Atmosphere—The gaseous envelope surrounding a planet. The Earth’s atmosphere consists of nitrogen (79.1% by volume), oxygen (20.9% by volume), with about 0.04% carbon dioxide, and traces of argon, krypton, xenon, neon, and helium, plus water vapor, traces of ammonia, organic matter, ozone, various salts, and suspended solid particles.
Base Year—The year used as a reference year to help understand future emissions.
Biomass—Technically, the total dry organic matter or stored energy content of living organisms in a given area. Biomass refers to forms of living matter (e.g. grasses, trees) or their derivatives (e.g., ethanol, timber, charcoal) that can be used as fuels.
Carbon Cycle—General term used in reference to the sum of all reservoirs and flows of carbon on Earth. The flows tend to be cyclic in nature e.g. carbon removed from the atmosphere (one reservoir) and converted into plant tissue (another reservoir) is returned back into the atmosphere when the plant is burned or decomposes.
Carbon Sink or Reservoir—Within the carbon cycle, this is the physical site at which carbon is stored (e.g. atmosphere, oceans, Earth’s vegetation and soils, and fossil fuel deposits).
Carbon Dioxide—Carbon dioxide or CO2, essential to living systems, is released by animal respiration, decay of organic matter and fossil fuel burning. It is removed from the atmosphere by photosynthesis in green plants. The amount of CO2 in the atmosphere has increased by about 25% since the burning of coal and oil began on a large scale. Atmospheric carbon dioxide varies by a small amount with the seasons, and the ocean contains many times the amount of the gas that is in the atmosphere.
Carbon Dioxide Concentration—The atmospheric carbon dioxide concentration, at 398 parts per million volume (ppmv) in 2015, is now about 42% greater than the pre-industrial (1750-1800) value of about 280 ppmv, and higher than at any time in at least the last 160,000 years. Carbon dioxide is currently rising at about 1.8 ppmv (0.5%) per year due to human-caused emissions and currently accounts for approximately 84% of U.S. GHG emissions.
Chlorofluorocarbons (CFCs)—Compounds of carbon that contain some chlorine and some fluorine. CFCs do not occur naturally; they are synthetic products used in various industrial processes and also as propellant gas for sprays. CFCs are typically used in refrigerants, solvents, foam-makers and for use in aerosol sprays. CFCs are significant contributors to ozone depletion and also contribute to global warming. Replacement chemicals called hydroflourocarbons (HFC) do not deplete the ozone, but are strong contributors to global warming. These chemicals are slated to be replaced with even newer hydrocarbon compounds with minimal global warming impact.
Cities for Climate Protection Toolkit—ICLEI’s publication for the CCP containing a series of sections that help local government staff develop each portion of their Local Action Plan, along with a compendium of sample practices, case studies, and other tools.
Climate—The average weather together with its variability of representations of the weather conditions for a specified area during a specified time interval (usually decades or longer).
Cogeneration—The simultaneous generation and use of both electric power and heat; the heat, instead of being discharged without further use, is used in some fashion.
Corporate Average Fuel Economy—The Corporate Average Fuel Economy (CAFE) standards were originally established by Congress for new automobiles, and later for light trucks, in Title V of the Motor Vehicle Information and Cost Savings Act (15 U.S.C. 1901, et. seq.) with subsequent amendments. Under CAFE, automobile manufacturers are required by law to produce vehicle fleets with a composite sales-weighted fuel efficiency which cannot be lower than the CAFE standards in a given year. Standardized tests are used to rate the fuel economy of new vehicles. In 2000, CAFE standards are 27.5 mpg for cars and 20.7 mpg for light trucks.
Conference of the Parties (COP)—The COP comprises all the nations that have ratified or acceded to the UNFCCC or United Nations Framework Convention on Climate Change (over 175 by May 1999). It held its first meeting (COP-1) in Berlin in 1995 and will continue to meet on a yearly basis unless the Parties decide otherwise. The COP’s role is to promote and review the implementation of the Convention. It will periodically review existing commitments in light of the Convention’s objective, new scientific findings, and the effectiveness of national climate change programs. The COP can adopt new commitments through amendments and protocols to the Convention; in December 1997 it adopted the Kyoto Protocol containing stronger emissions-related commitments for developed countries in the post-2000 period. The 21st Congress of Parties took place in December 2015, in Paris, France.
Criteria Air Pollutants—The term criteria air pollutants refers to pollutants that are regulated under the U.S. Clean Air Act. As with carbon dioxide, the major sources of these pollutants are fossil fuels. Most measures that reduce carbon dioxide emissions also reduce criteria air pollutants. (Note that CO2 is not a criteria air pollutant.)
Equivalent CO2 (eCO2)—“Equivalent CO2” (eCO2), also known as Global Warming Potential weighted greenhouse gas emissions (GWP), is a unit, that allows emissions of greenhouse gases of different strengths to be added together. For carbon dioxide itself, emissions in tons of CO2 and tons of eCO2 are the same thing, whereas for methane, an example of a stronger greenhouse gas, one ton of methane emissions has the same GWP as 21 tons of CO2. Thus 1 ton of methane emissions can be expressed as 21 tons eCO2.
Ethanol Blend (E85)—Ethanol, or ethyl alcohol, is an alternative fuel that as of 1996 was available as a blend with regular gasoline.
Global Warming—The recent trend of increasing world-surface and tropospheric temperatures that scientists believe is caused by increased emissions of human-induced greenhouse gases. The greenhouse gases (CO2, methane, nitrous oxides and CFCs) are emitted into the atmosphere and increase the atmosphere’s “entrapment” of heat.
Global Warming Potential (GWP)—A concept developed by the IPCC that provides a comparative measure of the impacts of different greenhouse gases on global warming, with the effect of carbon dioxide being equal to 1. See also equivalent CO2 (eCO2).
Greenhouse Gases and the Greenhouse Effect—The Earth’s climate is determined by a delicate balance between the solar energy that arrives from space and the heat energy that the earth creates from the sun’s rays. The energy that arrives from space should always equal the energy that the earth emits back to space. When something disturbs this balance, our climate adjusts by cooling or warming the earth to return things to normal. A portion of outgoing heat energy is absorbed in the atmosphere by greenhouse gases such as water vapor, carbon dioxide, methane, and nitrous oxide. If these trace gases were not present, the average temperature on the earth’s surface would be -32 degrees Fahrenheit, and life as we know it would not have evolved here. But the natural greenhouse effect keeps the average global surface temperature at a comfortable 59 degrees Fahrenheit. Human activities are currently emitting the equivalent of 8.3 billion tons of carbon annually in the form of carbon dioxide into the atmosphere. About 60% of this carbon is reabsorbed by trees, plants, and the ocean. But the remaining 40% increases the atmospheric level of greenhouse gases and magnifies the natural greenhouse effect, leading to global warming.
The concentration of the most important greenhouse gas, carbon dioxide, has already increased by 42% since the beginning of industrialization. This increase is the result of an increased reliance on fossil fuels and deforestation, which has caused an imbalance between the absorption and release of carbon dioxide by vegetation. Other greenhouse gases, also found in the atmosphere in increasing amounts, are methane, nitrous oxide and the chlorofluorocarbons (CFCs).
IPCC—Intergovernmental Panel on Climate Change—The Intergovernmental Panel on Climate Change (IPCC) was jointly established in 1988 by the World Meteorological Organization and the United Nations Environment Program to assess available scientific information on climate change, assess the environmental and socio-economic impacts of climate change, and formulate response strategies.
It has emerged as the predominant international forum for the development of scientific knowledge and policy advice on matters related to climate change. Its periodic Assessment Reports are relied upon by governments to guide policy making on this issue. In its 1995 Technical Report, the IPCC stated that global warming is happening and is at least in part due to human activities.
Kyoto Protocol—Adopted by consensus at the third session of the Conference of the Parties (COP-3) in December 1997 in Kyoto, Japan. When ratified by a certain % of participating countries, it contains legally binding emissions targets for developed countries in the post-2000 period. By arresting and reversing the upward trend in greenhouse gas emissions that started in these countries 150 years ago, the Protocol promises to move the international community one step closer to achieving the Convention’s ultimate objective of preventing “dangerous anthropogenic [human-induced] interference with the climate system.”
In the Protocol, developed countries commit themselves to reducing their collective emissions of six key greenhouse gases by at least 5%. This group target will be achieved through cuts of 8% by Switzerland, most Central and East European states, and the European Union (the EU will meet its target by distributing different rates among its member states); 7% by the US; and 6% by Canada, Hungary, Japan, and Poland. Russia, New Zealand, and Ukraine are to stabilize their emissions, while Norway may increase emissions by up to 1%, Australia by up to 8%, and Iceland 10%. The six gases are to be combined in a “basket”, with reductions in individual gases translated into “CO2 equivalents” that are then added up to produce a single figure. As of 1999, the Kyoto Protocol had not yet been ratified by the required number of countries.
Local Action Plan—Milestone 3 of the CCP, this is the Plan that describes the actions a local government will take to reduce its GHG emissions. The Local Action Plan also includes the Emissions Analysis, Emissions Reduction Target and an implementation strategy.
Methane—Methane or CH4, which accounts for about 9% of U.S. eCO2 or GWP weighted GHG emissions, is produced by anaerobic decomposition of solid waste in landfills and sewage treatment facilities, wetlands and rice paddies, as a byproduct of fossil fuel energy production and transport and also from out gassing in livestock. It is also the principle constituent of natural gas and can leak from natural gas production and distribution systems and is emitted in the process of coal production. The methane concentration in the atmosphere has been rising steadily for several centuries, keeping pace with the increase in the world population and expansion of the world economy.
Nitrous Oxide—Nitrous oxide or N20 (not to be confused with nitrogen oxides or NOx) is a potent greenhouse gas accounting for about 5% of U.S. eCO2 emissions. Main sources for this GHG is nitrogen fertilization of agricultural soils, agricultural run-off and also from motor vehicles equipped with catalytic converters.
Ozone—An ozone molecule consists of three atoms of oxygen. In contrast, the normal oxygen in the atmosphere exists as a molecule with two atoms of oxygen. Ozone is much more reactive than oxygen and is toxic to human beings and living matter. At ground level it forms smog and causes damage to forests and humans. (In the stratosphere, it functions mainly as a filter for ultra-violet radiation and to a lesser extent as a greenhouse gas.) Ground level ozone formation is closely connected to climate change since the sources of emissions that cause it such as motor vehicle use, are also global warming pollutants. Additionally, the formation of ground level ozone requires not only pollutants but also heat and sunlight—As regions get hotter due to global warming, ozone smog increases.
Stratosphere—Layer of the atmosphere above the troposphere extending to a height of ~ 50 km.
Troposphere—Lowest layer of the atmosphere where almost all weather phenomena develop.
UNFCCC—The United Nations Framework Convention on Climate Change is the foundation of global efforts to combat global warming. Opened for signature at the Rio Earth Summit in 1992, its ultimate objective is the “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic [human-induced] interference with the climate system. Such a level should be achieved within a timeframe sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.” See also Conference of Parties.
Urban CO2 Reduction Project—A pre-cursor to the Cities for Climate Protection Campaign, this project involved local governments from U.S., Europe and Canada including: Portland, OR, San Jose, CA, Denver, CO, Saint Paul and Minneapolis, MN, Miami-Dade County, FL and Chula Vista, CA.
[Content for this page generously provided by ICLEI.]