In his book The World Without Us, journalist Alan Weisman describes several nasty legacies of human activity that could wreak havoc on the world if we all disappeared tomorrow. They represent the beginning of a list of pollutants I believe we should try to clean up regardless of our own future, thus helping in the realization of an ideal world.
Near the top of the list would be nuclear material, most of which will take many thousands of years to cease being radioactive enough to cause near-immediate death, cancer, or dangerous genetic mutations. In addition to many tons of material currently used in nuclear power plants and weapons that could be exposed to the environment when the systems protecting them fail, there is a growing amount of “waste” that has been properly or improperly isolated or shielded.
Of more immediate danger is the carbon dioxide we continue to add to the atmosphere; which, in addition to altering the climate, is more insidiously acidifying and reducing the oxygen in the oceans (destroying the base of the food chain and potentially enabling sulfur bacteria to damage the ozone layer and make the air un-breathable). Global warming could drastically intensify if increased temperatures cause permafrost to melt, exposing huge amounts of the methane, which is a far more effective greenhouse gas.
Persistent organic pollutants (“POPs”) such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and dioxins are nearly indestructible toxic substances that have negative effects even in small doses and are now found almost everywhere in the world. POPs are products of industrial organic chemistry that includes creation of plastics, aiding agriculture (pesticides and herbicides), and weapons (Agent Orange). The toxic effects of POPs may be enabled by the ingestion of tiny particles of plastic, the result of degradation of our plastic products by natural forces and the deposition of much of this waste into the oceans by wind and river runoff.
Heavy metals such as zinc, copper, lead, and chromium are, in high enough concentrations, toxic to humans and other animals. They are integral parts, or emitted by, much of what our economies produce, including power plants, cars, and fertilizers; and they are likely to be around for thousands to tens of thousands of years.
Weisman’s research suggests that Nature will eventually adapt to most of these pollutants, though there will be much pain and death along the way. He concludes his book with one major suggestion for dealing with most of the ills we face: reducing the world’s population humanely by limiting the birth rate to one child per mother. Fewer people would produce less waste and give the biosphere room to recover from our assault.