Betting on biodiversity loss is a pretty sure thing. The earth's plant and animal species are disappearing at a sobering rate due to pressures including habitat loss, climate change, pollution and over-harvesting. Despite a few success stories and steps in the right direction, we are falling far short of stemming these losses.
Biodiversity is the entire range of biological variety in the world, including the diversity of genotypes, species and ecosystems. It can be measured on levels from DNA molecules all the way up to broad taxonomic categories such as families and phyla. Monitoring the fate of any of these aspects of biodiversity at a global scale is a daunting task. Thus, we know little about the rates and patterns of biodiversity loss or the effectiveness of global mitigation plans such as the 2002 Convention on Biological Diversity.
Dr. Stuart Butchart of the UNEP World Conservation Monitoring Centre and BirdLife International tackled the problem by assembling an international team of conservation scientists (that I was part of) to calculate trends in global biodiversity. The idea was to assemble several dozen indices that we had sound, long term data for including population trends for birds and other vertebrates and the loss of habitats such as forests, seagrass beds and coral reefs.
As we recently reported in Science magazine, our analysis indicates that biodiversity has continued to decline over the past four decades with no detectable abatement for most indices. This is largely due to increased pressures resulting from human population growth, economic development and globalization but it also seems clear that our international response to the biodiversity crisis has been inadequate.
Every aspect of biodiversity on earth is unique. The species that we have already driven extinct, from the Dodo to the Tasmanian Tiger, can never be resurrected or replaced. As a field ecologist, I have been lucky to experience and work on some truly wondrous examples of the earth's biodiversity from the tide pools of the Pacific Northwest to rainforests in Costa Rica to alpine habitats in the Rocky Mountains. The downside of my otherwise fantastic job is that I witness the degradation of nature firsthand. The coral reefs of the Florida Keys of today bear little resemblance to the underwater jungles patrolled by large sharks that I snorkeled over as a kid 35 years ago. Over the last two decades I have observed and documented striking biodiversity losses even on isolated and seemingly untouched reefs.
Understandably, my sentimental views of nature don't underlie national policy or motivate parents struggling to feed their families in poor countries. But there are far more pragmatic reasons to conserve biodiversity, the primary one being that we simply cannot live without it. Countless aspects of biodiversity make life on earth possible: coral reefs and mangroves shelter our coastal communities from storms, wetlands filter our water and sequester and store the carbon we emit, and rainforests oxygenate the air we breath and harbor plants with undiscovered biomedical value. In agriculture alone bees pollinate our crops, birds control pest insects, and invertebrates mix and aerate the soil. Farming would not be economically viable if farmers had to pay for these services provided for free by the earth's biodiversity. In nearly all cases, the preservation of biodiversity is in sync with our economic interests. Over its lifetime, a whale is far more valuable as a tourist magnet than as sushi or canned meat in Tokyo. Every species that goes extinct and every habitat that disappears represents a socioeconomic loss that would make any hard-nosed financial planner cringe.
Despite the bleak picture, there are still many near-pristine places, like the unique Galapagos Islands ecosystem with incredible amounts of biodiversity that can still be conserved. Most of the world's species, including some on the brink of extinction, can be saved with a mixture of international leadership, pragmatic decision-making and modest capital investment. And unlike other political or economic opportunities, this really is one that we can't afford to pass up.