One effect:

As long as the global temperature is increasing, the water in the seas and oceans will expend in volume, which can cause a serious problems for the cities that will face a huge rise in the sea level especially those cities which are near to the coast. Not only that, but also some cities may be disappeared on the next 50years. When the sea level will rise the marine life will be harmfully affected. Also some of the sea Marin will extinct, so maybe one day will come and we will not find some kinds of fish.