Diferencia entre revisiones de «Calentamiento global»

El '''calentamiento global''' es el aumento a largo plazo de la temperatura media del [[Clima|sistema climático]] de la [[Tierra]]. Es un aspecto primordial del [[cambio climático]] actual, demostrado por la [[registro instrumental de temperaturas|medición directa de la temperatura]] y de varios efectos del calentamiento.<ref name="AR5 WG1 SPM p4">{{Harvnb|IPCC AR5 WG1 Summary for Policymakers|2013|p=4|ps =: Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased}}</ref><ref name="EPA myths">{{Cita web |url=https://www.epa.gov/ghgemissions/myths-vs-facts-denial-petitions-reconsideration-endangerment-and-cause-or-contribute |título=Myths vs. Facts: Denial of Petitions for Reconsideration of the Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act |fecha=25 de agosto de 2016 |editorial=U.S. Environmental Protection Agency |cita=The U.S. Global Change Research Program, the National Academy of Sciences, and the Intergovernmental Panel on Climate Change (IPCC) have each independently concluded that warming of the climate system in recent decades is "unequivocal". This conclusion is not drawn from any one source of data but is based on multiple lines of evidence, including three worldwide temperature datasets showing nearly identical warming trends as well as numerous other independent indicators of global warming (e.g. rising sea levels, shrinking Arctic sea ice). |access-date=7 de agosto de 2017}}</ref>

Los términos ''calentamiento global'' y ''cambio climático'' a menudo se usan indistintamente,<ref name="Shaftel 2016">{{Harvnb|Shaftel|2016|p=}}: "{{thinsp}}'Climate change' and 'global warming' are often used interchangeably but have distinct meanings. … Global warming refers to the upward temperature trend across the entire Earth since the early 20th century … Climate change refers to a broad range of global phenomena … [which] include the increased temperature trends described by global warming."</ref> pero de forma más precisa ''calentamiento global'' es el incremento global en las temperaturas de superficie y su aumento proyectado causado predominantemente por actividades humanas (antrópico),<ref name="AR5 Glossary GW">{{harvnb|IPCC AR5 SYR Glossary|2014|page=124 |ps =: Global warming refers to the gradual increase, observed or projected, in global surface temperature, as one of the consequences of radiative forcing caused by anthropogenic emissions. }}; {{harvnb|IPCC SR15 Ch1|2018|p=51}}: "Global warming is defined in this report as an increase in [[Global surface temperature|combined surface air and sea surface temperatures]] averaged over the globe and over a 30-year period. Unless otherwise specified, warming is expressed relative to the period 1850–1900, used as an approximation of pre-industrial temperatures in AR5.".</ref> mientras que ''cambio climático'' incluye tanto el calentamiento global como sus efectos en el clima.<ref>{{Harvnb|Shaftel|2016|p=}}; {{harvnb|Associated Press, 22 September|2015}}: "The terms global warming and climate change can be used interchangeably. Climate change is more accurate scientifically to describe the various effects of greenhouse gases on the world because it includes extreme weather, storms and changes in rainfall patterns, ocean acidification and sea level.".</ref> Si bien ha habido periodos prehistóricos de calentamiento global,<ref name="AR5 WG1 Ch 5">{{harvnb|IPCC AR5 WG1 Ch5|2013|pages=389, 399–400|ps =: "5: Information from Paleoclimate Archives: The [[Paleocene–Eocene Thermal Maximum|PETM]] [around 55.5–55.3 million years ago] was marked by … global warming of 4&nbsp;°C to 7&nbsp;°C ..... [[Deglaciation|Deglacial]] global warming occurred in two main steps from 17.5 to 14.5 ka [thousand years ago] and 13.0 to 10.0 ka.}}</ref> varios de los cambios observados desde mediados del siglo XX no han tenido precedentes desde décadas a milenios.<ref name="AR5 WG1 SPM p4" /><ref name="SYR SPM 1.1">{{harvnb|IPCC AR5 SYR Summary for Policymakers|2014|p=2|ps =: SPM 1.1 .... Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. The period from 1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere, where such assessment is possible (medium confidence).}}</ref>