Planting of new forests on lands that have not been recently forested.

Alternative Energy

Energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind).

Anthropogenic Emissions

Emissions of greenhouse gasses resulting from human activities.


The gaseous envelope surrounding the Earth. The dry atmosphere consists almost entirely of nitrogen and oxygen, together with a number of trace gases, such as argon, helium, and radioactive greenhouse gases, such as carbon dioxide, and ozone. In addition, the atmosphere contains water vapor. The atmosphere also contains clouds and aerosols.

Bali Conference

The Conference, hosted by the Government of Indonesia, took place from December 3 to December 15, 2007. More than 10,000 participants attended, including representatives from over 180 countries, observers from intergovernmental and nongovernmental organizations and the media. The two week period included the sessions of the Conference of the Parties to the UNFCCC, its subsidiary bodies as well as the Meeting of the Parties to the Kyoto Protocol. The conference culminated in the adoption of the Bali Road Map, containing the Bali Action Plan, which charts the course for a new negotiating process designed to tackle climate change, with the aim of completing this by 2009. It also includes the AWG-KP negotiations and their 2009 deadline, the launch of the Adaptation Fund, the scope and content of the Article 9 review of the Kyoto Protocol, as well as decisions on technology transfer and on reducing emissions from deforestation.

Base Year

The year that is used as the basis of comparison for the level of greenhouse gas emissions measured thereafter. In the Kyoto Protocol, 1990 is the base year for most countries for the major greenhouse gasses (GHG’s); 1995 can be used as the base year for some of the minor GHGs.


The part of the Earth system comprising all ecosystems and living organisms, in the atmosphere, on land (terrestrial biosphere) or in the oceans (marine biosphere), including derived dead organic matter, such as litter, soil organic matter and oceanic detritus.

Cap and Trade

An administrative approach used to control emissions by providing economic incentives for achieving reductions in the emissions of pollutants. A central authority (usually a government or international body) sets a limit or cap on the amount of a pollutant that can be emitted. Industries, companies or other groups are issued emission permits which represent the right to emit a specific amount. The total amount of allowances and credits cannot exceed the cap, limiting total emissions to that level. If a company needs to decrease its emissions, it must buy credits from those who pollute less. The transfer of allowances is referred to as a trade. In effect, the buyer is paying a charge for polluting, while the seller is being rewarded for having reduced emissions by more than was needed (Montgomery, W.D. “Markets in Licenses and Efficient Pollution Control Programs.” Journal of Economic Theory 5 (Dec 1972):395-418)

Carbon Dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth’s atmosphere in this state. It is currently at a globally averaged concentration of approximately 387 ppm by volume in the Earth’s atmosphere. Carbon dioxide is produced during respiration by plants, and by all animals, fungi and microorganisms that depend on living and decaying plants for food, either directly or indirectly. It is, therefore, a major component of the carbon cycle. Carbon dioxide is a greenhouse gas, and is generated as a by-product of the combustion of fossil fuels or the burning of vegetable matter, among other chemical processes. In the 1960s, the average annual increase was 37% of the 2000-2007 average. Due to human activities such as the combustion of fossil fuels and deforestation, and the increased release of CO2 from the oceans due to the increase in the Earth’s temperature, the concentration of atmospheric carbon dioxide has increased by about 35% since the beginning of the age of industrialization..

Carbon Dioxide Equivalent (CO2e)

Carbon dioxide equivalency is a quantity that describes, for a given mixture and amount of greenhouse gas, the amount of CO2 that would have the same global warming potential (GWP), when measured over a specified timescale (generally, 100 years). It is a unit of measurement for greenhouse gas emissions. For example, the GWP for methane over 100 years is 25 and for nitrous oxide 298. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively are equivalent to emissions of 25 and 298 million metric tonnes of carbon dioxide.

Carbon Footprint

A measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide (ISA-UK Report 07-01).

Carbon Neutral

Refers to achieving net-zero carbon emissions by balancing a measured amount of carbon released into the atmosphere with an equivalent amount offset.

Carbon Offset

A financial instrument representing a reduction in greenhouse gas emissions. Carbon offsets are measured in metric tons of carbon dioxide-equivalent (CO2e). One carbon offset represents the reduction of one metric ton of carbon dioxide, or its equivalent in other greenhouse gases.

Carbon Tax

An environmental tax on emissions of carbon dioxide and other greenhouse gases. It is an example of a pollution tax. This is an alternative to a cap and trade scheme.


CFCs are synthetic industrial gases composed of chlorine, fluorine, and carbon. They have been used as refrigerants, aerosol propellants, cleaning solvents and in the manufacture of plastic foam. There are no natural sources of CFCs. CFCs have an atmospheric lifetime of decades to centuries, and they have 100-year “global warming potentials” thousands of times that of CO2, depending on the gas. In addition to being greenhouse gases, CFCs also contribute to ozone depletion in the stratosphere and are controlled under the Montreal Protocol.

Clean Development Mechanism (CDM)

One of the three market mechanisms established by the Kyoto Protocol. The CDM is designed to promote sustainable development in developing countries and assist developed countries to meet their greenhouse gas emissions reduction commitments. It enables industrialized countries to invest in emission reduction projects in developing countries and to receive credits for reductions achieved.


Climate is the average weather conditions at a particular place over a long period of time. Climate is the long-term predictable state of the atmosphere. It is affected by physical features such as mountains, rivers, positioning of the globe, plateaus, deserts, depressions and much more. The major elements of weather and climate: temperature, air pressure, wind, precipitation, relative humidity, and sunshine. They help people to describe the conditions of weather and climate. The climate of a place is given names such as Temperate, Arid, Cold, Dry, Tundra, Tropical, Equatorial, Mediterranean, Savanna, etc.

Climate Change

Refers to changes in long-term trends in the average climate, such as changes in average temperatures.


Practices or processes that result in the conversion of forested lands for 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.


Land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities.


A community of organisms and its physical environment.


The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere.

Emissions Cap

A mandated restraint, often in a scheduled timeframe, that puts a “ceiling” on the total amount of anthropogenic greenhouse gas emissions that can be released into the atmosphere.

Emissions Trading

A market mechanism that allows emitters (countries, companies or facilities) to buy emissions from or sell emissions to other emitters. Emissions trading is expected to bring down the costs of meeting emission targets by allowing those who can achieve reductions less expensively to sell excess reductions (e.g. reductions in excess of those required under some regulation) to those for whom achieving reductions is more costly.

Enhanced Greenhouse Effect

The increase in the natural greenhouse effect resulting from increases in atmospheric concentrations of greenhouse gasses due to emissions from human activities.

Feedback Mechanisms

Factors which increase or amplify (positive feedback) or decrease (negative feedback) the rate of a process.

Global Warming

The progressive gradual rise of the Earth’s average surface temperature thought to be caused in part by increased concentrations of GHGs in the atmosphere. Global warming can occur from a variety of causes, both natural and human induced.


We tend to use “sustainable” or “energy-efficient” instead of “green” because the word has come to espouse such a variety of meanings that it has become too vague. However, it generally refers to advocating, supporting or promoting protection of environment. When referring to products, “green” usually indicates the products were produced in an environmentally and ecologically friendly way.

Greenhouse Effect

The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapour, carbon dioxide, nitrous oxide, and methane) trap energy from the Sun. Because of how they warm our world, these gases are referred to as greenhouse gases. Sunlight enters the Earth’s atmosphere, passing through the blanket of greenhouse gases. As it reaches the Earth’s surface, land, water, and biosphere absorb the sunlight’s energy. Some of this energy is reflected, or absorbed and re-radiated, back into space. But much of it remains trapped in the atmosphere by the greenhouse gases, causing our world to heat up. Without the greenhouse effect, the Earth would not be warm enough for humans to live. But if the greenhouse effect becomes stronger, it could make the Earth warmer than usual. Even a little extra warming, particularly if it occurs rapidly, may cause problems for humans, plants, and animals.

Greenhouse Gas (GHG)

Any gas that absorbs infrared radiation in the atmosphere, and thus contribute to the “greenhouse effect.” Greenhouse gases include, but are not limited to, water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3 ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

Greenhouse Gas Inventory

A list of the sources of an organization’s sources of GHG emissions, and their quantities. The process requires defining organizational boundaries, and identifying and measuring all sources of emissions. Includes direct emissions (emissions from sources that a company owns/controls), and indirect emissions (which result from an organizations’ activities but from sources owned/controlled by another company, such as electricity.) (World Resources Institute).

Intergovernmental Panel on Climate Change (IPCC)

The IPCC was established in 1988 by the World Meteorological Organization and the UN Environment Programme. The IPCC is responsible for providing the scientific and technical foundation for the United Nations Framework Convention on Climate Change (UNFCC), primarily through the publication of periodic assessment reports. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is considered the official advisory body to the world’s governments on the state of the science of the climate change issue.

Kyoto Protocol

An international agreement adopted in December 1997 in Kyoto, Japan. The Protocol sets binding emission targets for developed countries that would reduce their emissions on average 5.2 percent below 1990 levels.


Land waste disposal site in which waste is generally spread in thin layers, compacted, and covered with a fresh layer of soil each day.

Methane (CH4)

A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 23 times that of carbon dioxide (CO2). 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 petroleum, coal production, and incomplete fossil fuel combustion. CH4 has a relatively short atmospheric lifetime of approximately 10 years, but its 100-year GWP is currently estimated to be approximately 25 times that of CO2.

Metric Ton

Common international measurement for the quantity of greenhouse gas emissions. A metric ton is equal to 2205 lbs or 1.1 short tons.

Natural Gas

Natural gas is a gaseous fossil fuel consisting primarily of methane but including significant quantities of ethane, propane, butane, and pentane–heavier hydrocarbons removed prior to use as a consumer fuel –as well as carbon dioxide, nitrogen, helium and hydrogen sulfide.

Natural gas is a major source of electricity generation through the use of gas turbines and steam turbines. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Natural gas burns cleaner than other fossil fuels, such as oil and coal, and produces less carbon dioxide per unit energy released. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. Combined cycle power generation using natural gas is thus the cleanest source of power available using fossil fuels, and this technology is widely used wherever gas can be obtained at a reasonable cost.

ppm or ppb

Abbreviations for “parts per million” and “parts per billion,” respectively – the units in which concentrations of greenhouse gases are commonly presented. For example, since the pre-industrial era, atmospheric concentrations of carbon dioxide have increased from 270 ppm to 370 ppm.


Collecting and reprocessing a resource so it can be used again. An example is collecting aluminum cans, melting them down, and using the aluminum to make new cans or other aluminum products.


Planting of forests on lands that have previously contained forests but that have been converted to some other use.

Renewable Energy

Renewable energy is energy generated from natural resources—such as sunlight, wind, rain, tides and geothermal heat—which are renewable (naturally replenished). In 2006, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood-burning. Hydroelectricity was the next largest renewable source, providing 3%, followed by solar hot water/heating, which contributed 1.3%. Modern technologies, such as geothermal energy, wind power, solar power, and ocean energy together provided some 0.8% of final energy consumption.

Short Ton

Common measurement for a ton in the United States. A short ton is equal to 2,000 lbs or 0.907 metric tons.


Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere. For example, a forest is a carbon sink because it stores carbon dioxide and hence removes it from the atmosphere.


In the most general sense, sustainability is the capacity to maintain a certain process or state indefinitely. The EPA defines the term more specifically as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.”

United Nations Framework Convention on Climate Change (UNFCCC)

A treaty signed at the 1992 Earth Summit in Rio de Janeiro that calls for the “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.” The treaty includes a non-binding call for developed countries to return their emissions to 1990 levels by the year 2000. The treaty took effect in March 1994 upon ratification by more than 50 countries. The United States was the first industrialized nation to ratify the Convention.

Under the Convention, governments:


Describes the short-term (i.e., hourly and daily) state of the atmosphere. Weather is not the same as climate.