"double carbon", i.e. peak carbon 碳達峰|碳达峰[tan4 da2 feng1] and carbon neutrality 碳中和[tan4 zhong1 he2]; China's double carbon policy, announced in 2020, which aims to reach peak carbon use by 2030 and achieve carbon neutrality by 2060
trad. 雙碳
Also written 雙碳【shuāng tàn】