Ecology

According to the Environmental Protection Agency, urbanized land in the United States increased by 48% from 1982 to 2003 and now covers more than 100 million acres. This expansion of cities and suburbs has had significant impacts on wildlife through habitat loss, pollution and the introduction of nonnative species.

Land use in the United States has always been marked by change — forest has become cropland and then returned again; towns have grown in rural areas only to disappear; cities have grown, suburbs have spread.  In the last 25 years, however, change has accelerated in ways that depart from previous trends, even as the stakes have gotten higher — land use can have real effects on climate change, wildlife habitat and now even energy production.

Overfishing is a problem that has become more acute as global populations have increased, technology has improved and the environment has degraded. Until recently most management efforts have focused on limiting fishing days or areas, yet fishing stocks have continued to decline precipitously.

Humans have been working to increase crop yields since agriculture began, and major advances were made during the “green revolution” that began in the 1940s. Genetic engineering has been portrayed as the latest step in this process.  The majority of approved engineered seeds are aimed at decreasing losses due to pests and weeds; a primary example is Bt corn, produces a bacteria that kills the European corn borer and other insects.