Climate Change Definitions & GlossariesClimate Change or Global Warming: These two terms tend to be used interchangeably, and can be defined as variability in climate (precipitation, temperature, wind patterns), usually in a global context and usually long-term. Most commonly, the phrases are used in reference to human-caused change in climate that is resulting in a warming of the earth's average surface temperature beyond any natural cycle. The major cause of most of the warming is rising carbon dioxide levels in the atmosphere, created when fossil fuels are burned (the human-cause). Greenhouse Effect: This is a natural system of the planet, which maintains the earth's average global temperature at 15 degrees Celsius. It is caused by the presence of water vapour and other gases in the atmosphere, which allows incoming solar energy to pass through to the earth's surface, yet traps some of the outgoing radiation as it is reflected back from the earth's surface. The gases in the atmosphere act as an insulating layer, much like the way glass panes or plastic acts to capture heat in a greenhouse, hence the phenomenon is called the "greenhouse effect". The heart of the climate change problem is a change in this phenomenon. Human activities (primarily the burning of fossil fuels) are causing the concentration of some types of these gases to increase in the atmosphere, and to produce more greenhouse gases than can be absorbed through the earth's natural system. The earth's carbon sinks (the places that carbon can be absorbed) are saturated. This global carbon cycle which, over time, had reached a natural balance of carbon sources and sinks or reservoirs, has become disrupted. These increased concentrations of gases are trapping more heat energy, accelerating the greenhouse effect and causing increased variability in the climate. Greenhouse Gases: Any gas that contributes to the "greenhouse effect" and absorbs the sun's infrared radiation is considered a greenhouse gas. The most abundant greenhouse gas is actually the water present in the atmosphere in a gaseous form. Other greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3 ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Canadians are the second highest greenhouse gas producers per capita, second only to the United States, although we produce only 2.5 percent of total global emissions. The principal greenhouse gas contributor to the enhanced greenhouse effect is carbon dioxide. It is released in the greatest amounts and represents approximately 50% of the warming attributed to greenhouse gases. Carbon dioxide is produced by the burning of fossil fuels such as coal, oil and natural gas for electricity, transportation and heating. Methane 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. Nitrous oxide, produced from agriculture and fossil fuel combustion, is also of concern. Each greenhouse gas is different in how much it traps heat. To compare greenhouse gases, they are indexed according to their Global Warming Potential (GWP). GWP is the ability of a greenhouse gas to trap heat in the atmosphere relative to an equal amount of carbon dioxide. Carbon dioxide assumes the value one (1). Carbon dioxide, though the most prevalent, is the least powerful greenhouse gas. Many other greenhouse gases trap heat far more powerfully than CO2, some of them tens of thousands of times more powerfully. For example, methane is 21 times more powerful a greenhouse gas than CO2. Kyoto Protocol: Canada is a signatory to many international environmental agreements and protocols. The Kyoto Protocol is an international agreement that was adopted in 1997 in Kyoto, Japan. The Protocol sets binding emission targets for developed countries that would reduce their greenhouse gas emissions on average 6 percent below 1990 levels by 2008-2012. Over 150 countries, including Canada, Japan, Russia, and many other industrialized nations signed on to the Kyoto agreement, and Canada formally ratified it in December, 2002. It went into effect in February, 2005. Koto has been controversial since its adoption with the absence of the US as a signatory seen as a major criticism. The likelihood of Canada achieving its targets by 2012 now seems slim (by 2004, greenhouse gas emissions had increased by 27% over 1990 levels). However, it is generally recognized that the emission reduction targets assigned by the Kyoto Protocol will not reduce the problem of global warming significantly - they are only a first step. Scientific evidence indicates that to combat climate change, greenhouse gas emissions will have to be cut by more than 50 percent from 1990 levels by the end of this century. Climate Change Mitigation: These are activities, actions, or measures that prevent or reduce the release of greenhouse gases emissions that are of human origin or within human control (examples are switching to renewable fuels, using energy-efficient equipment, and conserving energy by turning off equipment). Climate Change Adaptation: Climate change is already underway, so in addition to reducing our emissions to reduce climate change impacts, we need to prepare for the impacts that global warming may bring. Climate change adaptation measures are implemented to reduce adverse consequences of climate change and to enhance positive impacts (examples are coastal protection strategies, altering planting patterns and forest management practices)
Pew Center Glossary of Climate Change US Environmental Protection Agency - Glossary of Climate Change Terms Environment Canada Green Lane: Glossary Sila: Clue into Climate Change Glossary (Canadian Museum of Natural History) |