Environmental Change in Mountains and Uplands



The influence of humankind on the natural resources of Earth over the past 300 years has been simply astonishing. Thirty to 50 percent of the land surface has been transformed by human action; more than half of all accessible fresh waters are used for human activities; SO2 and fixed nitrogen production from human activities are greater than from all natural sources combined; and emissions of important greenhouse gases have increased to the point at which global climate is affected. No place on Earth has been untouched, though some regions have been more permanently altered than others.