Climate Change 2007: The Physical Science Basis

According to the Intergovernmental Panel on Climate Change (IPCC) the climate crisis is being caused by to many greenhouse gases in the atmosphere. The main three contributors being carbon dioxide, methane, and nitrous oxide. "The global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 ppm to 379 ppm in 2005." The main carbon emitter is a result of worldwide fossil fuel use in vehicles and industry. "The global atmospheric concentration of methane has increased from a pre-industrial value of about 715 ppb to 1732 ppb in the early 1990s, consistent with total emissions (sum of anthropogenic and natural sources) being nearly constant during this period. It is very likely that the observed increase in methane concentration is due to anthropogenic activities, predominately agriculture and fossil fuel use, but relative contributions from different source types are not well determined." "The global atmospheric nitrous oxide concentration increased from a pre-industrial value of about 270 ppb to 319 ppb in 2005. The growth rate has been approximately constant since 1980. More than a third of all nitrous oxide emissions are anthropogenic and are primarily due to agriculture." These increases have created dramatic changes in the climate already which could accelerate over time. According to the Third Assessment Report (TAR) "leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6[+0.6 to +2.4] W m-2." The highest temperatures ever recorded have been within the last 12 years. This contributes to increased sea level due to melting of glaciers and ice caps. "At continental, regional, and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones." "It is not a projection but defined as the global average surface warming following a doubling of carbon dioxide concentrations. It is likely to be in the range 2 to 4.5 C with a best estimate of about 3 C, and it is very unlikely to be less than 1.5 C." This is the bare facts without any fluffing up aside from the quotations added for to give a summary of the article the majority is scientific data and possible scenarios on how the public will react.

Citations:
Climate Change 2007: The Physical Science Basis by: the Intergovernmental Panel on Climate Change

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