In our local region one problem is that the 'city' is heavily concreted. There's a distinct lack of green in many areas. In the summer and in particular this year, but other heatwaves as well, this becomes punishing in the city: concrete absorbs the heat during the day and radiates it at night, making the city even hotter.
See the sibling comment about whether the CO2 numbers make sense, but I also think with warming environs locally we're going to have to get a lot smarter about how we build to manage heat as well. There was a fascinating article on HN a while ago about the London Underground and the troubles they're having cooling it... The Swiss build a lot with concrete in their cities and there's going to be a corresponding difficulty of keeping them cool.