by Whit Gibbons

December 18, 2011

Q. A few years ago you conducted a poll of ecologists to identify the top 10 causes of environmental problems. Would you comment on your original list in the context of today's world?

A. Listing the top 10 sources of environmental problems is one way to put them in perspective. The original list included seven that were somewhat interchangeable as to how they should be ranked. One, two, and three were the same in almost everyone's list, although not always in the same order. Following is the original ranking of environmental problems, in order of increasing concern, with my current comments.

10. Invasive plants and animals. Recently reported problems of fire ants around the world, ambrosia beetles that infect red bay laurels, and pythons in the Everglades confirm the ongoing problem with introductions of exotic species.

9. Global climate change. A problem today is the impaired ability of some native species to respond appropriately to climate change as they have in past millennia because humans have compromised natural environments. "Global warning" has become such a volatile issue that debates between advocates and disbelievers about potential impacts and solutions are seldom productive. Nonetheless, numerous credible scientific studies have documented changes in recent decades.

8. Degradation of marine habitats. The oceans are huge, but they cannot withstand the current rate of worldwide pollution and unsustainable harvesting. Reports of commercial extinction of once common fish such as cod and grouper and the decline of coral reefs around the globe focus attention on the severity of the problem.

7. Air pollution. Uncontrolled releases by industry and the excessive use of fossil fuels have led to acid rain, dissolution of the ozone layer, smog, and the general degradation of "clean air."

6. Unsustainable agriculture. Humans are dependent on food production, but agricultural siltation, pesticide runoffs, and loss of natural habitats are constant threats to a healthy environment. "Dead zones" of oxygen-depleted waters in the Gulf of Mexico and other bodies of water are attributed primarily to the excessive use of chemical fertilizers by agricultural systems.

5. Threat of disease. This category in the previous list focused on impacts of human diseases. But disease is also an environmental concern for countless native species in many regions of the world. Included among the devastating invasive diseases is the Asian fungus that drove American chestnuts almost to extinction. Chytrid fungus, believed to have been introduced from Africa, is held responsible for widespread die-offs of frogs in many parts of the world.

4. Freshwater quality and quantity. Sewage from cities and unregulated releases from industrial and agricultural sites collectively exacerbate the worldwide problem of pollution in freshwater ecosystems. Saltwater intrusion resulting from overuse of groundwater in many coastal regions is a looming specter. Water wars between states are now a reality in the U.S. West and Southeast following long-term droughts.

3. Habitat loss, fragmentation, and degradation. The loss of natural habitats because of human development and deforestation continues to be the major cause of the decline in biodiversity nationally and globally. Many species, especially in tropical rain forests, are on an inexorable path toward extinction because their native habitats have been destroyed or despoiled.

2. Human overpopulation. Unchecked human population growth, leading to overconsumption and associated world poverty, is one of the top culprits of environmental problems. Virtually every problem from 3 through 10 can be attributed to there simply being too many people for the available resources. At least in part because of religious or cultural constraints, most political leaders do not address the issue of birth control on a global scale, ensuring that most of our environmental problems will worsen before they get better.

1. Apathy. I still consider this our number one environmental problem. As proof, you need look no further than the majority of U.S. politicians, who seldom acknowledge, let alone propose solutions to, environmental problems. Sounds like apathy to me. Unless they are ignoring the public good for their own personal gain--which would be even worse than apathy.

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