There WILL be some countries that will benefit from global warming in the long run, most notably Russia and Canada. More land will be habitable, more land will be arable, and the Northeast and Northwest passages will become navigable more of the year. However even in the short run they are suffering; both countries had horrible forest fires this past summer because of heat and drought.
For most of the rest of the world, there isn’t much benefit. And if the sea level does rise, we will be facing Katrinas all over the world.