The environmental non - profit CDP has published its first - ever ranking of cities ’ responses to climate change . A top level “ A ” rating has been awarded to 43 of the 596 cities ranked , including Barcelona , Cape Town , Hong Kong , London and Paris . CDP also cited 14 cities , including Boston , the Hague and Sydney , which aim to be climate or carbon neutral by 2020 . Melbourne aims to be carbon neutral by 2020, Reykjavík by 2040 and The Hague by 2030. Several cities , including London , Paris and San Francisco , have 100 % renewable energy targets , while Reykjavík has already achieved this goal . Cities house over 50 % of the global population and are responsible for over 70 % of energy - related carbon emissions .
The environmental non - profit CDP has published its first - ever ranking of cities ’ responses to climate change . A top level “ A ” rating has been awarded to 43 of the 596 cities ranked , including Barcelona , Cape Town , Hong Kong , London and Paris . CDP also cited 14 cities , including Boston , the Hague and Sydney , which aim to be climate or carbon neutral by 2020 . Several cities , including London , Paris and San Francisco , have 100 % renewable energy targets , while Reykjavík has already achieved this goal . Cities house over 50 % of the global population and are responsible for over 70 % of energy - related carbon emissions .