carbon

When humans hunt and fish, they tend to favor animals that provide significant resources. In the oceans, whales, sharks and other large vertebrates have been targeted for centuries, and while the international ban on whaling has helped some species recover in select areas, many populations have fallen to a fraction of their natural levels.

On summer days, city air can be 5 or more degrees warmer than that in surrounding areas. Known as the “urban heat island effect,” it results in part from limited shade trees and the large surface area of pavement and dark roofing materials.

Over the past five years the price of oil has gone through wild swings — record highs are followed by more “normal” periods, sharp spikes alternate with modest troughs. Powering all this volatility is a complex mix of economics, political factors and industry developments.

Numerous studies have shown that automotive pollution has a wide range of negative health effects, including heart and lung disease. Much of the blame has been pinned on gases such as carbon monoxide, nitrogen dioxide, sulphur dioxide and ozone, but the role of suspended particulate matter has been less clear.

Housing and automobiles in the United States generate almost 40% of the nation’s carbon dioxide emissions. Emissions vary with an area’s population density and weather patterns.  These in turn affect automotive and transit use, home heating, air conditioning and electricity usage.