Canjin yanayi, Ya haɗa da dumamar yanayi, Wanda hayakin dan Adam na iskar gas, da kuma sauye-sauye masu yawa na yanayi.[1] Koda yake canjin yanayi ya gabata a baya, Tun daga tsakiyar ƙarni na ashirin 20, Yawan girman tasirin ɗan Adam, kan tsarin yanayi na duniya da kuma girman tasirin wannan tsarin ba a taba yin irin sa ba.[2]

Canjin yanayi
atmospheric phenomenon (en) Fassara, Abubuwan da suka shafi muhalli da human impact on the environment (en) Fassara
Bayanai
Ƙaramin ɓangare na external risk (en) Fassara da global climate change (en) Fassara
Has cause (en) Fassara carbon dioxide emissions (en) Fassara, greenhouse gas emissions (en) Fassara, hayakin da ake fitarwa daga noma da Gandun daji
Karatun ta Climatology
Contributing factor of (en) Fassara arctic sea ice decline (en) Fassara
Described at URL (en) Fassara ipcc.ch
Has contributing factor (en) Fassara coal-fired power station (en) Fassara
Handled, mitigated, or managed by (en) Fassara Daidaituwar canjin yanayi
WordLift URL (en) Fassara http://data.thenextweb.com/tnw/entity/global_warming
Hannun riga da global cooling (en) Fassara
Matsakaicin yanayin duniya daga shekara ta 2010 zuwa shekarar 2019 idan aka kwatanta da matsakaicin matakin farko daga shekara ta 1951 zuwa shekarata 1978 (Tushe). NASA)
hoton yanayin canji yanayi

Canjin, yanayi; Ɗan adam ya haifar da canjin yanayi ba wata ƙungiyar kimiyya ta ƙasa ko ta ƙasa ke jayayya ba.[3] Babban direba shine fitarwa na iskar gas, Wanda kuma sama da 90% shine carbon dioxide wato (Sinadari) (CO2) da methane (gas wanda bashi da kala ko kamshi).[4] Kone burbushin mai don amfani da makamashi shine asalin tushen fitar da wannan hayaƙin, tare da kuma ƙarin gudummawa daga harkar noma, sare bishiyoyi, da kuma matakan masana'antu.[5] Hawan zafin jiki yana haɓaka ko zafin rai ta hanyar bayanin yanayi, kamar asarar dusar ƙanƙara mai nuna hasken rana da murfin kankara, ƙarar tururin ruwa (iskar gas mai ɗari da kanta), da canje-canjen zuwa ƙasa da tekun.

Abubuwan da aka lura daga NASA a kan matsakaiciyar 1850-1900 azaman asalin masana'antun farko. Babban direba don haɓaka yanayin duniya a zamanin masana'antu shi ne Kuma ayyukan ɗan adam, tare da ƙarfin halitta yana ƙara bambancin.[6]
Sauyin yanayi a wajen teku

Saboda yanayin sararin samaniya zaiyi zafi fiye da na teku, hamada tana faɗaɗa kuma zafi da wutar daji sun fi zama ruwan dare.[7] Hawan zafin sararin samaniya ya fi girma a cikin Arctic (waje mai tsananin sanyi), inda ya ba da gudummawa ga narkewar dusar ƙanƙara, da kuma komawar kankara da kankara a teku.[8] Yawan kuzarin yanayi da ƙimar kuzarin yanayi suna haifar da guguwa da tsananin yanayi, wanda ke lalata kayayyakin more rayuwa da aikin gona.[9] Ƙaruwar yanayin zafi yana iyakance yawan ruwan teku da kuma illa ga hannayen jari a yawancin sassan duniya.[10] Abubuwan da ake tsammani yanzu da waɗanda ake tsammani daga rashin abinci mai gina jiki, tsananin zafi da cuta sun sa Kungiyar Lafiya ta Duniya ta bayyana canjin yanayi mafi haɗari ga lafiyar duniya a cikin ƙarni na 21.[11] Abubuwan da suka shafi muhalli sun haɗa da ƙarewa ko ƙaura daga yawancin jinsuna yayin da tsarin halittunsu ya canza, mafi akasari nan da nan cikin murjani, dutsen, da Arctic.[12] Ko da kuwa kokarin rage dumamar yanayi na gaba ya yi nasara, wasu tasirin za su ci gaba har tsawon karnoni, gami da hauhawar matakan teku, karuwar yanayin zafi na tekun, da kuma narkon ruwan daga tekun na Sinadarin (CO2).[13]

Yawancin waɗannan tasirin an riga an lura dasu a halin yanzu kuma na zafin jiki, wanda yake kusan 1.1°C (2.0°F) a ma'aunin gwaji.[14] Kungiyar Gwamnati kan Canjin Yanayi (IPCC) ta ba da jerin rahotanni waɗanda ke nuna ƙimar girma a cikin waɗannan tasirin yayin da ɗumamar yanayi ke ci gaba zuwa 1.5°C (2.7°F) a ma'aunin gwaji da kuma bayan.[15] A karkashin yarjejeniyar ta Paris, kasashe sun amince da ci gaba da dumamar yanayi "sosai a karkashin 2.0°C (3.6°F) a ma'aunin gwaji" ta hanyar rage hayaki mai gurbata yanayi. Koyaya, a ƙarƙashin waɗannan alƙawura, ɗumamar yanayi zai kai kimanin 2.8°C (5.0°F) a ma'aunin gwaji a ƙarshen karnin, kuma manufofin yanzu zasu haifar da kusan 3.0°C (5.4°F) a ma'aunin gwaji na dumamar yanayi.[16] Iyakan ɗumamar yanayi zuwa 1.5°C (2.7°F) a ma'aunin gwaji na buƙatar rabin fitar da hayaƙi a cikin 2030, sa'annan ya kai matakin kusan sifili ta 2050.[17].

Yunkurin ragewa ya haɗa da bincike, cigaba, da kuma tura fasahohin masu amfani da makamashi mai kara kuzari, ingantaccen ingancin makamashi, manufofi na rage hayakin mai, burbushin lamura, da kuma adana gandun daji. Fasahar aikin injiniya na yanayi, mafi yawan fitowar hasken rana da kuma cire sanadarin carbon dioxide, suna da iyakantattun abubuwa kuma suna ɗaukar manyan rashin tabbas. Kungiyoyi da gwamnatoci kuma suna aiki don daidaitawa da tasirin ɗumamar yanayi na yanzu da kuma nan gaba ta hanyar ingantaccen kariya ta bakin teku, kyakkyawan kula da bala'i, da haɓaka albarkatun gona masu tsayayya.

Hawan yanayin da aka lura.

gyara sashe
 
Sake sake gina yanayin zafin duniya a cikin karnin da ya gabata ta amfani da bayanan wakili daga zoben itacen, murjani, da kankara a cikin shuɗi.[18] Bayanan kulawa ya kasance daga 1880 zuwa 2019.[19]
 
Bayanin NASA[20] ya nuna cewa yanayin yanayin ƙasa ya karu da sauri fiye da yanayin teku.

Masana da yawa da aka samar da kayan aikin sun nuna cewa tsarin yanayi yana dumama,[21] tun da ga shekarun 2009-2018. kasancewar 0.93 ± 0.07°C (1.67 ± 0.13 ° F) a ma'aunin gwaji ya fi tsarin farko na masana'antu (1850-1900) zafi.[22] A halin yanzu, yanayin zafi yana tashi da kusan 0.2°C (0.36°F) a ma'aunin gwaji a shekaru goma.[23] Tun daga shekarar 1950, adadin ranakun sanyi da dare sun ragu, kuma yawan kwanaki masu dumi da dare sun ƙaru.[24] Abubuwan tarihi na ɗumama da sanyaya, kamar yanayin zamanin da Little Ice Age, basu kasance daidai ba a duk yankuna kamar ɗumamar yanayin yanzu, amma ƙila sun kai yanayin zafi kamar na ƙarshen karni na 20, a cikin iyakokin yankuna.[25] Akwai lokuttan da suka gabata na dumamar yanayi, kamar su Paleocene – Eocene Thermal Maximum.[26] Ko yaya, haɓbakar da aka lura a cikin zafin jiki da CO2 kididdigar yana da sauri har ma abubuwan da suka faru a bayyane waɗanda suka faru a tarihin duniya ba su kusan faruwa yanzu ba.[27]

Rikodin wakili na yanayi ya nuna cewa bambancin yanayi yana daidaita farkon tasirin Juyin Masana'antu, don haka akwai ɗan ƙaramin ɗumamar yanayi tsakanin ƙarni na 18, da tsakiyar karni na 19.[28] Ma'aikatar Gwamnati kan Canjin Yanayi (IPCC) ta karɓi lokacin ƙayyadaddun lokacin aiki zuwa 1850-1900. a matsayin kusancin yanayin zafin duniya na kafin masana'antu,[29] lokacin da rikodin ma'aunin zafi da sanyi ya fara ba da yanayin duniya.[30]

 
Sauyin yanayi a sararin samaniya

Duk da yake ma'aunin dumamar yanayi yana kusa da canjin yanayin zafin yanayi, ana auna waɗannan ma'aunin da nau'ikan sauran abubuwan lura.[31] An sami ƙaruwa a cikin yanayi da ƙarfi na hazo mai yawa, narkewar dusar ƙanƙara da kankara ta ƙasa, da ƙaruwar yanayin yanayi.[32] Fure da fauna suna yin halin da ya dace da ɗumama ɗumi; misali, tsire-tsire suna fure a farkon bazara.[33] Wani mahimmin alama shine sanyaya yanayi na sama, wanda ke nuna cewa iskar gas masu dumama yanayi suna kama zafi a kusa da doron ƙasa kuma suna hana shi watsawa zuwa sararin samaniya.[34]

Koda yake kuma shekaru masu rikodin rikodin suna jawo hankalin manyan kafofin watsa labaru, shekarun mutum ba su da mahimmanci fiye da yanayin yanayin duniya mai tsawo.[35] Misali na gajeriyar matsala shine saurin karuwar yanayin zafin daga 1998, zuwa 2012, wanda aka yiwa lakabi da "dumamar yanayin duniya".[36] A duk tsawon wannan lokacin, ajiyar zafin ruwan teku ya ci gaba da tafiya a hankali zuwa sama, kuma a cikin shekaru masu zuwa, yanayin yanayin ƙasa ya yi sama sama. Za'a iya danganta saurin saurin ɗumamar yanayi da haɗuwa da sauyin yanayi, rage ayyukan hasken rana, da ƙara hasken hasken rana ta abubuwan da ke fitowa daga aman wuta.[37]

Mafita game da canjin yanayi.

gyara sashe

Maganin canjin yanayi Misali, makamashin da ake iya sabuntawa, kamar hasken rana da wutar lantarki, shine mafita daya da ake amfani da ita don rage fitar da hayaki mai gurbata yanayi. Makamashi mai sabuntawa shine ainihin mahimmancin maganin sauyin yanayi. Hanya ce ta samar da wutar lantarki ba tare da fitar da iskar gas ba. Ikon hasken rana babban misali ne na makamashi mai sabuntawa. Masu amfani da hasken rana suna canza hasken rana zuwa wutar lantarki, wanda za'a iya amfani da su don samar da wutar lantarki da gidaje da kasuwanci. Wannan yana rage bukatar wutar lantarki daga tashoshin wutar lantarki da ke kona albarkatun mai, kamar gawayin kwal da iskar gas. Ikon hasken rana shine tushen makamashi mai tsabta da sabuntawa. Hakanan yana ƙara samun araha yayin da fasahar ke inganta.


Bambancicakjini.

gyara sashe

Dumamar yanayi na nufin matsakaita na duniya, tare da yawan ɗumamar yanayi ta bambanta da yanki. Abubuwan da ke sanya ɗumi-dumi ba su da 'yanci daga wuraren da hayaƙin haya ke gurɓata, saboda iskar gas ɗin ta daɗe sosai don yaɗuwa a duniya; Koyaya, baƙar adibas da aka saka a kan dusar ƙanƙara da kankara suna taimakawa dumamar yanayi.

Tun kafin lokacin masana'antu, matsakaiciyar yanayin duniya ya karu kusan ninki biyu kamar na yanayin duniya.[38] Hakan ya faru ne saboda girman karfin zafi na tekuna, kuma saboda tekuna suna rasa karin zafi ta hanyar danshin.[39] Fiye da kashi 90% na ƙarin makamashi a cikin tsarin yanayi a cikin shekaru 50, da suka gabata an adana su a cikin teku, suna dumama da shi.[40] Ragowar ƙarin makamashin ya narkar da kankara kuma ya dumi nahiyoyi da yanayi.[41] Hawan zafi a cikin teku yana haifar da fadada yanayin zafi wanda ya ba da gudummawa ga lura da haɓakar tekun.[42]

Yankin Arewa da pole na Arewa sun dumamau da sauri fiye da pole na Kudu da Kudancin Kudu. Yankin Arewacin duniya ba wai kawai yana da yanki mai yawa ba, har ma yana da yankin dusar kankara da kankara a teku, saboda yadda aka tsara dimbin mutanen da ke kewayen Tekun Arctic. Yayinda wadannan saman suke jujjuyawa daga nuna haske da yawa zuwa duhu bayan kankara ta narke, sai su fara daukar wutar da zafi. Hasashen Kudancin duniya sun riga sun sami ɗan kankara a lokacin bazara kafin ta fara ɗumi.[43] Yanayin Yankin Arctic ya karu kuma ana hasashen zai ci gaba da karuwa a wannan karnin sama da sau biyu na sauran kasashen duniya.[44] Narkewar kankara da katifun kankara a cikin Arctic ya lalata zirga-zirgar teku, gami da raunin Ruwan Tekun, yana haifar da karin dumamar yanayi a wasu yankuna.[45].

Direbobin motsa jiki na canjin yanayi na kwanan nan.

gyara sashe
 
Adiarfafawa daga wasu masu ba da gudummawa ga canjin yanayi a cikin 2011, kamar yadda aka ruwaito a cikin rahoton ƙimar IPCC na biyar

Da kanta, tsarin yanayi yana fuskantar wasu zagaye daban-daban waɗanda zasu iya ɗaukar shekaru (kamar El Niño – Southern Oscillation) zuwa shekaru gommai ko ƙarni.[46] Sauran canje-canje ana haifar dasu ne ta hanyar rashin daidaiton kuzari wanda yake "waje" ga tsarin yanayi, Amma ba koyaushe yake waje da Duniya ba.[47] Misalan abubuwan karfafa na waje sun haɗa da canje-canje a cikin yanayin sararin samaniya (misali ƙarar haɓakar iskar gas), hasken rana, fitowar dutsen dutse, da kuma bambancin da kewayar duniya da ke kewaye da Rana.[48]

Yanayin canjin yanayi shine kokarin nuna ilimin kimiyya wadanne hanyoyin suke da alhakin canje-canjen da aka lura a cikin yanayin duniya. Don ƙayyade halayen anthropogenic, sanannen canjin yanayin cikin gida da tilas da ƙirar waje na halitta ana buƙatar fitar da su. Saboda haka, babbar hanya ita ce yin amfani da samfurin kwamfuta ta tsarin sauyin yanayi don tantance "zanan yatsun hannu" na musamman don duk dalilan da ke iya haifar da shi. Ta hanyar kwatanta waɗannan zanan yatsun hannu tare da alamun da aka lura da kuma canjin canjin yanayi, da kuma tarihin da aka kiyaye na tilastawa, ana iya ƙayyade dalilan sauyin da aka lura.[49] Misali, tilasta yin amfani da hasken rana ba zai zama babban dalili ba saboda yatsan yatsa yana dumamawa a cikin yanayi duka, kuma ƙananan yanayi ne kawai ya warmed, wanda shine abin da ake tsammani daga iskar gas mai zafi (wanda ke kama tarkon zafin da yake fitowa daga sama).[50] Bayanin canjin yanayi na kwanan nan ya nuna cewa babban abin da ke haifar da hakan shine gas mai dumama yanayi, kuma na biyun sauyin amfani da ƙasa, da aerosol da ƙoshin lafiya.[51]

Iskar gas.

gyara sashe
 
CO2 kididdiga a cikin shekaru 800,000 na ƙarshe kamar yadda aka auna daga dusar kankara (shuɗi / kore) kuma kai tsaye (baƙi)

Duniya na daukar hasken rana, sannan ta haskaka shi azaman zafi. Wasu daga cikin wannan hasken infrared yana sharar iskar gas mai guba a cikin sararin samaniya, kuma saboda sake fitar da shi ta kowane bangare wani ɓangare na zafin yana kamawa a cikin Duniya maimakon tserewa zuwa sararin samaniya.[52] Kafin Juyin Juya Halin Masana'antu, yawan iskar gas mai gurɓataccen yanayi ya sa iska kusa da farfajiya ta kasance kusan 33°C (59°F) dumi fiye da yadda zai kasance a rashi.[53] Ba tare da yanayin duniya ba, da matsakaita zafin duniya zai yi kasa da daskarewa na ruwa.[54] Duk da yake tururin ruwa (~50%) da gajimare (~25%) sune manyan masu ba da gudummawa ga tasirin koren yanayi, Suna ƙaruwa azaman aiki na yanayin zafin jiki kuma saboda haka ana ɗaukar su ra'ayoyi. A gefe guda, yawan gas kamar CO2 (~20%), ozone da nitrous oxide basu da dogaro da yanayin zafin jiki, kuma saboda haka ake ɗaukar su da tilastawa waje.[55] Ozone yana aiki a matsayin iskar gas a cikin mafi ƙasƙantar layin sararin samaniya, yanayin sararin samaniya (sabanin yanayin ozone na stratospheric). Bugu da ƙari, ozone yana aiki sosai kuma yana hulɗa tare da sauran iskar gas da aerosols.[56]

Ayyukan mutane tun daga Juyin Juya Halin Masana'antu, galibi cirewa da ƙone man burbushin (kwal, mai, da iskar gas),[57] ya kara yawan iskar gas a cikin yanayi. Wadannan suna ƙaruwa a matakan gas kamar CO2, methane, tropospheric ozone, CFCs, da nitrous oxide sun haɓaka tilasta radiative. A cikin 2018, ƙididdigar CO2 kuma methane ya karu da kusan kashi 45% da 160%, bi da bi, tun shekara ta 1750.[58] A cikin 2013, karatun CO2 da aka ɗauka a shafin farko na duniya a Mauna Loa ya zarce 400, ppm a karo na farko (matakan pre-masana'antu na yau da kullun sun kasance ~270ppm).[59] Wadannan CO2 Matakan sun fi yadda suka kasance a kowane lokaci a cikin shekaru 800,000, da suka gabata, lokacin da aka tattara ingantattun bayanai don iska da aka makale a cikin dusar ƙanƙanra.[60] Ananan shaidar ilimin ƙasa kai tsaye suna nuna cewa CO

Valuesimomi 2 ba su da yawa wannan tsawon miliyoyin shekaru.[61]

 
Aikin Carbon na Duniya ya nuna yadda ƙari zuwa CO2 tun daga 1880 an haifar da su ta hanyoyi daban-daban suna haɓaka ɗaya bayan ɗaya.

Haɗaɗɗen iskar gas na anthropogenic na duniya a cikin 2018, ban da waɗanda daga canjin amfani da ƙasa, sun yi daidai da tan biliyan 52 na CO2. Daga cikin waɗannan hayakin da aka fitar, kashi 72 cikin ɗari ya kasance CO2, 19% shine methane, 6% sunadarin nitrous, kuma 3% sunadarin gas ne. Haɗin CO2 da farko ya fito ne daga ƙona burbushin mai don samar da haske mai amfani da makamashi mai zafi don jigilar kayayyaki, ƙera masana'antu, dumama wutar lantarki.[62] Emarin fitar da CO2 ya fito ne daga sare dazuzzuka da kuma masana'antun masana'antu, waɗanda suka haɗa da CO2 da aka fitar ta halayen sunadarai don yin suminti, ƙarfe, aluminum, da takin zamani.[63] Haɗin methane yana zuwa ne daga dabbobi, taki, noman shinkafa, wuraren shara, ruwa mai ƙaya, hakar kwal, da kuma hakar mai da gas.[64] Haɗakar da ke cikin iska mai ƙoshin lafiya ta fito ne daga bazuwar ƙwayoyin ƙwayoyin cuta na ƙwayoyin cuta da takin gargajiya.[65].

Manazarta.

gyara sashe
  1. IPCC AR5 WG1 Summary for Policymakers 2013, p. 4: 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; Gleick, 7 January 2017
  2. IPCC SR15 Ch1 2018, p. 54: Abundant empirical evidence of the unprecedented rate and global scale of impact of human influence on the Earth System (Steffen et al., 2016; Waters et al., 2016) has led many scientists to call for an acknowledgement that the Earth has entered a new geological epoch: the Anthropocene.
  3. "Scientific Consensus: Earth's Climate is Warming". Climate Change: Vital Signs of the Planet. NASA JPL. Archived from the original on 28 March 2020. Retrieved 29 March 2020.
  4. EPA 2020: Carbon dioxide (76%), Methane (16%), Nitrous Oxide (6%).
  5. EPA 2020: Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions (e.g., manufacture of cement). Fossil fuel use is the primary source of CO2. CO2 can also be emitted from direct human-induced impacts on forestry and other land use, such as through deforestation, land clearing for agriculture, and degradation of soils. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
  6. USGCRP Chapter 3 2017 Figure 3.1 panel 2, Figure 3.3 panel 5.
  7. IPCC SRCCL 2019, p. 7: Since the pre-industrial period, the land surface air temperature has risen nearly twice as much as the global average temperature (high confidence). Climate change... contributed to desertification and land degradation in many regions (high confidence).; IPCC SRCCL 2019, p. 45: Climate change is playing an increasing role in determining wildfire regimes alongside human activity (medium confidence), with future climate variability expected to enhance the risk and severity of wildfires in many biomes such as tropical rainforests (high confidence).
  8. IPCC SROCC 2019, p. 16: Over the last decades, global warming has led to widespread shrinking of the cryosphere, with mass loss from ice sheets and glaciers (very high confidence), reductions in snow cover (high confidence) and Arctic sea ice extent and thickness (very high confidence), and increased permafrost temperature (very high confidence).
  9. IPCC SRCCL 2019, p. 7: Climate change, including increases in frequency and intensity of extremes, has adversely impacted food security and terrestrial ecosystems as well as contributed to desertification and land degradation in many regions (high confidence).
  10. IPCC SROCC 2019, p. 22: Ocean warming in the 20th century and beyond has contributed to an overall decrease in maximum catch potential (medium confidence), compounding the impacts from overfishing for some fish stocks (high confidence). In many regions, declines in the abundance of fish and shellfish stocks due to direct and indirect effects of global warming and biogeochemical changes have already contributed to reduced fisheries catches (high confidence).
  11. WHO, Nov 2015: Climate change is the greatest threat to global health in the 21st century.
  12. EPA (19 January 2017). "Climate Impacts on Ecosystems". Archived from the original on 27 January 2018. Retrieved 5 February 2019. Mountain and arctic ecosystems and species are particularly sensitive to climate change... As ocean temperatures warm and the acidity of the ocean increases, bleaching and coral die-offs are likely to become more frequent.CS1 maint: ref=harv (link)
  13. IPCC SR15 Ch1 2018, p. 64: Sustained net zero anthropogenic emissions of CO2 and declining net anthropogenic non-CO2 radiative forcing over a multi-decade period would halt anthropogenic global warming over that period, although it would not halt sea level rise or many other aspects of climate system adjustment.
  14. "Climate Change: Global Temperature".
  15. IPCC SR15 Summary for Policymakers 2018, p. 7: Future climate-related risks ... are larger if global warming exceeds 1.5 °C (2.7 °F) before returning to that level by 2100 than if global warming gradually stabilizes at 1.5°C. ... Some impacts may be long-lasting or irreversible, such as the loss of some ecosystems (high confidence).
  16. Climate Action Tracker 2019, p. 1: Under current pledges, the world will warm by 2.8°C by the end of the century, close to twice the limit they agreed in Paris. Governments are even further from the Paris temperature limit in terms of their real-world action, which would see the temperature rise by 3°C.; United Nations Environment Programme 2019, p. 27.
  17. IPCC SR15 Ch2 2018, p. 95: In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range); Rogelj et al. 2015.
  18. Neukom et al. 2019.
  19. "Global Annual Mean Surface Air Temperature Change". NASA. Retrieved 23 February 2020.
  20. "Global Annual Mean Surface Air Temperature Change". NASA. Retrieved 23 February 2020.
  21. EPA 2016: 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).
  22. IPCC SR15 Summary for Policymakers 2018, p. 4; WMO 2019, p. 6.
  23. IPCC SR15 Ch1 2018, p. 81.
  24. IPCC AR5 WG1 Ch2 2013, p. 162.
  25. IPCC AR5 WG1 Ch5 2013, p. 386; Neukom et al. 2019.
  26. IPCC AR5 WG1 Ch5 2013, pp. 389, 399–400: "The PETM [around 55.5–55.3 million years ago] was marked by ... global warming of 4 °C to 7 °C ... 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."
  27. IPCC SR15 Ch1 2018, p. 54.
  28. IPCC SR15 Ch1 2018, p. 57: This report adopts the 51-year reference period, 1850–1900 inclusive, assessed as an approximation of pre-industrial levels in AR5 ... Temperatures rose by 0.0 °C–0.2 °C from 1720–1800 to 1850–1900; Hawkins et al. 2017, p. 1844.
  29. IPCC SR15 Ch1 2018, p. 57: This report adopts the 51-year reference period, 1850–1900 inclusive, assessed as an approximation of pre-industrial levels in AR5 ... Temperatures rose by 0.0 °C–0.2 °C from 1720–1800 to 1850–1900; Hawkins et al. 2017, p. 1844.
  30. IPCC AR5 WG1 Summary for Policymakers 2013, pp. 4–5: "Global-scale observations from the instrumental era began in the mid-19th century for temperature and other variables ... the period 1880 to 2012 ... multiple independently produced datasets exist."
  31. Kennedy et al. 2010, p. S26. Figure 2.5.
  32. Kennedy et al. 2010, pp. S26, S59-S60; USGCRP Chapter 1 2017, p. 35.
  33. IPCC AR4 WG2 Ch1 2007, Sec. 1.3.5.1, p. 99.
  34. "Global Warming". NASA JPL. Retrieved 11 September 2020. Satellite measurements show warming in the troposphere but cooling in the stratosphere. This vertical pattern is consistent with global warming due to increasing greenhouse gases, but inconsistent with warming from natural causes.
  35. Sévellec & Drijfhout 2018.
  36. England et al. 2014; Knight et al. 2009.
  37. Lindsey 2018.
  38. IPCC SRCCL Summary for Policymakers 2019, p. 7.
  39. Sutton, Dong & Gregory 2007.
  40. "Climate Change: Ocean Heat Content". NOAA. 2018. Archived from the original on 12 February 2019. Retrieved 20 February 2019.
  41. IPCC AR5 WG1 Ch3 2013, p. 257: "Ocean warming dominates the global energy change inventory. Warming of the ocean accounts for about 93% of the increase in the Earth's energy inventory between 1971 and 2010 (high confidence), with warming of the upper (0 to 700 m) ocean accounting for about 64% of the total.
  42. Cazenave et al. 2014.
  43. NOAA, 10 July 2011.
  44. IPCC AR5 WG1 Ch12 2013, p. 1062; Cohen et al. 2014.
  45. NASA, 12 September 2018.
  46. Delworth & Zeng 2012, p. 5; Franzke et al. 2020.
  47. National Research Council 2012, p. 9.
  48. IPCC AR5 WG1 Ch10 2013, p. 916.
  49. Knutson 2017, p. 443; IPCC AR5 WG1 Ch10 2013, pp. 875–876.
  50. USGCRP 2009, p. 20.
  51. IPCC AR5 WG1 Summary for Policymakers 2013, pp. 13–14.
  52. NASA. "The Causes of Climate Change". Climate Change: Vital Signs of the Planet. Archived from the original on 8 May 2019. Retrieved 8 May 2019.
  53. IPCC AR4 WG1 Ch1 2007, FAQ1.1: "To emit 240 W m−2, a surface would have to have a temperature of around −19 °C (−2 °F). This is much colder than the conditions that actually exist at the Earth's surface (the global mean surface temperature is about 14 °C).
  54. ACS. "What Is the Greenhouse Effect?". Archived from the original on 26 May 2019. Retrieved 26 May 2019.
  55. Schmidt et al. 2010; USGCRP Climate Science Supplement 2014, p. 742.
  56. Wang, Shugart & Lerdau 2017.
  57. The Guardian, 19 February 2020.
  58. WMO 2020, p. 5.
  59. BBC, 10 May 2013; Schiermeier 2015.
  60. Siegenthaler et al. 2005; Lüthi et al. 2008.
  61. BBC, 10 May 2013.
  62. EPA 2020: The main human activity that emits CO2 is the combustion of fossil fuels (coal, natural gas, and oil) for energy and transportation, although certain industrial processes and land-use changes also emit CO2.
  63. Olivier & Peters 2019, p. 17; Union of Concerned Scientists, 9 December 2012: When trees are cut down and burned or allowed to rot, their stored carbon is released into the air as carbon dioxide; EPA 2020: Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy, as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials; "Redox, extraction of iron and transition metals". Hot air (oxygen) reacts with the coke (carbon) to produce carbon dioxide and heat energy to heat up the furnace. Removing impurities: The calcium carbonate in the limestone thermally decomposes to form calcium oxide. calcium carbonate → calcium oxide + carbon dioxide; "The Aluminum Smelting Process". Carbon dioxide gas is formed at the anode, as the carbon anode is consumed upon reaction of carbon with the oxygen ions from the alumina (Al2O3). Formation of carbon dioxide is unavoidable as long as carbon anodes are used, and it is of great concern because CO2 is a greenhouse gas; {{url=https://cen.acs.org/business/inorganic-chemicals/Making-aluminum-without-making-CO2/96/i21 | title=Making aluminum without making CO2 | quote=Aluminum has been made the same way since 1886, when the American chemist Charles Martin Hall and the Frenchman Paul Héroult almost simultaneously developed an electrolytic technique for reducing aluminum oxide in a bath of molten cryolite (hexafluoroaluminate). The process uses a carbon-rich anode that reacts with the generated oxygen to form CO2.}}; "Industrial ammonia production emits more CO2 than any other chemical-making reaction. Chemists want to change that". Hydrogen used for the reaction comes from natural gas, coal, or oil through processes that release CO2. According to a 2013 joint report from the International Energy Agency, the International Council of Chemical Associations, and the Society for Chemical Engineering and Biotechnology, CO2 emissions from hydrogen production account for more than half of those from the entire ammonia production process. In total, from hydrocarbon feedstocks to NH3 synthesis, every NH3 molecule generated releases one molecule of CO2 as a coproduct.
  64. EPA 2020; Global Methane Initiative 2020: Estimated Global Anthropogenic Methane Emissions by Source, 2020: Enteric fermentation (27%), Manure Management (3%), Coal Mining (9%), Municipal Solid Waste (11%), Oil & Gas (24%), Wastewater (7%), Rice Cultivation (7%).
  65. Canjin yanayi; Ɗaya daga cikin mahimman bayanai game da sauyin yanayi shine cewa yana faruwa ne ta hanyar fitar da iskar gas, kamar carbon dioxide, zuwa cikin yanayi. Wadannan iskar gas suna kama zafi daga rana kuma suna sa duniyar ta yi zafi. Wannan na iya haifar da sakamako da yawa, kamar narkewar kankara, hauhawar matakan teku, yawan guguwa da yawa, da canje-canje a wuraren zama na namun daji. Tabbas! Wani muhimmin al'amari game da sauyin yanayi shi ne cewa matsala ce ta duniya da ke buƙatar mafita a duniya. Ko da wata kasa ta rage yawan hayakin da take fitarwa, ba za ta isa ta hana sauyin yanayi ba. Wannan shine dalilin da ya sa yarjejeniyar kasa da kasa, kamar yarjejeniyar Paris, ke da mahimmanci. Michigan State University 2014: Nitrous oxide is produced by microbes in almost all soils. In agriculture, N2O is emitted mainly from fertilized soils and animal wastes—wherever nitrogen (N) is readily available.; EPA 2019: Agricultural activities, such as fertilizer use, are the primary source of N2O emissions; Davidson 2009: 2.0% of manure nitrogen and 2.5% of fertilizer nitrogen was converted to nitrous oxide between 1860 and 2005; these percentage contributions explain the entire pattern of increasing nitrous oxide concentrations over this period.