Officials in Denmark are trying to hammer out the details of a new deal on global emissions. It could mean we have to limit how much energy we use.
Newsbeat's travelling around the UK to find out how cutting carbon emissions could affect our everyday lives.
For our second feature we're looking into how we travel. Ministers want more of us to start using electric cars - but can they convince petrolheads like Radio 1 and 1Xtra DJ Tim Westwood?