How has our dependence on fossil fuels changed our world?
In a sense, the environmental health of the world was condemned with Industrialisation, that resulted in the increasing dependence of the world's civilisations on fossil fuels to spur economic development. This is because, both in the way that such fuels are gained and also in the resulting effects of burning fossil fuels such as oil, the earth is damaged as a result.
The way in which fossil fuels are extracted from the earth is a cause of some notoriety, and we are now so saturated with press stories of oil spills and gas leaks that have massive environmental repercussions that we seem numb to the true import of such stories. There are massive concerns about the tapping of oil in such unsullied environmental zones as Alaska and Antarctica, and great worries about the impact of man's ever more desperate search for fossil fuels in these parts of the world.
Secondly, it is now a well-known fact that the burning of fossil fuels creates more carbon dioxide in the atmosphere, which in turn reflects the sun's rays creating a kind of greenhouse effect in the earth's atmosphere. As the ozone layer acts as a panel of glass which helps intensifty the impact of the sun, and the increased amount of CO2 in the atmosphere magnifies this effect, the greenhouse effect is something that will continue to increase resulting in the melting of glaciers, putting the world's water supply into jeaopardy and also threatening many low-lying areas of the world such as Bangladesh, which will flood.
I have included two links below to give you more information on these two aspects.