in the future many cities will be much bigger than now. what problem will this cause

There is no doubt that the world has undergone enormous changes and skyscrapers will be built increasingly. So many cities across the globe are swelling, compounding social and environmental challenges. When trees are cut down, the amount of carbon dioxide increases and the air gets warmer. This is leading to global warming. Human beings will suffer from financial loss and deaths. In addition, the growth of many cities will reduce green spaces, negatively affecting liveability. The more the population in cities, the more complex and require the effort to control the people.