Destruction of the ozone layer is largely due to accumulation of chlorofluorocarbons used as aerosol propellants and in refrigeration. The chlorine is released in other reactions and reacts with additional ozone molecules. Ozone depletion could have serious consequences. Increases are expected in lethal and nonlethal forms of skin cancer and cataracts among humans. The exploding human population is altering habitats and reducing biodiversity worldwide The growth of human populations, human activities, and our technological capabilities have disrupted the trophic structure, energy flow, and chemical cycling of ecosystems in most areas of the world.
Some effects are local while others affect the biosphere's distribution and diversity of organisms.
The destruction of natural systems due to human encroachment has resulted in only a small proportion of natural, undisturbed habitat remaining in existence. Tropical rainforests are being cut at a rate of 500,000 km 2 per year and will be eliminated in a couple of decades. Human activities that disrupt entire systems include development, logging, war, and oil spills. One result of the destruction of natural habitat will be the loss of biodiversity.