Changes

'''Global warming''' is the term ascribed to an increase in global average surface temperature. The global average surface temperature warmed about 0.8 K during the last century <ref>[http://data.giss.nasa.gov/gistemp/2005/ GISS Surface Temperature Analysis]</ref><ref>Jones, P. D., M. New, D. E. Parker, S. Martin, and I. G. Rigor (1999), Surface air temperature and its changes over the past 150 years, Rev. Geophys., 37(2), 173–200.</ref>, and scientists say the warming is caused by increases in carbon dioxide and other greenhouse gases in the atmosphere.<ref>[http://www.sciencemag.org/cgi/reprint/306/5702/1686.pdf The Scientific Consensus on Climate Change]</ref> The possibility of adverse consequences has become a major concern for environmentalists. Some scientists such as [[Richard Lindzen]], [[Fred Singer]], etc., say that the patterns of global warming are naturally caused.  

'''Global warming''' is the term ascribed to an increase in global average surface temperature. The global average surface temperature warmed about 0.8 K during the last century <ref>[http://data.giss.nasa.gov/gistemp/2005/ GISS Surface Temperature Analysis]</ref><ref>Jones, P. D., M. New, D. E. Parker, S. Martin, and I. G. Rigor (1999), Surface air temperature and its changes over the past 150 years, Rev. Geophys., 37(2), 173–200.</ref>, and scientists say the warming is caused by increases in carbon dioxide and other greenhouse gases in the atmosphere.<ref>[http://www.sciencemag.org/cgi/reprint/306/5702/1686.pdf The Scientific Consensus on Climate Change]</ref> The possibility of adverse consequences has become a major concern for environmentalists. Some scientists such as [[Richard Lindzen]], [[Fred Singer]], etc., say that the patterns of global warming are naturally caused.  

Politicians who support the [[Kyoto Protocol]] have made the claim that there is a cause and effect relationship between increases in atmospheric concentrations of [[greenhouse gases]] and air temperature.

Politicians who support the [[Kyoto Protocol]] have made the claim that there is a cause and effect relationship between increases in atmospheric concentrations of [[greenhouse gas]]es and air temperature.

==Natural variability of the climate system==

==Natural variability of the climate system==