carbon-zero      
adjective  environment, business specialized uk/ˌkɑː.bənˈzɪə.rəʊ/ us/ˌkɑːr.bənˈzɪr.oʊ/
 零碳(一家企业或机构不向环境中释放任何二氧化碳,或释放与吸收二氧化碳的量相同)
If a company or an organization is carbon-zero, it does not release any carbon dioxide into the environment or it removes the same amount of carbon dioxide from the environment as it puts into it.
 See also: carbon neutral