The Knowledge Frontier

Duniya da yanayiKafin bugawaNazarin bayanaiKaratun minti 4

NAWA NE DAGA CIKIN SAUYIN YANAYI NA KWANAN NAN SAUYIN DABI'AR KANTA?

Kowane yanayin canjin yanayi da muke gani haɗin abubuwa biyu ne. Na farko shi ne amsar da aka tilasta (forced response): canjin da iskar gas masu ɗumama duniya, ƙurar iska (aerosols), amfani da ƙasa da fashewar duwatsun wuta ke turawa. Na biyu shi ne sauyin cikin gida (internal variability): sauye-sauyen yanayin kansa, kamar El Niño ko jinkirin kaɗawar tekunan Pacific da Atlantic. Raba su yana da muhimmanci, duka don fahimtar sauyin yanayi da kuma don yin hukunci ko samfuran yanayi suna daidai.

Matsalar ita ce gaskiya tana gudana sau ɗaya kawai. Ana iya gudanar da samfuran yanayi sau da dama da tilastawa iri ɗaya, kuma matsakaicin waɗannan gudanarwar yana bayyana ɓangaren da aka tilasta. Amma samfuran suna da son kai (biases), kuma dabarun ƙididdiga masu sauƙi galibi suna ɗauka cewa tsarin da aka tilasta ba ya canzawa. Wani kwatance na ƙasa da ƙasa na kwanan nan na irin waɗannan hanyoyi ya gano cewa kurakurai sun kasance manya — kuma hanyoyin koyon na’ura (machine learning) ba su fi ƙididdigar gargajiya ba.

Takardar ta ba da misali na faɗakarwa: raguwar saurin ɗumamar duniya tsakanin 1998 da 2012 an fara fassara ta a matsayin alamar cewa ɗumamar da ɗan Adam ke haifarwa tana raguwa kuma samfuran ba daidai ba ne, kafin a gane ta a matsayin sauyin cikin gida.

Hanyar sadarwa da ke koyon hayaniya

Parvathi Kooloth, Wenyu Zhou da abokan aikinsu, a Pacific Northwest National Laboratory da jami’o’in California San Diego da Washington, sun gina ConvLSTM, wata hanyar sadarwar jijiyoyi da ke haɗa fahimtar tsarin wurare da ƙwaƙwalwar yadda suke canzawa. Sun horar da ita a kan manyan rukunonin kwaikwayo daga samfuran yanayi 15, ta amfani da taswirorin zafin saman ƙasa, ruwan sama da matsin iska a matakin teku. Aikinta shi ne ta gane sauye-sauyen dabi’a; abin da ya rage shi ne ɓangaren da aka tilasta.

Da aka gwada ta a kan samfuran da ba ta taɓa gani ba, ta fi hanyoyi shida da ake da su wajen zafi, ruwan sama da matsin iska a yawancin lokacin tarihi — sai dai ban da ɗaya, wani kwaikwayo da marubutan ke cewa baƙon abu ne da ba gaskiya ba. Don duniyar gaske, an yi amfani da nau’o’i goma na hanyar sadarwar, kowanne an horar da shi a kan wani rukuni daban na samfura goma, a kan yanayin da aka gani tun 1940.

Abin da ta gano a cikin bayanan gaske

  • Raguwar saurin ɗumama ta 1998–2012 ta fito a matsayin sauyin dabi’a, kamar yadda binciken baya suka kammala. Ɓangaren dabi’a na zafin duniya yana bin jinkirin kaɗawar Pacific sosai.
  • Arctic. Ɗumamar Arctic da aka gani ta kai kwanan nan kusan sau huɗu na saurin duniya. A cewar hanyar sadarwar, ɓangaren da aka tilasta ya kasance kusan a tsaye a kusan sau uku. Sauye-sauyen dabi’a ne suka yi sauran: Pacific ta hana ɗumamar duniya yayin da wata kaɗawa ta yankin kanta, wani salon sauyi na Arctic, ya ƙara ɗumama a can, musamman a 2005–2020.
  • Atlantic. Bambancin zafi tsakanin Arewa da Kudancin Atlantic ya bi siffar V tun 1950. Ɓangaren da aka tilasta shi ma yana sauka ya hau, daidai da hauhawa da kuma raguwar gurɓatar ƙurar iska a Arewacin Duniya daga baya. Sauyin dabi’a ya ƙara girman wannan juyawa, ya haifar da zurfin gangarowa na shekarun 1970 da 1980.
  • Pacific da kudu maso yammacin Amurka. Tun 1980, gabashin Pacific na ekweta ya ɗumama ƙasa da yamma, wani tsari “mai kama da La Niña” wanda samfura ba safai suke maimaita shi ba. Hanyar sadarwar ta ce amsar da aka tilasta ita kaɗai da ta haifar da wani rauni kishiyar tsari, “mai kama da El Niño”; sauyin dabi’a ya juya shi. Haka abin yake ga ƙarfafuwar matsin iska mai yawa a saman arewa maso gabashin Pacific da bushewar kudu maso yammacin Arewacin Amurka: galibi na dabi’a, da ɗan ƙaramin rabo da aka tilasta.

Ga da yawa daga cikin waɗannan siffofi, yanayin canjin da aka gani a 1980–2022 yana waje da iyakar amsar da aka tilasta da aka ƙiyasta — tunatarwa cewa yanayin canji guda ɗaya na tarihi zai iya zama mummunan jagora ga abin da ɗan Adam ya haifar.

Bincika samfuran

Saboda hanyar sadarwar tana ba da ƙiyasi bayyananne na ɓangaren da aka tilasta, ana iya kwatanta shi kai tsaye da abin da samfura ke kwaikwaya. Manyan tsare-tsare sun yarda: ƙarin ɗumama a kan ƙasa da a manyan latitudes, ƙasa a kan arewacin Atlantic na kusa da sanyi da Tekun Kudu, wuraren tropics da manyan latitudes masu ƙarin danshi, wuraren subtropics masu bushewa. Amma samfuran suna ɗumama Arewacin Duniya fiye da haka, suna ƙarfafa matsin iska mai yawa na subtropics ƙasa da haka, kuma suna bushe ƙasa ƙasa da haka. Marubutan suna nuna cewa samfuran yanzu na iya rage ƙiyasin yadda canjin iska zai bushe nahiyoyi.

Su da kansu sun lissafa iyakokin. Hanyar sadarwar tana koyo ne daga samfura, don haka son kai da duk samfuran suka yi tarayya a ciki zai iya ɓatar da ita. Dalilin da ya sa take aiki da kyau haka yana da wuyar gani a cikinta. Kuma tana ɗauka cewa matsakaicin rukunin kwaikwayo masu iyaka shi ne ainihin amsar da aka tilasta. A cikin waɗannan iyakoki, marubutan sun kammala, koyon na’ura zai iya ƙarfafa danganta sauyin yanayi na baya ga musabbabinsa — kuma ya ƙara kaifin gwajin samfura.