Group items tagged

Dogs have been used as guards, hunters, draught animals, eyes for the blind, drug and explosive detectors, rodent controllers- and even weapons! In Roman times and the Middle Ages, mastiffs wearing light armour, carrying spikes and pots of flaming sulphur and resin ran into battle against mounted knights. In World War II the Russians trained dogs to run suicide missions between the tracks of German tanks with mines strapped on their backs.

For example, some types of water pollution change the color of the water in a lake or stream, whereas other types are less visible, but both can be equally detrimental to the health of humans and nonhuman animals.

For example, 2,000 years ago, when the Romans smelted silver, lead was released into the environment and carried by the wind over long distances; this lead can still be detected in Scandinavian lake sediments.

Relatively few of these new compounds have been thoroughly tested for possible health or environmental effects.

In 2002 about 40% of U.S. carbon dioxide emissions stem from the burning of fossil fuels for the purpose of electricity generation. Coal accounts for 93 percent of the emissions from the electric utility industry. US Emissions Inventory 2004 Executive Summary p. 10 Coal emits around 1.7 times as much carbon per unit of energy when burned as does natural gas and 1.25 times as much as oil. Natural gas gives off 50% of the carbon dioxide, the principal greenhouse gas, released by coal and 25% less carbon dioxide than oil, for the same amount of energy produced. Coal contains about 80 percent more carbon per unit of energy than gas does, and oil contains about 40 percent more. For the typical U.S. household, a metric ton of carbon equals about 10,000 miles of driving at 25 miles per gallon of gasoline or about one year of home heating using a natural gas-fired furnace or about four months of electricity from coal-fired generation.