As human populations and natural resource demands grow, natural ecosystems get squeezed. The following is a partial list of some of our worst environmental nightmares. These problems do not exist in isolation, but often cause or result from others, sometimes in unpredictable ways.
Loss of Biodiversity
Biodiversity is the variety and abundance of life forms on Earth. Diversity gives ecosystems stability and provides us with life support in the form of oxygen, clean water, food, and materials of all sorts. As distinguished Harvard conservationist E.O. Wilson says, if we don't halt the extinctions, within the next century we will have caused sufficient biological impoverishment to call our time "the Eremozoic era, the Age of Loneliness."
Habitat Destruction
Biologists generally recognize habitat loss as the leading cause of species declines worldwide. Losses come from direct removal, such as forest clear cuts, while others occur as a result of processes that may be indirectly caused by man, such as inundation of coastal habitats caused by sea level rise from global warming.
Global Warming
Global warming is the gradual heating of Earth resulting from increased greenhouse gases, or GHG, in the atmosphere. Carbon dioxide and methane are examples of GHG, which cause a heating effect that makes the Earth habitable. However, industrialization has increased GHG through the burning of fossil fuels, particularly coal. According to the Pew Center for Global Climate Change, "Today's carbon dioxide levels are substantially higher than anything that has occurred for more than 400,000 years."
Invasive Species
Scientists often list invasive species as the second greatest contributor to extinctions worldwide. Invasive species have been introduced, intentionally or accidentally, into areas where they are not native. Lacking predators and other restraints on their growth, they spread aggressively,to the detriment of native species. Familiar examples of such exotics include the kudzu vine in southeastern forests and zebra mussels in northern waterways.
Ocean Plastics
Since discovering a trash vortex twice the size of Texas in 1997, the Algalita Foundation has documented the growing plastic burden in the world's oceans. Plastics break down into tiny bits forming a "soup" in which tiny plastic particles may outweigh plankton, the base of the marine food chain, by a factor of six.
Water Pollution
Water pollution comes from factory discharges, urban and agricultural runoff. Depending on its source, pollution runs the gamut from deadly toxins to human or animal waste to pesticide-laden sediments carried in agricultural irrigation water. Pollutants may infiltrate groundwater, making potable water permanently undrinkable.
Air Pollution
Chemicals discharged into the air by smokestacks, vehicles, and planes cause a variety of air pollution problems. Three of the most well-known include smog, acid rain, and global warming. Smog directly impacts human lungs. Acid rain can kill forests and aquatic life. Global warming contributes to sea level rise, droughts, and biodiversity loss. All of these problems share one thing in common: they come from burning fossil fuels.
Poaching
Hunting wild animals illegally for folk medicines, ivory, teeth, trophies or meat is a growing problem that is causing the decline of wildlife species around the world. Research has shown the bushmeat trade is a growing problem that can cause cascading effects through the ecosystem. In China, tigers parts are illegally imported to treat ailments such as headaches, while African elephants are still endangered by the outlawed ivory trade.
Overfishing
Once viewed as limitless, the oceans are under siege. Some of the world's most productive fisheries, such as New England cod, have collapsed because an overly large, highly efficient world fishing fleet is systematically depleting fish species. Moreover, high levels of bycatch in some fisheries lay waste to habitats and needlessly kill nontarget species.
Genetic Pollution
Genetically modified or GM foods come from genetically modified crops. The problem with modifying living, reproducing species is that completely novel genes inserted into their DNA can spread to other species in an ecosystem. Organic farmers can lose their organic status if their crops cross pollinate with those that have been genetically modified. Bt corn, a GM crop, may be contributing to declining Monarch butterfly populations.
Member Comments