Effect+of+man+on+nature

 Encyclopædia Britannica ||
 * =North America =


 * [[image:http://library.eb.com.au/bcom/images/dot.gif height="10"]] ||


Before the arrival of Europeans in North America, the impact of human activity on the environment seems to have been minimal, aside from the burning of the prairies by Native Americans (First Nations, American Indians). The attitude of the European immigrants and their descendants favoured clearing the forests and killing off the wildlife, with the aim of making room for agriculture and urban centres. In a continent that was so vast and at the same time so empty, they also developed the idea that environmental resources were unlimited and only awaited people to exploit them. It should be remembered that many of these immigrants came from a Europe in which, during the agricultural and Industrial revolutions, there had been an increasing attack on natural resources, particularly associated with the rise of heavily industrialized cities. When the United States and Canada became industrialized, they used coal, oil, iron, other metals, and wood with extravagance and often with great waste. The waste products of the factories of these countries started to pollute air, land, and water, and, as cities with enormous populations began to appear, most people came to live in an environment sharply modified by human activity. By the mid-20th century the people of the United States had killed off about four-fifths of the country's wildlife, cut more than half of its timber, plowed up nearly all of its grassland, and used up two-fifths of its high-grade iron ore; the country was consuming its oil so fast that, even with its great resources, it began to import enormous quantities from other countries. Soil erosion also became rampant, as agriculture was practiced carelessly or on land with marginal producing capacity. Conscious of the great drain on the resources of the country and suffering from the increasing ill effects of pollution, the United States began attempts to conserve its reserves of soil, water, fuels, and minerals and to replant forests or otherwise manage them for efficient regrowth. The country has since come to lead the world in conservation programs, particularly in renewing forests and grasslands, conserving soils, and effectively controlling the waters. Canada, too, has an active conservation program and was the first North American country to pass clean-water legislation to help fight the pollution of its lakes and streams. Mexico likewise has initiated an active, though limited, conservation effort. Other environmentally positive actions—such as energy conservation and recycling materials otherwise discarded as solid waste—have helped in the northern part of the continent to offset the effects of increased population pressure on the land.

== == > Encyclopædia Britannica, Inc., 2011. Web. 12 Sept. 2011.
 * " **North America .**" //Encyclopædia Britannica//. //Encyclopædia Britannica Online Library Edition//.