A few of what were once considered imminent environmental catastrophes now seem like memories from a bygone era. Whether the problem is solved, the public loses interest, or there was never really much to fear, environmental causes can sometimes simply fade away.
The Ozone Hole
What was the problem? Scientists had warned for years that chlorofluorocarbons (CFCs), used in refrigeration and aerosol sprays, could deplete the ozone layer that surrounds the Earth and absorbs dangerous UV rays. They were right, but it wasnt until the hole over Antarctica was discovered in 1985 that the issue burst into public consciousness as what the U.S. Environmental Protection Agency (EPA) called a megaproblem. Dire warnings about the consequences, particularly rising rates of skin cancer, prompted governments to crack down on CFC use around the world.
What happened to it? Its healing. Since the 1987 signing of the Montreal Protocol, which strictly regulated the use of CFCs, the hole has stopped widening and might even be shrinking. It is now hoped that the hole will fully heal in the next 60 years. A recent study also shows that improvements in the ozone layer could help slow the effects of global warming in the Antarctic.
Could it come back? Unlikely, if the ban on CFCs remains in place. However, the chemicals brought in to replace them can have their own damaging environmental effects.LIU JIN/AFP/Getty Images
What was the problem? Acid rain refers to precipitation of any kind with high concentrations of nitric and sulfuric acids. It is caused by the burning of fossil fuels, particularly coal and gasoline. High acidity levels in rain can disrupt freshwater ecosystems, damage trees and soil, and even cause corrosion of buildings and statues. The terrifying-sounding phenomenon regularly made headlines throughout the 1980s and early 1990s.
What happened to it? Its improving, for the most part. The now ubiquitous use of catalytic converters in cars and the switch to cleaner forms of coal and natural gas have helped bring down acidity levels throughout Europe and North America. The EPA predicts that the effects of acid rain in the northeast United States will soon be virtually eliminated, thanks to the countrys 1990 Clean Air Act. In Europe, acid rain levels have fallen nearly 73 percent since 1980.
Could it come back? Absolutely. The international shipping industry continues to rely on high-sulfur fuels, but the worst offender by far is China, where factories and power plants continue to burn coal at an alarming rate. In 2006, it was estimated that one third of Chinas territory was affected by acid rain. The countrys neighbors are feeling the effects as well.David Silverman/Getty Images
Save the Whales
What was the problem? Perhaps no environmental issue has ever captured the publics attention quite as much as the plight of whales. Overhunting, food supply disruption, and global warming decimated global whale populations in the 20th century. In the 1960s, the population of humpback whales fell below 2,000. Antarctic whales were nearly wiped out. The International Whaling Commission banned the hunting of whales in 1986, but illegal whale hunts continue to this day. Japan continues the controversial practice of scientific whaling, which kills up to 600 whales per year.
What happened to it? Some whales are recovering. Humpback populations have increased to about 20,000, and blue whales have bounced back to about 1,500. Other species have not fared so well. Despite being taken off the endangered species list, Pacific gray whales have seen a recent spike in deaths, possibly due in part to global warming. Despite intensive human efforts to protect them, North Atlantic gray whale populations have not recovered, thanks largely to shipping and fishing nets in their habitat. Only about 300 are still alive. Though save the whales was a rallying slogan for the emerging environmentalist movement of the 1970s, public interest has waned as measures to protect them become less a matter of blocking whaling ships than addressing larger environmental concerns.
Could it come back? You bet. Because of the recovery of humpback and blue whales, whaling countries such as Japan and Iceland are lobbying for the international ban to be lifted. If whaling were resumed at anything near its previous levels, it could be catastrophic for a species thats just barely beginning to recover.Win McNamee/Getty Images
Bald Eagle Extinction
What was the problem? At one point, it appeared quite likely that the United States would kill off its own national symbol. The bald eagle was threatened by hunting, deforestation, and poisoning from the pesticide DDT. More than 100,000 bald eagles were killed in Alaska between 1917 and 1953, and in the continental United States, there were only 417 breeding pairs left by 1963. In response to the crisis, the eagle was placed on the endangered species list in 1967 and DDT was banned in 1973.
What happened to it? Theyre back! The recovery of the bald eagle is one of the great success stories of American conservationism. Thanks to the DDT ban and protection of their habitat, there are now nearly 10,000 breeding pairs in the lower 48 states. The bald eagle was taken off the endangered species list in 2007.
Could it come back? Maybe. Its still illegal to hunt bald eagles, but now that they are off the endangered species list, their habitats are no longer subject to the same level of protection as before. Eagles still face dangers from deforestation and development.PASCAL PAVANI/AFP/Getty Images
Genetically modified food
What was the problem? Ever since Frankenfoods came on the market in the 1990s, the concept has made a lot of people very nervous. Genetically modified (GM) foods are created when the genetic structure of an organism is artificially modified or implanted with the DNA of another species. Food producers use genetic modification to increase yields or make foods more resistant to insects or viruses. Particularly in Europe, GM food has come under great scrutiny due to fears about its safety and environmental impact. Tight import restrictions on GM foods remain in place throughout the European Union. In the United States, the backlash has never been as strong, but some environmentalists continue to push for labeling of GM products, at a minimum.
What happened to it? Two words: food crisis. With food prices skyrocketing around the world, its getting harder for skeptical governments to justify restrictions on a technology that could substantially help alleviate world hunger. The shift has been particularly evident in the developing world, where more countries now grow GM crops than in the developed world. Even in hostile Europe, the climate could be changing. Six European countries planted GM crops for the first time in 2007, and this month, British Prime Minister Gordon Brown suggested that the EU reconsider its stance on genetic modification in light of soaring food prices.
Could it come back? It never went away completely. Scientists have been unable to show any health risks from genetic modification, but countries such as France and Austria continue to be suspicious of the technology. Environmental groups like Greenpeace and Friends of the Earth also continue to push against any loosening of the EUs policy.