To be stable and functional, an ecosystem requires balance. Too much fluctuation in any of a number of variables can result in runaway extremes of temperature, acidity, drought, and other conditions that will leave the system unfit for most of its living inhabitants. (Just look at what happened in the Biosphere 2 experiment when researchers couldn't manage to maintain a healthy balance of oxygen and carbon dioxide.) Rapid change within an ecosystem almost always leads to mass extinctions.
Our Earth is an ecosystem, the largest and most complex in the known universe. We've been lucky over the last 10,000 years or so to have experienced a period of significant stability, a time when temperatures, precipitation levels, and atmospheric composition have stayed remarkably consistent. This Holocene Epoch, as it is called, has allowed human civilization to arise and flourish.
Unfortunately, the rapid growth of our cities and our industries is producing an impact that threatens to destabilize the complex ecosystem that supports us. We may be reaching a tipping point where we will be unable to control the runaway effects that could undo all that we've managed to build in the last ten millennia.
Human civilization has had a stable childhood. Over the past 10,000 years, as our ancestors invented agriculture and built cities, the Earth remained relatively stable. The average global temperature fluttered slightly, never lurching towards a greenhouse climate or chilling enough to enter a new Ice Age. The pH of the oceans remained steady, providing the right chemical conditions for coral reefs to grow and invertebrates to build shells. Those species, in turn, helped support a stable food web that provided plenty of fish for us humans to catch. The overall stability of the past 10,000 years may have played a big part in humanity’s explosion.
Now, ironically, civilization has become so powerful that it can reshape the planet itself. “We have become a force to contend with at the global level,” as Johan Rockstrom of the Stockholm Resilience Center in Sweden, puts it. Humans have changed the chemistry of Earth’s oceans, lowering their pH and causing ocean acidification. We are shifting the composition of the atmosphere, raising levels of carbon dioxide higher than they’ve been in at least the past 800,000 years.
That's Carl Zimmer, in an article for NOVA Science. He continues:
A number of scientists have warned in recent years that if we keep pushing the planet this way, we will cause sudden, irreversible damage to the systems that made human civilization possible in the first place. Typically, they’ve just focused on one of these tipping points at a time. But in today’s issue of the journal Nature, Rockstrom and 27 of his fellow environmental scientists argue that we have to conceive of many tipping points at once. They propose that humans must keep the planet in what they call a “safe operating space,” inside of which we can thrive. If we push past the boundaries of that space -- by wiping out biodiversity, for example, or diverting too much of the world’s freshwater -- we risk catastrophe.
Ominously, we have already moved past three of these tipping points.
One of the key tipping points those scientists highlight is biodiversity loss: the depletion of species through mass extinction.
That's the subject of a recent opinion piece in the Los Angeles Times by Jeff Corwin, the author of 100 Heartbeats, The Race to Save Earth's Most Endangered Species. He says:
There is a holocaust happening. Right now. And it's not confined to one nation or even one region. It is a global crisis.
Species are going extinct en masse.
Every 20 minutes we lose an animal species. If this rate continues, by century's end, 50% of all living species will be gone. It is a phenomenon known as the sixth extinction. The fifth extinction took place 65 million years ago when a meteor smashed into the Earth, killing off the dinosaurs and many other species and opening the door for the rise of mammals. Currently, the sixth extinction is on track to dwarf the fifth.
Corwin points out that there are many factors contributing to this dangerous decline in diversity, including overpopulation, loss of habitat, global warming, and species exploitation. The black market for rare animal parts is the third-largest illegal trade in the world, outranked only by weapons and drugs, he says.
He emphasizes that our concern should extend well beyond a few beloved species:
It's important to understand that this is not just a race to save a handful of charismatic species -- animals to which we attach human-inspired values or characteristics. Who wouldn't want to save the sea otter, polar bear, giant panda or gorilla?
These striking mammals tug at our heartstrings and often our charitable purse strings. But our actions need to be just as swift and determined when it comes to the valley elderberry longhorn beetle or the distinctly uncuddly, pebbly-skinned Puerto Rican crested toad or the black-footed ferret, whose fate is inextricably intertwined with that of the prairie dog. The reality is that each species, no matter how big, small, friendly or vicious, plays an important and essential role in its ecosystem. And we're in a race to preserve as much of the animal kingdom as possible.
Meanwhile, around the planet there are massive die-offs of amphibians, the canaries in our global coal mine. When frogs and other amphibians, which have existed for hundreds of millions of years, start to vanish, it is a sign that our natural world is in a state of peril.
Bat and bee populations are also being decimated. Without bees, there will be no pollination, and without pollination, the predator that is decimating these other species -- humankind -- will also be headed toward its own extinction. Yes, there is a certain irony there.
A major contributing factor to the shocking rate of species depletion that we're witnessing is rapidly increasing ocean acidification. And, once again, this changing variable is largely a result of human activity:
Oceans absorb about 25 percent of the world's greenhouse gases pumped into the atmosphere from human activities each year, says a new U.N. report released at the Copenhagen talks this week. That helps slow global warming in the atmosphere, the focus of the Copenhagen talks.
But carbon dissolving in oceans also forms carbonic acid, raising waters' acidity that damages all manner of hard-shelled creatures, and setting off a chain reaction that threatens the food chain supporting marine life.
By 2100, the report said, some 70 percent of cold water corals -- a key refuge and feeding ground for commercially popular fish that also are food for seals and otters -- will be exposed to the harmful effects.
Ocean acidity could increase 150 percent just by mid-century, according to the report by the Secretariat of the U.N. Convention on Biological Diversity.
"This dramatic increase is 100 times faster than any change in acidity experienced in the marine environment over the last 20 million years, giving little time for evolutionary adaptation within biological systems," it said.
The average acidity of oceans' surface water is estimated to increase measurably by the end of the century and will affect marine life, according to Peter Brewer, a senior scientist at the Monterey Bay Aquarium Research Institute.
"The total quantity of carbon dioxide that we've put into the oceans today is around 530 billion tons," Brewer told journalists on a fall fellowship program with the Honolulu-based East-West Center. "Now, it's going up at about 1 million tons an hour. You can't keep doing that without it having some impact."
Dead Sea
Here's the real problem.
If we can't succeed in slashing our global carbon dioxide outputs within the next decade or two, then global warming could reach a tipping point where the only way to prevent the worst impacts of climate change -- droughts, floods, killer storms, pestilence, crop failures, pandemics, disastrous sea level rise, and hundreds of millions of climate refugees -- will be seen as many to be an all-out effort at geoengineering.
And the irony is that the most popular schemes for geoengineering -- those most likely to be attempted -- will either do nothing to reduce ocean acidification, or in some cases could even make it worse. We're damned if we do and damned if we don't.
Techno-rapturists among our reading audience might be quick to respond with glib answers about miraculous nanotechnology solutions that are just around the corner, or the promise of a superintelligent friendly AI who can take over everything and solve all our troubles just like Daddy would.
Unfortunately, all those naive fantasies of easy fixes run smack up against the actuality of human politics, economics, greed, inertia, and the seemingly intractable difficulties of producing sudden dramatic improvements in the morass of a messy real world.
The best we can hope for is significant, meaningful, but incremental change. It's not as alluring as dreams of utopia, but if we want a better future for ourselves and our children -- or, more realistically, a future that's not considerably worse -- we have to focus on what can be done and get to work on that.