Every living thing—plants, animals, microorganisms—shares an extraordinary history that stretches back 4 billion years to the origins of life on Earth. Although countless species have come and gone in that grand interval, today we share the planet with tens of millions of species, simultaneously shaping the Earth’s very form and function. Akin to the miracle of loaves and fishes, living things have turned, and continue to turn, stone into soil. The presence of life on Earth is so robust that it has markedly affected the composition of our atmosphere and continues to do so. Indeed, the atmospheric carbon dioxide concentration rises and falls in an annual rhythm tied to the seasons by biological activity—almost as if the planet itself was a living organism.
When I studied biology in high school, the tree of life consisted basically of two sturdy trunks, one the animals and the other the plants, with some “lesser” things around its base. Today, with 1.9 million species so far discovered and the ongoing mapping of their phylogenetic relationships, that tree resembles something more like a spreading bush with three terminal twigs at one end that represent animals, plants, and fungi. All the rest consists of different microorganisms, many representing forms dating from the early history of life on Earth. Many of these microorganisms have strange appetites and strange metabolisms. In a sense they are the real “environmental extremists.”
Because each species represents a set of biological solutions to problems particular to its own survival, the diversity of Earth’s organisms is, in essence, an incredibly valuable reference library with a countless number of volumes, most of them yet to be cataloged. Societies, excepting the most despotic, place enormous value on libraries and never justify them in terms of their economic benefit.
The benefits of maintaining biodiversityThere are many reasons to value biological diversity as we do any great library. The life sciences are transformed regularly by the discovery of previously unknown biological properties in organisms that had been considered esoteric or lacking in utility. A case in point is the antitumor drug Taxol (paclitaxel), which was first isolated from the Pacific yew, then considered a trash tree in forests of the Northwest. Oil-eating bacteria, which are natural denizens of the oceans, went to work after the Deepwater Horizon oil spill and offer the potential to improve industrial and environmental clean-up. And perhaps the greatest example to date is the heat-resistant enzyme derived from an extremophilic bacterium living in a Yellowstone hot spring, without which there would be no polymerase chain reaction (PCR). As a consequence of the enzyme’s use in PCR, for much of diagnostic medicine it is no longer necessary to culture the offending microbe to identify the disease agent. The technique has revolutionized forensic medicine, much to O.J. Simpson’s chagrin. It has enabled all kinds of new scientific work, including genomics and the entire Human Genome Project. The benefit to society must already be on the order of at least a trillion dollars.
Unlike most scientific fields, conservation biology rests on an explicit ethical principle: biological diversity is valuable in itself, irrespective of the economic or practical value of a particular species.
—Edward C. Wolf, “Tropical Biology: A Legacy of Neglect,” The Scientist, June 29, 1987
The third Global Biodiversity Outlook, produced for the 2010 International Year of Biodiversity, tells us this value is severely threatened. Extinction rates on land and in the seas are soaring—at perhaps 1,000 times normal levels. There is ever more forest clearing and grassland degradation. Most of the major predatory fish of the oceans and most major traditional fisheries are decimated, and atmospheric CO2 is causing the oceans to become more acidic.
Climate change is making itself felt forcefully. Ecosystem failure is occurring worldwide: as warming sea temperatures cause coral reefs to bleach, their diversity, productivity, and value to coastal communities is crashing. Coniferous forests of western North America are experiencing widespread tree mortality caused by native bark beetles, which thrive in summers that are now longer and winters that are warmer. The Amazon forest is fast approaching a tipping point where deforestation combined with other factors could lead to dieback in the south and southeast. Not only must deforestation be stopped, but substantial reforestation must follow.
Roughly half of the excess atmospheric CO2 that is driving climate change comes from the destruction and degradation of ecosystems over the past three centuries, which means biology and its diversity could actually be utilized to help reduce the atmospheric CO2 burden. Because life in all its diversity is built of carbon, ecosystem restoration (reforestation, grassland recovery, agro-ecosystems that accumulate rather than lose soil carbon) could remove a significant amount of carbon from the atmosphere. That doesn’t solve the entire carbon dioxide problem, but it would lower the climate-change threat to the living planet while simultaneously fortifying ecosystems and ensuring the future of the diverse life of the planet.
In the end, the choice is whether to embrace nature and its miraculous diversity or to suffer the consequences. Those consequences are vividly laid out on the island of Hispaniola, where Columbus stopped during his first voyage: the Dominican Republic is verdant and relatively prosperous; Haiti has been stripped of most of its ecosystems and biodiversity and is what a Trinidadian colleague terms “the unthinkable experiment no scientist would be allowed to conduct.” Surely the choice is obvious.Thomas E. Lovejoy is University Professor of Environmental Science and Policy at George Mason University, Biodiversity Chair at the Heinz Center for Science, Economics and the Environment, and chair of the Global Environment Facility’s Scientific and Technical Advisory Panel.