Yarjejeniyar kimiyya game da canjin yanayi

Akwai kusan Yarjejeniyar kimiyya guda ɗaya cewa Duniya tana ci gaba da dumama tun farkon Juyin Juya Halin Masana'antu, cewa yawan dumama na baya-bayan nan ba a taɓa gani ba, : 8 : 11 kuma wannan dumama galibi sakamakon saurin karuwa ne na carbon dioxide na yanayi (CO2) wanda ayyukan ɗan adam suka haifar. Ayyukan ɗan adam da ke haifar da wannan dumama sun haɗa da konewar man fetur, samar da siminti, da canje-canje na Amfani da ƙasa kamar lalata gandun daji, : 10-11 tare da muhimmiyar rawar goyon baya daga sauran iskar gas kamar methane da nitrous oxide. : 7 Wannan rawar ɗan adam a cikin canjin yanayi ana ɗaukarsa "ba tare da wata shakka ba" kuma "ba za a iya musantawa ba". : 4 

Kusan dukkanin masana kimiyya masu wallafa yanayi suna cewa mutane suna haifar da canjin yanayi. Binciken wallafe-wallafen kimiyya wata hanya ce ta auna yarjejeniyar kimiyya. Binciken 2019 na takardun kimiyya ya sami yarjejeniya game da dalilin canjin yanayi ya kasance a 100%,  kuma binciken 2021 ya kammala cewa sama da 99% na takardon kimiyya sun yarda da dalilin ɗan adam na canjin yanayi.  Ƙananan kashi na takardun da ba su yarda da yarjejeniyar ba sau da yawa suna ƙunshe da kurakurai ko kuma ba za a iya maimaita su ba.

Shaidar da ke nuna dumamar yanayi saboda tasirin ɗan adam an gane shi daga makarantun kimiyya na ƙasa na duk manyan ƙasashe masu ci gaban masana'antu. A cikin wallafe-wallafen kimiyya, akwai yarjejeniya mai ƙarfi cewa yanayin zafi na duniya ya karu a cikin 'yan shekarun da suka gabata kuma cewa yanayin yana faruwa ne sakamakon fitar da iskar gas da mutane ke haifarwa. Babu wata ƙungiyar kimiyya ta ƙasa ko ta ƙasa da ƙasa da ta yarda da wannan ra'ayi. Wasu 'yan kungiyoyi da ke da mambobi a masana'antun sarrafa kayan aiki suna rike da mukamai marasa aiki, wasu kuma sun yi ƙoƙari su jawo hankalin jama'a cewa sauyin yanayi ba ya faruwa, ko kuma idan yanayin yana canzawa ba saboda tasirin ɗan adam ba ne, suna ƙoƙarin shuka shakku a cikin ijma'in kimiyya..

## Kasancewar yarjejeniyar kimiyya

An gudanar da nazarin ra'ayin kimiyya game da canjin yanayi tun daga shekarun 1970,  kuma suna kafa yarjejeniya mai yawa tun daga shekarun 1990,   tare da matakin yarjejeniya yana ƙaruwa a tsawon lokaci. Masana kimiyya, jami'o'i, da dakunan gwaje-gwaje suna ba da gudummawa ga ra'ayin kimiyya game da canjin yanayi ta hanyar wallafe-wallafen da An sake dubawa, yayin da hukumomin kimiyya na ƙasa ko na duniya ke taƙaita wuraren yarjejeniyar hadin gwiwa da tabbaci a cikin rahotanni na kira.

Misalan irin waɗannan rahotanni sun haɗa da ko 2004 Arctic Climate Impact Assessment daga Kwamitin Kimiyya na Arctic na Duniya da gwamnatocin Majalisar Arctic,   ko kuma Amurka' National Climate Assessment, wanda aka saki lokaci-lokaci tun daga shekara ta 2000 a ƙarƙashin jagorancin Shirin Binciken Canjin Duniya na Amurka. NCA na huɗu, wanda aka saki a cikin 2017, ya haɗa da ƙoƙarin hukumomin tarayya goma sha uku, waɗanda Hukumar Kula da Yanayi da Yanayi ta Kasa (NOAA) ta jagoranta,  da kuma kusan "mutane 1,000, gami da manyan masana kimiyya 300, kusan rabin daga waje da gwamnati. "

Majalisar Dinkin Duniya ce ta kafa kwamitin Intergovernmental kan Canjin Yanayi (IPCC) a cikin 1988,  kuma tana gabatar da rahotanni da ke taƙaita ƙarfin da girman yarjejeniya game da canjin yanayi da kuma bangarorin da yawa ga jihohin membobin Majalisar Dinkinobho, tare da manyan rahotanni waɗanda aka fitar a tsakanin shekaru 5 zuwa 7 tun daga 1990. A shekara ta 2001, makarantun kimiyya daga kasashe 17 (Australia, Belgium, Brazil, Canada, China, Faransa, Jamus, Indiya, Indonesia, Ireland, Italiya, Malaysia, New Zealand, Sweden, Trinidad, Turkiyya da Ingila) sun yi sanarwa ta hadin gwiwa da ke amincewa da aikin IPCC. Sun yarda cewa yanayin zafi yana tashi kuma zai ci gaba da tashi saboda ayyukan ɗan adam, kuma sun jaddada muhimmancin rage hayakin gas, suna kammala cewa "Kasuwanci kamar yadda ya saba ba zaɓi ne mai yiwuwa ba". Har ila yau sananne ne don kasancewa ɗaya daga cikin maganganun farko don yin amfani da kalmar "ƙaddamarwa" a bayyane. A shekara ta 2005, wata sanarwa ta hadin gwiwa daga makarantun kimiyya na manyan kasashe (Brazil, Kanada, China, Faransa, Jamus, Indiya, Italiya, Japan, Rasha, Ingila da Amurka sun kira ga ƙaddamarwar IPCC a matsayin "yancin kimiyya na duniya", kuma sun bukaci a dauki mataki na gaggawa kan sauyin yanayi da sauyin yanayi. A wasu wurare a duniya, wasu kungiyoyin da suka yi magana game da yarjejeniyar kimiyya sun hada da Cibiyar Nazarin Kimiyya ta Afirka a cikin 2007,  da kuma Ƙungiyar Duniya don Binciken Quaternary a cikin 2008. 

A cikin shekara ta 2013, wani binciken da ya gano cewa daga cikin takardun da aka sake dubawa sama da 4,000 kan kimiyyar yanayi da aka buga tun daga shekara ta 1990, kashi 97% sun yarda, a bayyane ko a bayyane, cewa dumamar duniya tana faruwa kuma ta haifar da mutum. Bincike na ra'ayoyin masana kimiyya game da canjin yanayi - tare da mai da hankali kan canjin yanayi da ya haifar da mutum - an gudanar da su tun daga shekarun 1970s. Wani bita na 2016 ya tabbatar da cewa "bincike na 97% yarjejeniya [cewa mutane suna haifar da dumamar yanayi na duniya na baya-bayan nan] a cikin binciken yanayi da aka buga yana da ƙarfi kuma ya dace da sauran binciken masana kimiyya na yanayi da nazarin da aka sake dubawa. "  Binciken 2019 ya sami yarjejeniyar kimiyya ta kasance a 100%,  kuma binciken 2021 ya gano cewa yarjejeniya ta wuce 99% .