphere inhabited by living organisms.
Forests of pine, spruce, fir, and larch stretching from the east coast of Canada westward to Alaska and continuing from Siberia across the entire extent of Russia to the European Plain.
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The Canadian Arctic Shelf Exchange Study research network is an international effort under Canadian leadership to understand and model the response of biogeochemical and ecological cycles to atmospheric, oceanic and continental forcing of sea ice cover variability on the Mackenzie Shelf. In Canada, the CASES research network brings together 45 academic researchers from 13 different universities, four Federal Departments and the Canadian Museum of Nature.
The global scale exchange of carbon among its reservoirs, namely the atmosphere, oceans, vegetation, soils, and geologic deposits and minerals. This involves components in food chains, in the atmosphere as carbon dioxide, in the hydrosphere and in the geosphere.
The greenhouse gas whose concentration is being most affected directly by human activities. CO2 also serves as the reference to compare all other greenhouse gases (see carbon dioxide equivalents). The major source of CO2 emissions is fossil fuel combustion. CO2 emissions are also a product of forest clearing, biomass burning, and non-energy production processes such as cement production. Atmospheric concentrations of CO2 have been increasing at a rate of about 0.5% per year and are now about 30% above pre-industrial levels.
A metric measure used to compare the emissions from various greenhouse gases based upon their global warming potential (GWP). Carbon dioxide equivalents are commonly expressed as "million metric tons of carbon dioxide equivalents (MMTCDE)". The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by the associated GWP. For example, the GWP for methane is 24.5. This means that emissions of one million metric tons of methane is equivalent to emissions of 24.5 million metric tons of carbon dioxide.
The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen and store the carbon. Fossil fuels were at one time biomass and continue to store the carbon until burned.
Carbon reservoirs and conditions that take in and store more carbon (carbon sequestration) than they release. Carbon sinks can serve to partially offset greenhouse gas emissions. Forests and oceans are common carbon sinks.
The average weather (usually taken over a 30-year time period) for a particular region and time period. Climate is not the same as weather, but rather, it is the average pattern of weather for a particular region. Weather describes the short-term state of the atmosphere. Climatic elements include precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and hail storms, and other measures of the weather.
The term "climate change" is sometimes used to refer to all forms of climatic inconsistency, but because the Earth's climate is never static, the term is more properly used to imply a significant change from one climatic condition to another. In some cases, "climate change" has been used synonymously with the term, "global warming"; scientists however, tend to use the term in the wider sense to also include natural changes in climate.
A plausible and often simplified representation of the future climate that has been constructed for use in investigating the potential consequences of anthropogenic climate change.
The frozen part of the Earth's surface. The cryosphere includes the polar ice caps, continental ice sheets, mountain glaciers, sea ice, snow cover, lake and river ice, and permafrost.
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Those practices or processes that result in the change of forested lands to non-forest uses. This is often cited as one of the major causes of the enhanced greenhouse effect for two reasons: 1) the burning or decomposition of the wood releases carbon dioxide; and 2) trees that once removed carbon dioxide from the atmosphere in the process of photosynthesis are no longer present and contributing to carbon storage.
The progressive destruction or degradation of existing vegetative cover to form desert. This can occur due to overgrazing, deforestation, drought, and the burning of extensive areas. Once formed, deserts can only support a sparse range of vegetation. Climatic effects associated with this phenomenon include increased albedo, reduced atmospheric humidity, and greater atmospheric dust (aerosol) loading.
A class of unicellular algae (Bacillariophyceae) having siliceous cell walls that persist as glass-like skeletons long after death. They are abundant in both fresh and salt waters and their remains are widely distributed in soils where they form deposits. These deposits contain a wealth of information on past environments and climates.
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A climatic phenomenon occurring irregularly, but generally every three to five years. El Ninos often first become evident during the Christmas season (El Nino means Christ child) in the surface oceans of the eastern tropical Pacific Ocean. The phenomenon involves seasonal changes in the direction of the tropical winds over the Pacific and abnormally warm surface ocean temperatures. The changes in the tropics are most intense in the Pacific region; these changes can disrupt weather patterns throughout the tropics and can extend to higher latitudes, especially in Central and North America. The relationship between these events and global weather patterns are currently the subject of much research in order to enhance prediction of seasonal to interannual fluctuations in the climate.
The nature and degree to which a system (region, community) is exposed to significant climatic variations.
A weather event that occurs infrequently at a particular place and that is usually (but not necessarily) hazardous (potential for causing significant damage). By definition, the characteristics of what is called "extreme weather" may vary from place to place. For example, abundant snowfall during an Ottawa winter is not considered "extreme" insomuch as it would during a Kenyan winter.
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A mechanism that connects one aspect of a system to another. The connection can be either amplifying (positive feedback) or moderating (negative feedback).
A process that alters the energy balance of the climate system, i.e. changes the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. Such mechanisms include changes in solar irradiance, volcanic eruptions, and enhancement of the natural greenhouse effect by emission of carbon dioxide. See also Radiative Forcing.
A general term for combustible geologic deposits of carbon in reduced (organic) form and of biological origin, including coal, oil, natural gas, oil shales, and tar sands. A major concern is that they emit carbon dioxide into the atmosphere when burned, thus significantly contributing to the enhanced greenhouse effect.
Burning of coal, oil (including gasoline), or natural gas. This burning, usually to generate energy, releases carbon dioxide, as well as combustion by products that can include unburned hydrocarbons, methane, and carbon monoxide. Carbon monoxide, methane, and many of the unburned hydrocarbons slowly oxidize into carbon dioxide in the atmosphere. Common sources of fossil fuel combustion include cars and electric utilities.
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A global, three-dimensional computer model of the climate system which can be used to simulate human-induced climate change. GCMs are highly complex and they represent the effects of such factors as reflective and absorptive properties of atmospheric water vapor, greenhouse gas concentrations, clouds, annual and daily solar heating, ocean temperatures and ice boundaries. The most recent GCMs include global representations of the atmosphere, oceans, and land surface.
A mass of land ice maintained by the accumulation of snow at high latitudes, balanced by melting at low altitudes or discharge into the sea. Glacier ice can also take the form of a sheet such as those on Greenland and Antarctica, or of a shelf where a floating ice sheet is attached to a coast as a seaward extensions of ice sheets. The melting of glacier ice is a contributing factor to sea level rise as land bound ice melts into the sea.
An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases. Scientists generally agree that the Earth's surface has warmed by about 1 degree Fahrenheit in the past 140 years. The Intergovernmental Panel on Climate Change (IPCC) recently concluded that increased concentrations of greenhouse gases are causing an increase in the Earth's surface temperature and that increased concentrations of sulfate aerosols have led to relative cooling in some regions, generally over and downwind of heavily industrialized areas. Also see Climate Change.
The index used to translate the level of emissions of various gases into a common measure in order to compare the relative radiative forcing of different gases without directly calculating the changes in atmospheric concentrations. GWPs are calculated as the ratio of the radiative forcing that would result from the emissions of one kilogram of a greenhouse gas to that from emission of one kilogram of carbon dioxide over a period of time (usually 100 years). Gases involved in complex atmospheric chemical processes have not been assigned GWPs due to complications that arise. Greenhouse gases are expressed in terms of Carbon Dioxide Equivalent. The International Panel on Climate Change (IPCC) has presented these GWPs and regularly updates them in new assessments.
The effect produced as greenhouse gases allow incoming solar radiation to pass through the Earth's atmosphere, but prevent most of the outgoing infrared radiation from the surface and lower atmosphere from escaping into outer space. This process occurs naturally and has kept the Earth's temperature about 15 degrees Celsius warmer than it would otherwise be. Current life on Earth could not be sustained without the natural greenhouse effect.
Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), halogenated fluorocarbons (HCFCs) , ozone (O3), perfluorinated carbons (PFCs), and hydrofluorocarbons (HFCs).
-H-
These chemicals (along with perfluorocarbons) were introduced as alternatives to ozone depleting substances in serving many industrial, commercial, and personal needs. HFCs are emitted as by-products of industrial processes and are also used in manufacturing. They do not significantly deplete the stratospheric ozone layer, but they are powerful greenhouse gases with global warming potentials ranging from 140 (HFC-152a) to 12,100 (HFC-23).
The part of the Earth composed of water including clouds, oceans, seas, ice caps, glaciers, lakes, rivers, underground water supplies, and atmospheric water vapor.
-I-
A cylindrical section of ice removed from a glacier or an ice sheet in order to study climate patterns of the past. By performing chemical analyses on the air trapped in the ice, scientists can estimate the percentage of carbon dioxide and other trace gases in the atmosphere at that time.
The heat energy that is emitted from all solids, liquids, and gases. In the context of the greenhouse issue, the term refers to the heat energy emitted by the Earth's surface and its atmosphere. Greenhouse gases strongly absorb this radiation in the Earth's atmosphere, and reradiate some back towards the surface, creating the greenhouse effect.
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Part of the Yukon's St. Elias mountain range, at 5,959 m, Mt. Logan towers over all other mountains in Canada, and all but one in North America (Mt. McKinley, Alaska, 6,194 m). Its base probably covers more area than any other mountain massif in the world and it is named after the founder of the Geological Survey of Canada, Sir William Edmond Logan.
-M-
The science of weather-related phenomena.
A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 24.5. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and oil, coal production , and incomplete fossil fuel combustion. The atmospheric concentration of methane has been shown to be increasing at a rate of about 0.6% per year and the concentration of about 1.7 parts per million by volume (ppmv) is more than twice its preindustrial value. However, the rate of increase of methane in the atmosphere may be stabilizing.
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A powerful greenhouse gas with a global warming potential of 320. Major sources of nitrous oxide include soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
The Northwest Passage is a navigational route between the Atlantic and Pacific oceans through the Canadian Arctic archipelago. While past voyages across this fabled route have been successful (see Amundsen), regular maritime transport remains too treacherous even during its brief ice-free period. Such transport may eventually become commonplace as its waters fail to freeze for much of the year due to climate warming in the Arctic.
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The theoretical route by which water circulates around the entire ocean, driven by wind and the thermomaline circulation.
Ozone consists of three atoms of oxygen bonded together in contrast to normal atmospheric oxygen which consists of two atoms of oxygen. Ozone is an important greenhouse gas found in both the stratosphere (about 90% of the total atmospheric loading) and the troposphere (about 10%). Ozone has other effects beyond acting as a greenhouse gas. In the stratosphere, ozone provides a protective layer shielding the Earth from ultraviolet radiation and subsequent harmful health effect on humans and the environment. In the troposphere, oxygen molecules in ozone combine with other chemicals and gases (oxidization) to cause smog.
-P-
Perennially frozen ground that occurs wherever temperatures remain below 0ºC for several years.
The process by which green plants use light captured by chlorophyll to synthesize organic compounds from carbon dioxide and water. Oxygen is released in the process. Increased levels of carbon dioxide can increase net photosynthesis in some plants. Plants create a very important reservoir for carbon dioxide.
Mt. Pinatubo violently erupted in June 1991 in the faraway Philippines, spewing more than 5 billion cubic meters of ash. For months, the ejected volcanic materials remained suspended in the atmosphere where the winds dispersed them to envelope the earth. This phenomenon temporarily caused the world's temperature to fall by an average of 1 degree Celsius.
Strictly, too much of any substance in the wrong place or at the wrong time is a pollutant. More specifically, atmospheric pollution may be defined as the presence of substances in the atmosphere, resulting from man-made activities or from natural processes that cause adverse effects to human health, property, and the environment. Greenhouse gases are not necessarily pollutants and pollutants are not necessarily greenhouse gases.
Areas of open water in pack ice or sea ice.
The tendency of the Earth's axis to wobble in space over a period of 23,000 years. The Earth's precession is one of the factors that results in the planet receiving different amounts of solar energy over extended periods of time.
Energy embodied in natural resources that has not undergone any conversion or transformation by human activity.
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Energy emitted in the form of electromagnetic waves. Radiation has differing characteristics depending upon the wavelength. Because the radiation from the Sun is relatively energetic, it has a short wavelength (ultraviolet, visible, and near infrared) while energy reradiated from the Earth's surface and the atmosphere has a longer wavelength (infrared radiation) because the Earth is cooler than the Sun.
A change in the balance between incoming solar radiation and outgoing infrared radiation. Without any radiative forcing, solar radiation coming to the Earth would continue to be approximately equal to the infrared radiation emitted from the Earth. The addition of greenhouse gases traps and increased fraction of the infrared radiation, reradiating it back toward the surface and creating a warming influence (i.e., positive radiative forcing because incoming solar radiation will exceed outgoing infrared radiation).
Planting of forests on land which has historically contained forest but which has been used for another purpose since last being covered by forest.
The renewal of a stand of trees through either natural means (deposited by wind or animals) or artificial means (panting seedlings or direct seeding).
-S-
The accumulation of salts in soils.
An increase in the mean level of the ocean. This can occur through the melting and runoff of glacier ice into the sea and by the thermal expansion of water as it absorbs more heat and increases in volume.
The latitudinal ocean area that is covered by ice at any given time. Maximum extent occurs in late winter/early spring while minimum extent occurs in late summer/early fall.
Inuit word meaning weather, climate systems, and all that surrounds us.
Any process, activity, or mechanism that removes a greenhouse gas (or its precursor) from the atmosphere. Soil, oceans and trees tend to act as natural sinks for carbon.
A seasonal accumulation of slow-melting snow.
A measure of the brightness of (i.e. the amount of solar radiation being emitted by the Sun.
Energy from the Sun. Also referred to as short-wave radiation. Of importance to the climate system, solar radiation includes ultraviolet radiation, visible radiation, and infrared radiation.
Any process or activity which releases a greenhouse gas (or its precursor) into the atmosphere.
A rise in the water level in relation to the land; it results either from a sinking of the land or from a rise of the water level.
A compound composed of one sulfur and two oxygen molecules. Sulfur dioxide emitted into the atmosphere through natural and anthropogenic processes is changed in a complex series of chemical reactions in the atmosphere to sulfate aerosols. These aerosols result in negative radiative forcing (i.e., tending to cool the Earth's surface).
Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
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Coniferous forests of northern North America and Eurasia.
A collective term for all living organisms on land.
Large-scale density-driven circulation in the oceans, driven by differences in temperature and salinity. In the North Atlantic, the thermohaline circulation consists of warm surface water flowing northward and cold deepwater flowing southward. The surface water sinks in highly restricted sinking regions located in high latitudes.
The upper limit of tree growth in mountains or high latitudes.
Any one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia, are considered trace gases. Although relatively unimportant in terms of their absolute volume, they have significant effects on the Earth's weather and climate.
A treeless, level, or gently undulating plain characteristic of arctic and subarctic regions.
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Solar (shortwave) radiation, the greater part of which is absorbed by stratospheric ozone. Enhanced UV-B radiation suppresses the immune system and can have other adverse effects on living organisms.
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An organism, such as an insect, that transmits a pathogen from one host to another.
The degree to which a system (region, community) is unable to cope with adverse effects of climate change. Vulnerability is a function of the character, magnitude, and rate of climate variation to which a system is exposed, and its ability to adapt to these changes.
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The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form. Water vapour is an important part of the natural greenhouse effect. While humans are not significantly increasing its concentration, it contributes to the enhanced greenhouse effect because the warming influence of greenhouse gases leads to a positive water vapour feedback. In addition to its role as a natural greenhouse gas, water vapour plays an important role in regulating the temperature of the planet because clouds form when excess water vapour in the atmosphere condenses to form ice and water droplets and precipitation.
Weather is the specific condition of the atmosphere at a particular place and time. It is measured in terms of such things as wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation. In most places, weather can change from hour-to-hour, day-to-day, and season-to-season. Climate is the average of weather over time and space. A simple way of remembering the difference is that 'climate' is what you expect (e.g., cold winters) and 'weather' is what you get (e.g., a blizzard).
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-Z-
- Canadian Arctic Shelf Exchange Program
- Environnement Canada
- Fisheries and Oceans Canada
- Geological Survey of Canada
- L.D. Danny Harvey, 2000
- United Nations Environment Programme
- United Nations Intergovernmental Panel on Climate Change, 2001
- United States Environmental Protection Agency
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