Glossary
This listing is by no means complete or comprehensive, but I have tried to include most of the terms that crop up in articles on climate change. Any errors that may have crept in during the simplification process are entirely my own--G J Lau.
Acidification: As the oceans absorb carbon dioxide from the atmosphere, the water becomes more acid. This reduces the supply of calcium carbonate, which corals and other marine life need to build their structures.
Aerosol: Airborne solid or liquid particles in the atmosphere. Aerosols scatter and absorb radiation and help make clouds. Their effect on global warming is still being explored.
Anthropogenic: Anything that is the result of human activity, specifically in this context the levels of carbon dioxide and other greenhouse gases.
Carbon Dioxide (CO2): CO2 is a normal part of the ambient air. Burning fossil fuels and deforestation have increased atmospheric concentrations of CO2 by approximately 30 percent since the industrial revolution.
Climate: Climate is weather looked at over a long period of time, usually a minimum of 30 years.
Climate Change: Any change in climate over time, whether due to natural variability or as a result of human activity.
Climate Model: A numerical representation of the climate system that is used to study climate characteristics.
Climate (Change) Scenario: A climate scenario consists of projections of possible climate futures, containing developments of driving forces, greenhouse gas emissions, temperature change and sea level rise and their key relationships. A climate change scenario is the difference between a climate scenario and the current climate.
Emissions: The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere.
Forcing Mechanism: Any process that alters the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. Such mechanisms include changes in light output from the sun, volcanic eruptions, and enhancement of the natural greenhouse effect by emissions of greenhouse gases.
Global Warming: The progressive gradual rise of the Earth's average surface temperature as compared to pre-industrial times.
Global Warming Potential (GWP): A system of multipliers devised to enable warming effects of different gases to be compared using CO2 as a base. 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.
Greenhouse Effect: The insulating effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature warmer than it would be otherwise. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase.
Greenhouse Gas (GHG): Any gas that absorbs infrared radiation in the atmosphere. 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).
Infrared Radiation: Radiation emitted by the Earth's surface, the atmosphere and the clouds.
Methane (CH4): 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 (see above) is currently estimated to be approximately 23 times that of CO2.
Multiplier: The result of Force A acting on and intensifying the consequences of Event B. Example: Climate change acts as a national security threat multiplier.
Positive Feedback: The outcome of a process that increases the response of a system to an external influence. For example, increased atmospheric water vapor in response to global warming would be a positive feedback on warming, because water vapor is a GHG.
PPM or PPB: Abbreviations for "parts per million" and "parts per billion" - the units in which concentrations of greenhouse gases are commonly presented. Since the pre-industrial era, atmospheric concentrations of carbon dioxide have increased from 270 ppm to 370 ppm.
Sulfate Aerosols: Particulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the atmosphere. Sulfate aerosols are injected into the atmosphere from the combustion of fossil fuels and the eruption of volcanoes like Mt. Pinatubo. Recent theory suggests that sulfate aerosols may lower the Earth's temperature by reflecting away solar radiation (negative radiative forcing).
Weather: Atmospheric condition at any given time or place. 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.
Sources:
U. S. Environmental Protection Agency
California Climate Change Portal
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