Dimming duniya
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Ma'auni na tsari na farko na rashin haske kai tsaye a duniya ya fara ne a cikin 1950s. Ba da daɗewa ba an ga raguwar rashin haske, kuma an ba shi sunan dusashewar duniya . Ya ci gaba daga 1950s har zuwa 1980s, tare da raguwar 4-5% a kowace shekara goma, [1] ko da yake aikin hasken rana bai bambanta fiye da yadda aka saba ba a lokacin. [2] A maimakon haka an danganta raguwar dusar ƙanƙara a duniya da haɓakar abubuwan da ke cikin yanayi, galibin iskar sulfate aerosols, sakamakon gurɓatar da iska mai saurin girma sakamakon haɓakar masana'antu bayan yaƙi. Bayan 1980s, dusar ƙanƙara ta duniya ta fara juyawa, tare da raguwar gurɓataccen hayaki, a cikin abin da aka kwatanta da haskakawa na duniya, kodayake wannan juyewar ana ɗaukarsa "bangare" kawai a yanzu. [1] Juyayin kuma ya kasance ba daidai ba a duniya, yayin da yanayin raguwa ya ci gaba a cikin shekarun 1990 akan wasu galibin kasashe masu tasowa kamar Indiya, Zimbabwe, Chile da Venezuela. [3] A kan kasar Sin, yanayin dimming ya ci gaba a hankali bayan 1990, kuma bai fara komawa baya ba sai a kusa da 2005.
Dimming na duniya ya tsoma baki tare da zagayowar ruwa ta hanyar rage danshi, wanda mai yiwuwa ya rage yawan ruwan sama a wasu yankuna, [1] kuma mai yiwuwa ya haifar da canjin yanayin kudu na dukkan bel na ruwan zafi tsakanin 1950 da 1985, tare da takaitaccen murmurewa daga baya. . [4] Tunda ana buƙatar yawan ƙawancen ruwa a wurare masu zafi don fitar da lokacin damina, sanyin da ke haifar da gurɓataccen gurɓataccen abu ya bayyana yana raunana damina ta Kudancin Asiya, yayin da raguwar gurɓataccen gurɓataccen abu ke ƙarfafa shi. [5] Yawancin karatu sun kuma haɗa matakan rikodin gurɓataccen gurɓataccen gurɓataccen abu a cikin Arewacin Hemisphere zuwa rashin nasarar damina a bayan yunwar Habasha ta 1984, [6] [7] kodayake cikakken tasirin ɗan adam vs. tasirin yanayi akan wannan taron har yanzu ana jayayya. [8] A gefe guda kuma, dusar ƙanƙara ta duniya ta kuma magance wasu gurɓacewar iskar gas, yadda ya kamata, ta "rufe" adadin ɗumamar yanayi da aka fuskanta har zuwa yau, tare da mafi ƙazantar ƙazantar da ƙasa har ma da samun sanyi a cikin 1970s. Sabanin haka, haskaka duniya ya taimaka wajen haɓaka ɗumamar yanayi wanda ya fara a cikin 1990s. [1] [9]
Nan gaba kadan, ana sa ran za a ci gaba da haskakawa a duniya, yayin da kasashe ke kokarin rage yawan gurbacewar iska ga lafiyar 'yan kasarsu. Wannan kuma yana nufin rage dumamar yanayi za a rufe shi nan gaba. Samfuran yanayin yanayi suna da ikon yin kwatankwacin tasirin aerosols kamar sulfates, kuma a cikin rahoton kimantawa na IPCC na shida, an yi imanin cewa za su kashe kusan 0.5 °C (0.90 °F) . na dumama. Hakanan, yanayin yanayin canjin yanayi ya haɗa da raguwa a cikin ɓarna da sanyaya da suka bayar a cikin hasashensu, kuma wannan ya haɗa da yanayin yanayin yanayin da ake buƙata don saduwa da 1.5 °C (2.7 °F) da 2 °C (3.6 °F) hari. [10] An yi imani da cewa sanyaya da aka samar ta hanyar dimming duniya yayi kama da ɗumamar da aka samu daga methane na yanayi, ma'ana cewa raguwa a lokaci guda a duka biyu zai soke juna yadda ya kamata. Koyaya, rashin tabbas ya kasance game da wakilcin samfuran na tasirin iska akan tsarin yanayi, musamman a yankuna da ke da mafi ƙarancin tarihin tarihi na abubuwan gani na yanayi. [11]
Hanyoyin da ke bayan dusashewar duniya sun yi kama da waɗanda ke haifar da raguwar hasken rana kai tsaye bayan fashewar aman wuta . Haƙiƙa, fashewar Dutsen Pinatubo a cikin 1991 ta ɗan canza yanayin da ke haskakawa na ɗan lokaci. [12] Dukkan hanyoyin biyu ana daukar su a matsayin analog don allurar aerosol na stratospheric, sa baki na geoengineering na hasken rana wanda ke da nufin magance dumamar yanayi ta hanyar fitowar da gangan aerosols, duk da haka a mafi girman tsayi, inda za a buƙaci ƙananan ƙima kuma za a rage tasirin gurɓatawa. [13] Duk da haka, yayin da wannan sa hannun zai iya yin tasiri sosai wajen dakatarwa ko juyar da ɗumamar da babban sakamakonsa, zai kuma sami tasiri mai yawa akan zagayowar ruwa ta duniya, da yanayin yanki da yanayin muhalli . Saboda tasirinsa na ɗan lokaci ne kawai, dole ne a kiyaye shi tsawon ƙarni har sai an daidaita yawan iskar gas ɗin don gujewa saurin dawowa da tashin hankali na ɗumamar, wani lokaci ana kiranta girgiza ƙarewa . [14]