It’s an amazing fact that the contemporary world is marked by a growing number of problems that are genuinely global in scope. Some of these problems even have existential implications for the survival of human civilization -- yet instead we spend too much time discussing smaller threats, including North Korea, ISIS, Oregon militias and even Sarah Palin. One such problem is anthropogenic climate change — a catastrophe whose effects are anticipated to be “severe,” “pervasive” and “irreversible.” Based on the best current science, climatologists anticipate more extreme weather events, melting glaciers, sea level rise, megadroughts, desertification, deforestation, food supply disruptions, famines, infectious disease, mass migrations, social upheaval, economic distress, and political instability. While there’s a small (but real) chance that a runaway greenhouse effect could turn Earth into an unlivable cauldron like our planetary neighbor Venus, climate change is perhaps best described as a “conflict multiplier” that will exacerbate existing geopolitical problems and introduce brand-new struggles between state and nonstate actors vying for control of habitable land and dwindling resources.
But climate change isn’t the only problem of this sort. In fact, for many who spend their lives studying environmental issues, it can be frustrating to see climate change — a highly contentious issue among non-experts, despite a scientific consensus about its reality and causes — dominate the public discussion. The fact is that biodiversity loss constitutes an equally worrisome (albeit related) threat to the future of humanity. Few people today realize just how dire this situation has become as a result of human activity, or how severe the consequences could be if we continue to prune the evolutionary Tree of Life with reckless abandon.
Consider some cold hard facts. According to the 3rd Global Biodiversity Report (GBO-3), the total population of vertebrates — a broad category that includes mammals, birds, reptiles, sharks, rays and amphibians — living within the tropics declined by a shocking 59% from 1970 to 2006. Take a moment to let this sink in. In only 36 years, more than half of the vertebrate population between the Tropic of Capricorn and the Tropic of Cancer disappeared. The report also found that the abundance of vertebrates living in freshwater environments fell by 41 percent since 1970, farmland birds in Europe declined 50% since only 1980, birds in North America declined by 40% between 1968 and 2003, and nearly 25 percent of all plant species — the foundation of the food chains upon which we depend — are currently “threatened with extinction.”
Even more, the GBO-3 states that “42% of all amphibian species … are declining in population.” This is especially unnerving because amphibians are “ecological indicators,” meaning that they’re more sensitive to environmental perturbations than other organisms, sort of like the canaries that miners used to bring underground with them. The idea was that, given their heightened sensitivity to carbon monoxide, methane, and other gases, canaries would keel over before the miners, thus warning them that high levels of dangerous gasses are present. In the case of amphibians, the metaphorical “canary in the coal mine” is convulsing — this is what the GBO-3 confirms. Yet humans around the world are either unaware of this situation or satisfied to watch them wriggle, when we should be taking immediate action to save the lives of ourselves and future generations.
But the GBO-3 isn’t the only comprehensive report with rather bleak results about Earth’s living systems. Another study called the Living Planet Report recently found that the global (not just tropical) population of vertebrates between 1970 and 2010 fell by an incredible 52%. Again, pause for a moment to reflect on this figure. The report adds that within this interval of time — only four decades — freshwater species declined by 76%, and both marine and terrestrial species waned by 39%. It concludes with the warning that, given our consumerist economy that promotes the endless acquisition of products over the conservation of nature, humanity would “need 1.5 Earths to meet the demands we currently make on nature.” Still other studies have arrived at similarly dismal conclusions. For example, scientists report that 48% of all the world's primates, 20% of all reptile species, 50% of all freshwater turtles, and 68% of plant species (as of January 2016) are threatened with extinction.
Turning now to the ocean, one finds an equally grim situation. Consider a recent count by the marine biologist Robert Diaz and his colleagues that identifies more than 500 “dead zones” around the world, resulting from human activities. A dead zone is a region of water in which algae feed off of nutrient pollution, bloom, die, and then suck up all the water’s oxygen as they decompose. Consequently, marine creatures that can’t escape the area suffocate, as if a plastic back were put over their heads and tied shut. The consternating fact is that from Lake Erie to the Baltic Sea, the Gulf of Mexico to the coastal waters of New Zealand, dead zones are growing in both size and number. In some cases, these uninhabitable regions can be extraordinarily large. The biggest known dead zone today, in the Baltic Sea, is roughly 27,000 square miles large — or slightly smaller than the state of South Carolina.
Another problem facing marine life stems from the acidification of the ocean. The fact is that over the past two centuries, the ocean has become 25% more acidic, mostly as a result of absorbing carbon dioxide in the atmosphere from the burning of fossil fuels. This is bad because an increasingly acidic (and warm) ocean accelerates the destruction of coral reefs, which certain species of fish and invertebrates depend upon for their survival — not to mention that “coral reefs are a valuable source of pharmaceutical compounds.” Today, about 10% of all the coral reefs around the world have been transformed into underwater ghost towns, and about 60% are in danger of dying. In fact, the oceans are becoming so acidic from absorbing carbon dioxide that the shells of “tiny marine snails that live along North America’s western coast” are literally dissolving in the water. It’s unfortunate but the oceans are dying and the consequences could be severe. As a 2006 paper published in Science notes, based on current trends there will be virtually no more wild-caught seafood by 2048. Sorry, future generations.
What does this all add up to? Well, according to a 2015 article published in Science Advances, biodiversity loss has been so profound and widespread that we may be in the early stages of the sixth mass extinction event in the entire 3.5 billion year history of life on Earth. This, once more, demands a moment of quiet reflection. (The last mass extinction occurred about 65 million years ago and wiped out nearly all of the dinosaurs; a few survived and evolved into birds.) The study shows that even using the most optimistic possible assumptions, recent rates of species loss are vastly elevated relative to the natural background rate. As other scientists have suggested, the rate of extinction — which happens normally in nature at a certain frequency but can be helped along by human activity, as was the case with the dodo — may have increased up to 10,000 times. The resulting die-out is called the Holocene extinction event — a term to remember as we slide into the Anthropocene.
Along these very lines, yet another study published in 2012 and authored by over twenty scientists argues that we may be on the verge of a catastrophic, irreversible collapse of the global ecosystem. The authors single-out factors like human population growth, resource over-consumption, ecosystem fragmentation, and climate change as the primary causes of this plight. What’s most unsettling about the paper’s findings is that there might not be any immediate warning signs that a global ecosystem collapse is about to occur. The idea is that nature has certain “critical thresholds” that, once crossed, result in sudden and severe changes. By analogy, one can imagine slowly deforming the shape of a dry piece of spaghetti. As the noodle bends more and more, it nonetheless remains intact. But then, in a moment and without any warning it snaps into (three) pieces. The global ecosystem could behave exactly like this: once a “tipping point” is reached, the system collapses and cannot be restored to its original state.
Now, having said all this, I’ll admit that the danger of biodiversity loss may sound overblown and alarmist. Most people look around at the world and don’t observe any obvious signs of an environmental disaster unfolding in real time. So what’s the worry? Well, just because the non-expert (with little or no knowledge of how ecosystems actually work) can’t see the catastrophe doesn’t mean that it’s not real. After all, physicists tell us that 99.9% of matter is empty space, yet no amount of squinting will reveal this fact to the naked eye. This is precisely why we need scientific research to show us the truth — and scientific research is precisely what I presented above.
Beyond this, it’s absolutely crucial to recognize that there’s a huge difference between being an alarmist and being alarmed — two attitudes often confused in public “debates” about environmental issues. Alarmism is what happens when the degree to which one is afraid goes beyond the strength of the relevant evidence. In other words, to adapt a phrase from David Hume, wise people always proportion their fears to the best available evidence, considered as a whole. It follows that there’s nothing wrong with being afraid, or even terrified. What matters is that one’s fears accurately track the totality of evidence, as new research uncovers new facts about the abundance of organisms in the world. This is basic epistemology, yet it’s a hard concept for many people to grasp — and even harder for most to honestly put into practice.
So, the danger of biodiversity loss isn’t overblown alarmism. There really is strong evidence, uncovered by scientists from around the world, that suggests we should be very worried about the future. Indeed, like climate change, biodiversity loss is a conflict multiplier that will significantly inflate the probability of wars and terrorist attacks. This is why solving the problem ought to be a top priority for the world’s biggest superpower — the United States — in 2016. In a global village that’s projected to house 9.3 billion people by 2050, it’s more important than ever before that people recognize the ongoing loss of biological diversity and work to prevent the Holocene extinction event from turning into a full-blown existential nightmare.
This article borrows from my forthcoming book, "The End: What Science and Religion Tell Us About the Apocalypse" (Pitchstone Publishing).