It is not only CO2, there are many other chemicals that go up in the atmosphere. Some of them get into clouds and make acid rain that ruins harvests, others are toxic for the lungs of humans and animals and others change the way that sunbeams get to the sufrace of the Earth. The effects of global warming are not as much caused by the increasing temperatures themselves as much as they are caused by the change of direction of the global hot and cold air currents. :) https://www.washingtonpost.com/news/worldviews/wp/2018/05/02/as-china-cleans-up-its-act-indias-cities-named-the-worlds-most-polluted/?noredirect=on&utm_term=.52da510a5eaa