Escalfamiento global

De Biquipedia
Ir ta: navego, busca
Articlo d'os 1000
A temperatura meyana d'a superficie global entre os anyos 1961 y 1990.
Temperatura meyana d'a superficie entre 1995 e 2004 respecto a lo periodo entre 1940 y 1980.

O escalfamiento global ye o proceso d'aumento gradual d'a temperatura d'a planeta Tierra por, entre atras causas, a intensificación d'o efecto hibernadero.[1] O Grupo Intergubernamental sobre o Cambeyo Climatico (IPCC) diz que gran parti de l'aumento dende meyatos d'o sieglo XX se debe a l'aumento de concentracions antropochenicas de gas hibernadero.[2] Probablement fenomens naturals como a variación solar y os vulcans provocoron una mica d'escalfamiento global dende a epoca preindustrial dica 1950 y un chicot enfriamiento dende 1950 entabant.[3][4] Istas conclusions basicas han estato aprebatas por, como minimo, 30 sociedatz y academias scientificas,[5] incluyendo totas as academias nacionals de sciencia d'os países más industrializatos.[6][7][8] Mientres que bells scientificos individuals han amostrato desalcuerdo con ista hipotesi,[9] a gran mayoría de scientificos que treballan en o cambeyo climatico son d'alcuerdo con as conclusions prencipals d'o IPCC.[10][11]

Procheccions de modelos climaticos indican que as temperaturas d'a superficie puyarán d'1,1 a 6,6 °C mientres o sieglo XXI.[2] O más incierto en ista estimación ye l'aumento u no d'emisions de gas hibernadero y l'uso de modelos con una sensibilidat climatica diferent. Una atra cosa incierta ye como o escalfamiento y altros cambeyos relacionatos variaran en cada rechión. A mayoría d'os estudeyos se centran en o periodo dimpués d'o 2100, y se creye que o escalfamiento continará bells mil anyos si os rans de gas hibernadero s'estabilizan. Isto se debe a la gran capacidat de calor d'os ocians.[2]

L'aumento d'a temperatura global prevocará a puyata d'o ran d'as mars y cambeará o numero de precipitacions, incluindo una expansión d'as rechions subtropicals deserticas.[12] Atros efectos incluyen l'aumento en a intensidat d'o clima estremo, cambeyos en as cullitas, modificacions d'as rotas comercials, o retacule d'as cheleras y a estinción d'especies.

A mayoría d'os gubiernos han sinyato y ratificato lo Protocolo de Kyoto ta reducir as emisions de gas hibernadero.

Referencias[editar | editar código]

  1. (ca) Enciclopèdia Catalana
  2. 2,0 2,1 2,2 Summary for PolicymakerFis. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.Intergovernmental Panel on Climate Change
  3. Understanding and Attributing Climate Change. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental Panel on Climate Change. Hegerl, Gabriele C. et al. "Recent estimates (Figure 9.9) indicate a relatively small combined effect of natural forcings on the global mean temperature evolution of the seconds half of the twentieth century, with a small net cooling from the combined effects of solar and volcanic forcings"
  4. Ammann, Caspar. et al., Solar influence on climate during the past millennium: Results from ransient simulations with the NCAR Climate Simulation Model.Proceedings of the National Academy of Sciences of the United States of America. "However, because of a lack of interactive ozone, the model cannot fully simulate features discussed in (44)." "While the NH temperatures of the high-scaled experiment are often colder than the lower bound from proxy data, the modeled decadal-scale NH surface temperature for the medium-scaled case falls within the uncertainty range of the available temperature reconstructions. The medium-scaled simulation also broadly reproduces the main features seen in the proxy records." "Without anthropogenic forcing, the 20th century warming is small. The simulations with only natural forcing components included yield an early 20th century peak warming of ≈0.2 °C (≈1950 AD), which is reduced to about half by the end of the century because of increased volcanism"
  5. En 2001 se sinyó por as academias scientificas d'Australia, Belchica, Brasil, Canadá, o Caribe, China, Francia, Alemanya, India, Indonesia, Irlanda, Italia, Malaisia, Nueva Zelanda, Suecia y o Reino Unito. En 2005 tamién se i adhibioron Chapón, Rusia y os Estatos Unitos. En 2007 se i adhibioron Mexico y Surafrica.
  6. The Science Of Climate Change, Royal Society
  7. Joint science academies' statement: Global response to climate change, Royal Society
  8. Joint science academies' statement on growth and responsibility: sustainability, energy efficiency and climate protection, Potsdam Institute for Climate Impact Research
  9. Don't fight, adapt. National Post
  10. A guide to facts and fictions about climate change. Royal Society. "However, the overwhelming majority of scientists who work on climate change agree on the main points"
  11. Beyond the Ivory Tower: The Scientific Consensus on Climate Change. Science Magazine
  12. [http://www.atmos.berkeley.edu/~jchiang/Class/Spr07/Geog257/Week10/Lu_Hadley06.pdf Lu, Jian; Gabriel A. Vecchi; Thomas Reichler: Expansion of the Hadley cell under global warming. Geophysical Research Letters