Up to now I have been talking about the main inputs to our industrial society, namely, food, energy, and water, all of which interact, influence, and feed off each other to form complex relationships that support our civilizational. E.g. a shortage of water can have an impact on our ability to grow food. It can also impact our ability to obtain energy, whether via a reduction in corn to produce ethanol, due to low river levels inhibiting transportation of coal, a reduction in power plant cooling capacity, or a limit on hydraulic fracturing. Burning fossil fuel energy increases atmospheric CO2, thereby increasing climate change, and ultimately increasing likelihood of drought and water shortages, further feeding the cycle. Another example: an energy crisis can lessen our ability to grow food by halting transportation, and increasing prices to the inputs of industrial agriculture.
All of these relationships come together to create an intricate industrial system, involving economic, geographic, and thermodynamic forces, impacting anything from small time farmers, to stock markets. Despite this complexity, the system is vulnerable due to the chokepoints of the basic inputs of food, energy, and water it relies on.
Today I am going to discuss another complex set of systems that have interdependent relationships and multiple feedback mechanisms. As you have probably guessed from the title, I am referring to ecosystems. Specifically, I want to focus on biodiversity, and how human activity is threatening the complex communities all life is based in.
We know about Grizzlies, Wolves, Condors, and Bison. We know about the danger Polar Bears are facing. How about others?
- Wild salmon in California, Oregon, Washington, Idaho, and southern British Columbia have been on a 160+ year downward trend and are now at very low levels.
- Five butterfly species have vanished.
- Caribbean coral reefs are on the verge of collapse, with less than 10% of the reef area showing live coral cover.
- White-nose syndrome (WNS) is associated with the deaths of at least 5.7 million to 6.7 million North American bats.
- Calculations based on extinction rates suggest that the current extinction rate of amphibians could be 211 times greater than the background extinction rate and the estimate goes up to 25,000–45,000 times if endangered species are also included in the computation.
- Many experts estimate orangutans could be extinct in the wild in less than 25 years.
When I was a kid, I would roam our pasture catching fireflies and collect them in glass jars. I’m not sure if children are still able to do this, because firefly populations are disappearing around the world.
There have been several recent spontaneous die-offs of various species of fish, bird, and mammals with mysterious causes, including 83,000 drum fish in Arkansas, 4500 blackbirds in Arkansas, 877 dolphins in Northern Peru, 2300 seabirds in Chile, and Starfish in multiple geographic areas. (To be clear, I’m not making the case that all of these events are related or human caused)
Everyone probably already knows by now about Honeybee decline and Colony Collapse Disorder. If not, I encourage you to check out the documentary More Than Honey, which is available on Netflix.
This leads me into the concept of Keystone Species. All of these species I’ve listed are just scratching the surface of populations in decline. Each individual listed is food for some other species, and contributes to the community it participates in. If Grizzlies eat Salmon, and Salmon are in decline, Grizzlies might have a problem finding food. Each species interacts with the other members of the ecosystem in an interdependent web of homeostasis. Their loss is felt as ripple effects throughout the ecosystem. Some species are more crucial in the ecosystem than others. Honeybees are a prime example of this because of their work as pollinators. Another example, Wolves, were re-introduced into Yellowstone National Park in the late 90s. Since then, the entire ecosystem, and even the landscape of the park have begun to change, as you can see in this video:
As wildlife biologist Michael Hutchins describes it:
As we know from basic ecology, organisms in functioning ecosystems are interdependent and linked together in complex webs. The loss of one species can therefore result in a cascade of extinctions. Well known biologists Paul and Anne Ehrlich once liked this to taking the bolts out of a flying aircraft one at a time. It may hold together for a while, but eventually, a wing will fall off and the entire plane will crash (Ehrlich, P. and Ehrlich, A. 1981. Extinction: The Causes and Consequences of the Disappearance of Species. New York: Random House). This is especially true for so-called keystone species that are at the center of these complex relationships. To the extent that climate change results in species extinctions—either directly or indirectly—we are likely to see such extinction cascades occur, and this could result in a significant loss of biodiversity.
If I may offer up my own analogy: it is like removing pieces of a Jenga tower. Each species is a piece in a giant game of Jenga. We keep removing pieces, and eventually the whole thing collapses.
Beyond individual species decline, whole habitats are having major problems. Around 85% of global fish stocks are over-exploited, depleted, fully exploited or in recovery from exploitation. There are huge dead zones opening up in the coasts of the world’s oceans due to nitrogen run-off from rivers.
Dead zones where fish and most marine life can no longer survive are spreading across the continental shelves of the world’s oceans at an alarming rate as oxygen vanishes from coastal waters, scientists reported Thursday.
The scientists place the problem on runoff of chemical fertilizers in rivers and fallout from burning fossil fuels, and they estimate there are now more than 400 dead zones along 95,000 square miles of the seas – an area more than half the size of California.
The number of those areas has nearly doubled every decade since the 1960s, said Robert J. Diaz, a biological oceanographer at the Virginia Institute of Marine Science. (http://www.sfgate.com/green/article/Scientists-alarmed-by-ocean-dead-zone-growth-3200041.php)
Last March, the EPA released a study saying more than half, 55%, of all the rivers and streams in the United States are in poor condition for aquatic life. Let me repeat that for emphasis. Half of all rivers in the US are in poor condition for aquatic life. The study also declared “Over 13,000 miles of rivers are found to have mercury in fish tissue at levels that exceed thresholds protective of human health.”
Half of the topsoil on the planet has been lost in the last 150 years. Soil is not just dirt, but a living ecosystem of organisms, microscopic and otherwise, that live in the humus of the surface of the Earth. Earthworms, nematodes, protozoa, fungi, bacteria, and different arthropods, along with other flora and fauna, exist within this depleting habitat.
All of these worldwide threats to ecosystems have led some scientists to dub this the Anthropocene Extinction, as the name of the sixth great mass extinction event of the world, which we are in the midst of, because it is being caused or perpetuated by human influence. The present rate of extinction may be up to 140,000 species per year. Polling done by the American Museum of Natural History “finds that seven in 10 biologists believe that mass extinction poses a colossal threat to human existence, a more serious environmental problem than even its contributor, global warming; and that the dangers of mass extinction are woefully underestimated by almost everyone outside science.”
We should all be sitting up to pay attention and worry. Habitat loss, deforestation, climate change, desertification, pollution, and other deleterious human activities, are threatening a biodiversity crisis that compromises the complex ecosystems all life, including humans, depend on.