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Anthropogenic greenhouse gases
Anthropogenic greenhouse gases
The concentrations of several greenhouse gases have increased over time. Human
activity increases the greenhouse effect primarily through release of carbon
dioxide, but human influences on other greenhouse gases can also be important.
Some of the main sources of greenhouse gases due to human activity include:
* burning of fossil fuels and deforestation leading to higher carbon dioxide
concentrations;
* livestock and paddy rice farming, land use and wetland changes, pipeline
losses, and covered vented landfill emissions leading to higher methane
atmospheric concentrations. Many of the newer style fully vented septic systems
that enhance and target the fermentation process also are major sources of
atmospheric methane;
* use of chlorofluorocarbons (CFCs) in refrigeration systems, and use of CFCs
and halons in fire suppression systems and manufacturing processes.
* agricultural activities, including the use of fertilizers, that lead to higher
nitrous oxide concentrations.
Greenhouse gas emissions from industry, transportation and agriculture are very
likely the main cause of recently observed global warming..
Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gasses
(but not CFCs, because CFCs are controlled by the Montreal Protocol) are the
greenhouse gases and the subject of the Kyoto Protocol, which entered into force
in 2005. CFCs are controlled by the Montreal Protocol, motivated by their effect
on stratospheric ozone rather than by their effect on greenhouse warming. Note
that ozone depletion has only a minor role in greenhouse warming though the two
processes often are confused.
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