Încălzirea globală
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Cresterea temperaturii medii in anii 1995 - 2005 faţă de media anilor 1940 - 1980.
Încălzirea globală se referă la creşterea temperaturii medii a Pământului în atmosfera de joasă altitudine şi în oceane începând cu mijlocul sec. XX. Conform celui de Al patrulea Raport de Evaluare al Comitetului Interguvernamental pentru Schimbări Climatice (CISC) al ONU din 2007, temperatura globală la suprafaţa Pământului a crescut cu 0,74 ± 0.18 °C în sec. XX.[2][A] Cele mai multe din măsurătorile de temperatură au arătat că creşterea temperaturii începând cu mijlocul sec. XX este un rezultat al creşterii concentraţiilor de gaze care produc efectul de seră ca urmare a activităţii umane, precum arderea combustibilului fosil şi despăduririle.[3]Opacizarea globală, rezultatul concentraţiilor de aerosoli în atmosferă care blochează lumina soarelui, a anulat parţial efectele încălzirii induse de efectul de seră.
Proiecţiile modelului climatic rezumat în ultimul raport CISC indică faptul că temperatura globală la suprafaţă pare să crească cu 1,1 până la 6,4 °C în sec. XXI.[2] Incertitudinea în această estimare provine din folosirea modelelor cu diferite sensitivităţi climaterice faţă de concentraţiile de gaz care produc efectul de seră, şi folosirea de estimări diferite privind evoluţia emisiilor de gaze care produc efectul de seră. O creştere a temperaturii globale va duce la o creştere a nivelului mărilor şi va schimba cantitatea şi reţeaua de precipitaţii, incluzând probabil expansiunea deşertelor subtropicale.[4] Este de aşteptat ca încălzirea să fie cea mai mare în zona arctică, şi să fie asociată cu continuarea retragerii gheţarilor, a solului criotic şi a banchizelor. Alte efecte posibile includ schimbări ale frecvenţei şi intensităţii evenimentelor meteorologice extreme, dispariţia unor specii, şi schimbări ale producţiilor agricole. Încălzirea şi alte schimbări conexe vor varia de la regiune la regiune, necunoscându-se încă natura acestor schimbări reginale.[5] Ca rezultat al creşterii actuale a bioxidului de carbon în atmosferă, oceanele au devenit mai acide, şi se estimează că acest efect va continua.[6][7]
Evoluţia temperaturilor medii anuale şi a mediilor pe cinci ani în epoca industrializării.
Există un consens ştiinţific în existenţa unei încălziri globale antropogenice, datorate omului.[8][9][10][B] Dar există dezbateri politice şi publice continui pe această temă. Protocolul de la Kyoto intenţiona să stabilizeze concentraţia de gaz care produce efectul de seră pentru a preveni o "interferenţă antropogenică periculoasă".[11] În noiembrie 2009, 187 state au semnat şi ratificat protocolul.[12]
Măsurile propuse împotriva schimbărilor climaterice includ atenuarea acesteia prin reducerea emisiilor, adaptarea la efectele încălzirii globale, şi dezvoltarea eoingineriei pentru a îndepărta gazeşe care produc efectul de seră din atmosferă sau care blochează lumina solară.
Note
- ^ Creşterea este pentru perioada 1905 - 2005. Temperatura de suprafaţă globală este definită de Al patrulea Raport de Evaluare al Comitetului Interguvernamental pentru Schimbări Climatice ca temperatura medie a aerului de la suprafaţa Pământului din zona de uscat şi temperatura suprafeţei apei mărilor. Estimările se găsesc într-un interval de încredere de 90%.
- ^ Acordul din 2001 a fost semnat de academiile naţionale de ştiinţă din Australia, Belgia, Brazilia, Canada, Caraibe, China, FranţA, Germania, India, Indonezia, Irlanda, Italia, Malaiezia, Noua Zeelandă, Suedia, şi Marea Britanie. La acordul din 2005 au mai aderat Japonia, Rusia, şi Statele Unite. În 2007 au mai aderat Mexic şi Africa de Sud. Reţeaua Academiilor de Ştiinţă din Africa şi Academia de Ştiinţă din Polonia au semnat cu observaţii.
Referinţe
- ^ 2009 Ends Warmest Decade on Record. NASA Earth Observatory Image of the Day, January 22, 2010.
- ^ a b c IPCC (2007-05-04). "Summary for Policymakers" (PDF). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.
- ^ "Understanding and Responding to Climate Change". United States National Academy of Sciences. 2008. "Most scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere."
- ^ Lu, Jian; Vecchi, Gabriel A.; Reichler, Thomas (2007). "Expansion of the Hadley cell under global warming" (PDF). Geophysical Research Letters 34: L06805. doi:10.1029/2006GL028443.
- ^ IPCC (2007) (Full free text). Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. Geneva, Switzerland: IPCC.
- ^ "Future Ocean Acidification". Climate Change Science. U.S. EPA. 2010-08-20.
- ^ "What is Ocean Acidification?". Pmel.noaa.gov.
- ^ Oreskes, Naomi (December 2004). "BEYOND THE IVORY TOWER: The Scientific Consensus on Climate Change". Science 306 (5702): 1686. doi:10.1126/science.1103618. PMID 15576594. "Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case. [...] Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect."
- ^ "Joint Science Academies' Statement" (PDF).
- ^ "Understanding and Responding to Climate Change" (PDF).
- ^ "Article 2". The United Nations Framework Convention on Climate Change. "Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner"
- ^ "Kyoto Protocol: Status of Ratification" (PDF). United Nations Framework Convention on Climate Change. 2009-01-14.
Bibliografie
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- Hinrichs, Kai-Uwe; Hmelo, Laura R.; Sylva, Sean P. (2003-02-21). "Molecular Fossil Record of Elevated Methane Levels in Late Pleistocene Coastal Waters". Science 299 (5610): 1214–1217. doi:10.1126/science.1079601. PMID 12595688.
- Hirsch, Tim (2006-01-11). "Plants revealed as methane source". BBC.
- Hoyt, Douglas V.; Schatten, Kenneth H. (1993–11). "A discussion of plausible solar irradiance variations, 1700–1992". Journal of Geophysical Research 98 (A11): 18,895–18,906. doi:10.1029/93JA01944.
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- Karnaukhov, A. V. (2001). "Role of the Biosphere in the Formation of the Earth’s Climate: The Greenhouse Catastrophe" (PDF). Biophysics 46 (6).
- Kenneth, James P.; et al. (2003-02-14). Methane Hydrates in Quaternary Climate Change: The Clathrate Gun Hypothesis. American Geophysical Union.
- Keppler, Frank; et al. (2006-01-18). "Global Warming – The Blame Is not with the Plants". Max Planck Society.
- Lean, Judith L.; Wang, Y.M.; Sheeley, N.R. (2002–12). "The effect of increasing solar activity on the Sun's total and open magnetic flux during multiple cycles: Implications for solar forcing of climate" (abstract). Geophysical Research Letters 29 (24): 2224. doi:10.1029/2002GL015880.
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Linkuri
Cercetare
- Intergovernmental Panel on Climate Change — collection of IPCC reports
- NASA Goddard Institute for Space Studies - Global change research
- United States Global Change Research Program - Global climate change research in the United States
- Climate Change at the National Academies — repository for reports
- Nature Reports Climate Change — free-access web resource
- Met Office: Climate change — UK National Weather Service
- Global Science and Technology Sources on the Internet — extensive commented list of internet resources
- Educational Global Climate Modelling (EdGCM) — research-quality climate change simulator
- DISCOVER — satellite-based ocean and climate data since 1979 from NASA
- Global Warming Art — collection of figures and images
Educaţie
- What Is Global Warming? — by National Geographic
- Global Climate Change Indicators - from NOAA
- NOAA Climate Services - from NOAA
- Global Warming Frequently Asked Questions — from NOAA
- Understanding Climate Change – Frequently Asked Questions — from UCAR
- Global Climate Change: NASA's Eyes on the Earth — from NASA's JPL and Caltech
- OurWorld 2.0 — from the United Nations University
- Pew Center on Global Climate Change — business and politics
- Best Effort Global Warming Trajectories – Wolfram Demonstrations Project — by Harvey Lam
- Koshland Science Museum – Global Warming Facts and Our Future — graphical introduction from National Academy of Sciences
- The Discovery of Global Warming – A History — by Spencer R. Weart from The American Institute of Physics
- Climate Change: Coral Reefs on the Edge — A video presentation by Prof. Ove Hoegh-Guldberg, University of Auckland
- Climate Change Indicators in the United States Report by United States Environmental Protection Agency, 80 pp.
- Global Warming
Acest articol conţine materiale traduse şi adaptate din Wikipedia de Nicolae Sfetcu sub licenţă gratuită GNU.
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