Glossary of Terms

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

Agricultural Enterprises: A broad range of agricultural activities on the same property.

Animal Emissions (IPCC calculations): Gas emissions from sheep, cattle and other farm livestock are based on the simplified IPCC calculations. These figures do not take into account changes in feed quality or age of livestock.

Anthropogenic Emissions: Emissions of greenhouse gasses resulting from human activities.

Calculation Information: All emissions are represented in relation to carbon dioxide and its Global Warming Potential (GWP) and expressed as carbon dioxide equivalents (CO₂-e). Carbon dioxide (CO₂) is produced on combustion of fuels and during cultivation of soils. Methane (CH₄) is a gas produced by animals and has a Global Warming Potential equivalent to 23 times CO₂ molecules. Nitrous oxide (N₂O) is emitted from nitrogen sources, including fertilisers, urine and dung and has a Global Warming Potential 296 times that of CO₂. CO₂-e = 1 * CO₂ emitted + 23 * CH₄ emitted + 296 * N₂O emitted.

Carbon Dioxide (CO₂): CO₂ is a colorless, odorless, non-poisonous gas that is a normal part of the ambient air. Of the six greenhouse gases normally targeted, CO₂ contributes the most to human-induced global warming. Human activities such as fossil fuel combustion and deforestation have increased atmospheric concentrations of CO₂ by approximately 30 percent since the industrial revolution. CO₂ is the standard used to determine the "global warming potentials" (GWPs) of other gases. CO₂ has been assigned a 100-year GWP of 1 (i.e., the warming effects over a 100-year time frame relative to other gases).

Carbon Sinks: Processes that remove more carbon dioxide from the atmosphere than they release. Both the terrestrial biosphere and oceans can act as carbon sinks.

Climate: The long-term average weather of a region including typical weather patterns, the frequency and intensity of storms, cold spells, and heat waves. Climate is not the same as weather. The decomposition of soil organic matter, crop residues and stubbles is dependent on heat and moisture.

Climate Change: Refers to changes in long-term trends in the average climate, such as changes in average temperatures. In IPCC usage, climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity. In UNFCC usage, climate change refers to a change in climate that is attributable directly or indirectly to human activity that alters atmospheric composition.

Climate Sensitivity: The average global air surface temperature change resulting from a doubling of pre-industrial atmospheric CO₂ concentrations. The IPCC estimates climate sensitivity at 1.5-4.5^oC (2.7-8.1^oF).

Climate Variability: Refers to changes in patterns, such as precipitation patterns, in the weather and climate.

Ecosystem: A community of organisms and its physical environment.

Emissions: The release of substances (e.g., greenhouse gases) into the atmosphere. Emission calculations within the calculator are represented as a single currency: carbon dioxide equivalents (CO₂e) i.e. CH₄ís impact as a greenhouse gas is 23 times greater than CO₂, whilst N₂Oís impact nearly 300 times that of CO₂. These differences are taken into account when calculating CO₂e emissions for your farming enterprise.

Enhanced Greenhouse Effect: The increase in the natural greenhouse effect resulting from increases in atmospheric concentrations of GHGs due to emissions from human activities.

General Circulation Model (GCM): A computer model of the basic dynamics and physics of the components of the global climate system (including the atmosphere and oceans) and their interactions which can be used to simulate climate variability and change.

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 Potential (GWP): A system of multipliers devised to enable warming effects of different gases to be compared. The cumulative warming effect, over a specified time period, of an emission of a mass unit of CO₂ is assigned the value of 1. Effects of emissions of a mass unit of non-CO₂ greenhouse gases are estimated as multiples. For example, over the next 100 years, a gram of methane (CH4) in the atmosphere is currently estimated as having 23 times the warming effect as a gram of carbon dioxide; methane's 100-year GWP is thus 23. Estimates of GWP vary depending on the time-scale considered (e.g., 20-, 50-, or 100-year GWP), because the effects of some GHGs are more persistent than others.

Greenhouse Effect: The insulating effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature about 60ìF warmer than it would be otherwise.

Greenhouse Gas (GHG): Any gas that contributes to the "greenhouse effect."

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 (see "Second Assessment Report" and "Third Assessment Report").

Land Use, Land-Use Change and Forestry (LULUCF): Land uses and land-use changes can act either as sinks or as emission sources. It is estimated that approximately one-fifth of global emissions result from LULUCF activities. The Kyoto Protocol allows Parties to receive emissions credit for certain LULUCF activities that reduce net emissions.

Methane (CH₄): CH₄ is among the six greenhouse gases to be curbed under the Kyoto Protocol. Atmospheric CH₄ is produced by natural processes, but there are also substantial emissions from human activities such as landfills, livestock and livestock wastes, natural gas and petroleum systems, coalmines, rice fields, and wastewater treatment. CH₄ has a relatively short atmospheric lifetime of approximately 10 years, but its 100-year GWP is currently estimated to be approximately 23 times that of CO₂.

Negative Feedback: A process that results in a reduction in the response of a system to an external influence. For example, increased plant productivity in response to global warming would be a negative feedback on warming, because the additional growth would act as a sink CO₂, reducing the atmospheric CO₂ concentration.

Nitrous oxide (N₂O): N₂O is among the six greenhouse gases to be curbed under the Kyoto Protocol. N₂O is produced by natural processes, but there are also substantial emissions from human activities such as agriculture (when adding nitrogen sources and fertilizers to soil) and fossil fuel combustion. The atmospheric lifetime of N₂O is approximately 100 years, and its 100-year GWP is currently estimated to be 296 times that of CO₂.

ppm or ppb: Abbreviations for ìparts per millionî and ìparts per billion,î 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.

Radiative Forcing: The term radiative forcing refers to changes in the energy balance of the earth-atmosphere system in response to a change in factors such as greenhouse gases, land-use change, or solar radiation. The climate system inherently attempts to balance incoming (e.g., light) and outgoing (e.g. heat) radiation. Positive radiative forcings increase the temperature of the lower atmosphere, which in turn increases temperatures at the Earth's surface. Negative radiative forcings cool the lower atmosphere. Radiative forcing is most commonly measured in units of watts per square meter (W/m2).

Reforestation: Replanting of forests on lands that have recently been harvested.

Renewable Energy: Energy obtained from sources such as geothermal, wind, photovoltaic, solar, and biomass.

Sequestration: Opportunities to remove atmospheric CO₂, either through biological processes (e.g. plants, trees and soil), or geological processes through storage of CO₂ in underground reservoirs.

Sinks: Any process, activity or mechanism that results in the net removal of greenhouse gases, aerosols, or precursors of greenhouse gases from the atmosphere.

Socrates: Soil carbon simulation model, (Grace et al., Soil Biology & Biochemistry, 2006), which has been shown to provide similar estimates of soil C change to the Roth C soil model (Skjemstad et al., RIRDC Report CSO-5A,1996).

Soil: The decomposition of soil organic matter, crop residues and stubbles is dependent on soil moisture, with a tendency for more water to be retained for longer in soils with higher clay content.

Source: Any process or activity that results in the net release of greenhouse gases, aerosols, or precursors of greenhouse gases into the atmosphere.

Texture: Soils with a higher clay content tend to accumulate carbon in greater amounts compared to sandier soils.

Trace Gas: A term used to refer to gases found in the Earthís atmosphere other than nitrogen, oxygen, argon and water vapor. When this terminology is used, carbon dioxide, methane, and nitrous oxide are classified as trace gases. Although trace gases taken together make up less than one percent of the atmosphere, carbon dioxide, methane and nitrous oxide are important in the climate system. Water vapor also plays an important role in the climate system; its concentrations in the lower atmosphere vary considerably from essentially zero in cold dry air masses to perhaps 4 percent by volume in humid tropical air masses.

UN Framework Convention on Climate Change: (UNFCCC) A treaty signed at the 1992 Earth Summit in Rio de Janeiro that calls for the ìstabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.î 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.

Uncertainty: Uncertainty is a prominent feature of the benefits and costs of climate change. Decision makers need to compare risk of premature or unnecessary actions with risk of failing to take actions that subsequently prove to be warranted. This is complicated by potential irreversibilities in climate impacts and long term investments.

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