Canjin yanayi ya haɗa da dumamar yanayi wanda hayakin dan Adam na iskar gas, da kuma sauye-sauye masu yawa na yanayi. Koda yake canjin yanayi ya gabata a baya, tun daga tsakiyar karni na ashirin 20, yawan girman tasirin dan Adam kan tsarin yanayi na duniya da kuma girman tasirin wannan tassin ba a taba yin irin sa ba. Wannan aikin ɗan adam ya haifar da canjin yanayi ba wata ƙungiyar kimiyya ta ƙasa ko ta ƙasa ke jayayya ba. Babban direba shine fitarwa na iskar gas, wanda sama da 90% shine carbon dioxide (CO2) da methane. Kone burbushin mai don amfani da makamashi shine asalin tushen fitar da wannan hayaƙin, tare da ƙarin gudummawa daga harkar noma, sare bishiyoyi, da kuma matakan masana'antu. 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. Saboda yanayin samaniya yayi zafi fiye da na teku, hamada tana faɗaɗa kuma zafi da wutar daji sun fi zama ruwan dare.