Over production of CFC gases. CO2 too, we humans are breaking the CO2 cycle, trees "catch" the CO2 as well as icebergs, as even the soil. When we extract gas from Earth we are taking away the gases kept there for generations and generations. And the amount we are taking off to the atmosphere is not below the amount the Earth can "catch" back, so that we have more and more CO2 in the atmosphere, leading a lot of problems.
I dont know if I answered it completely but it's something.
