There are many consequences of human activities on the environment. Most of the ones that we notice are negative.
Some consequences of human activities are very easily seen. When there are too many cars and too many factories in a city, we can easily see the pollution in the air. When waste from factories and such is pumped into rivers, we can see that the water is dirty and that it stinks and has very little life in it.
Other kinds of consequences are less easily noticed. The most important of these is global warming. This is something that cannot be perceived by the average person, but it is also the consequence that might potentially have the greatest impact on life on the planet.
one of the main reasons of human activites is the ecological imbalance of environment..starting with clearing of forest for industry or residential areas.....recent example i would cite is real estate business which boasts residence near natures beauty. but the people doesn't think we are in a way destroying our environment.
forget about industries, we are sacrificing our environment for the sake few years happiness