Global warming does not, paradoxically, mean that the whole globe just gets hotter! It does however mean that the overall average temperature will increase. It also means there will be more extreme weather in various parts of the world. For instance if the seas get a little warmer, it may stop or diminish the Gulf Stream, which would mean that northern Europe will experience much colder winters.
It's very complex, and we may just be going through the normal cycles that global temperature has experienced countless times for a couple of billion years. We are probably not helping though.