Geologic Time Goes Over Billions of Years
A Planet With Brains? Peril & Potential of Self-Aware Geological Change
From an Article by David Grinspoon, 13.7 NPR Blog, December 18, 2016
The universe is 13.7 billion years old. Now we have something new! Recent years have seen a vigorous debate over whether or not we have entered a new epoch of geologic time, the “Anthropocene,” characterized by humanity as a new geologic force.
Much of this has centered over when this age began. Three candidates for this include: an “Early Anthropocene” many thousand years ago when humans first started large-scale modification of land and climate; the beginning of the industrial revolution with its CO2 emissions; and the nuclear test horizon. Choosing a single moment of origin may be less important than the realization that we are now in it. However, the debate has been fruitful, as all these candidates mark interesting steps in our journey from being just another primate to becoming a dominant geological force.
As a planetary astrobiologist, I am focused on the major transitions in planetary evolution and the evolving relationship between planets and life. I want to frame our current time as a stage in the cosmic life of our planet. What I wonder most about the Anthropocene is not when did it start — but when, and how, will it end? Will it end? Or is it possible that our own growing awareness of our role on Earth can itself play a pivotal role in shaping the outcome toward one that we would desire?
Although it has been proposed as a new epoch, we may in fact be experiencing something much more unusual. Picture the “geologic time scale” you’ve seen where the various phases of Earth’s history are represented by a sequence of different layers corresponding to the rocks from different geological ages, with the most recent periods drawn at the top. New epochs are actually rather common in Earth’s history. They typically last for millions of years. They are marked by the relatively thin layers in geological time. Their boundaries are often characterized by episodes of global change and extinction events. Much more rare and consequential are the boundaries, separating the longest phases, the billion-year-scale chunks of time called eons.
Geologists separate our planet’s long history into only four eons. These represent fundamental branching points which each left the world permanently changed. I suspect we may now be at another of these pivotal moments, and our planet may be at the beginning of its fifth eon, which I propose we call the “Sapiezoic” (a hopeful, aspirational term meaning “age of wisdom”). Because what we are observing are the effects of not only a new geologic force, but a radically new type of geologic change. Never before has a geological force become aware of its own influence.
The first eon is named the Hadean because it was pure hell, with leftover debris from planet formation crashing down from space, erratically smashing, churning and heating Earth’s surface, making red-hot atmospheres first of vaporized rock and then of boiling steam. Eventually, the cosmic pounding subsided and the steam turned to rain, which filled the first oceans.
The transition to Earth’s second Eon, the Archean, came around 4 billion years ago and corresponds roughly to the coming of stable habitable conditions and the origin of life. Since then, biology has been a major agent of geologic change.
Earth’s third eon, the Proterozoic, beginning 2.5 billion years ago, corresponds roughly to the Great Oxygenation Event when, chemically, life took over the planet. In discovering solar energy, photosynthetic bacteria began to flood the atmosphere with oxygen, a poisonous gas that caused mass extinction, but also created the chemical conditions for animal respiration and the protective ozone layer that allowed life to leave the oceans and colonize the land.
Then, 540 million years ago, came the Cambrian Explosion — the sudden appearance of complex, multicellular animal and plant life forms. This enabled, among many other things, the evolution of intricate nervous systems, elaborate behavior and learning. This explosion of biological innovation is recognized as the beginning of the fourth and final (so far) eon of Earth’s history — the Phanerozoic Eon, which continues to this day.
Now, humans have become a dominant force of planetary change and, thus, we may have entered an eon of post-biological evolution in which cognitive systems have gained a powerful influence on the planet. The beginning of a time when self-aware cognitive processes become a key part of the way the planet functions is potentially as significant as the origin of life and the pivotal changes marking the two other eon boundaries in Earth’s history.
Yet to become a new eon, such a transition would require an additional quality: great longevity. Can this new force possibly persist for millions or billions of years? This is closely related to the subject of SETI (the Search for Extraterrestrial Intelligence), whose theorists have long recognized that the number of technological civilizations in the universe must be proportional to their average longevity. The literature of this field is filled with discussion of the potential longevity of human-like civilizations elsewhere in the galaxy. What exactly do we mean by “human-like?” That is a wonderful question that connects questions of our essential nature, our exceptionalism compared to the rest of life, and our role on the planet. Can a civilization become integrated into the cyclic functioning of its planet in a sustainable way? This implies a different mode of interaction with the planet than is currently being exhibited by “intelligent” life.
From a systems perspective, the early stages of this transition are highly unstable because global influence precedes global control. Such a system is characterized by unstable positive feedbacks which threaten catastrophe. Hence the dangers of our current “Anthropocene dilemma”: We have global influence without global self-control. However, global technological influence clearly contains both peril and promise. Conscious awareness and control can also be sources of stabilizing negative feedback. This merely requires recognizing a problem and acting to fix it.
We’ve done this with our, so far, successful efforts to repair the ozone layer. There are pathways by which this stabilizing cognitive phenomenon could become a very long-lived and even permanent part of the Earth system. This would require that we reach a stage where we have a deep understanding of nature and an ability to forestall natural disasters, as well as the deep self-understanding necessary to forestall self-imposed disasters. In other words, it will require both technical and spiritual progress.
How does this affect the way we view our future? It reframes our task. And it puts our immediate challenges over the next century, stabilizing population and devising an energy system that can provide for the needs of this population without wrecking the natural systems upon which we depend, against the backdrop of a much longer-term challenge. Once we get over the relatively short-term, century-scale threat of destabilizing fossil-fuel induced climate change, we need to learn how to become a long-term stabilizing factor on the planet. This will include: over the next several hundred to thousand years, asteroid and comet defense; over the next several tens of thousands of years, learning how to prevent ice ages and natural episodes of dangerous global warming; over several billions of years, compensating for the warming sun and preventing the inevitable runaway global warming that will otherwise result from solar evolution.
Our current struggles and anxieties about the future must be faced with an awareness of the very long view. We need to have a vision of the world we want to create so that we can see ourselves as collaborators with future generations in the project of shaping it.
The story of our species is one of overcoming existential risk through new forms of cooperation and innovation. Our current dilemmas require these same skills applied on new temporal and spatial scales. Although right now we are initiating a mass extinction, in the long run, by preventing future extinctions and prolonging the life of the biosphere, we could be the best thing that ever happened to planet Earth.
>>> David Grinspoon is a senior scientist at the Planetary Science Institute. His latest book, Earth in Human Hands: Shaping Our Planet’s Future, was published in December 2016.
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{ 2 comments… read them below or add one }
This is a very important idea.
Most of us drift along in the day-to-day mode, not even aware of our short-term history. How many can name our great grandparents?
Nor do we have any idea of our future prospects, how easy it is to discontinue our means of life support, our retirement, health care, friends, job.
Hardly anyone understands our fragile dependence on food, security, and happiness provided by others.
There are various so-called evils in the world, and we are accustomed to ignoring them.
Tom Bond, Lewis County, WV
We’ll Never See These Animals Again
By Laura Smith, Mother Jones Magazine, December 31, 2016
If 2016 was a rough year for the animal kingdom, 2017 could be worse. Most scientists agree that we are experiencing a sixth mass extinction, but unlike the previous five that extended over hundreds of millions of years and occurred because of cataclysmic natural disasters, humans are responsible for this one.
Climate change, agricultural expansion, wildlife crime, pollution, and disease have created a shocking acceleration in the disappearance of species. The World Wildlife Fund recently predicted that more than two-thirds of the vertebrate population—mammals, birds, fish, amphibians, and reptiles—would be lost over the next three years if extinctions continue at the current rate. A 2015 study that appeared in the journal Science Advances suggests that the rate of vertebrate extinction has increased nearly 100 times.
Paul Ehrlich, a professor of population studies at Stanford University and a co-author of the study, notes half the life forms that people know about are already extinct. Another study, published in the journal Current Biology, observes that some species are likely becoming extinct before scientists have a chance to discover and classify them. Researchers looking at Brazil’s bird populations found some already so threatened when they were discovered, they went extinct almost immediately. “That we have these examples,” the authors write, “may be by good luck: we will surely have missed many others.”
Scientists have cautioned against making sweeping overall estimates, rather than talking about risks for specific populations. As Duke University professor of Conservation Ecology, Stuart Pimm, observed, even though animal populations are “declining precipitously,” pinpointing exactly how many animals will be gone and the timeframe for their extinction doesn’t capture the complexity of the problem. “It’s bird populations in Europe, it’s fish in the Pacific,” Pimm says. “You can’t add those together and come up with a number that makes any sense.”
The International Union for Conservation of Nature (IUCN) has tried to show the scope of the problem in its Red List, a comprehensive roster of threatened species. Here are some of the highlights, including three species that went extinct last year and others to watch out for in 2017:
The Bramble Car melomys: This small Australian rodent that resembled an ordinary mouse was confirmed as extinct in 2016. It is the first known mammal to go extinct as a result of human-caused climate change. Its habitat on an island in the Great Barrier reef was assaulted by the rise of sea levels, coastal erosion, and flooding—all driven by climate change.
Rabbs’ fringe-limbed tree frog: In 2016, the appropriately named Toughie died in the Atlanta Botanical Garden. He was at least twelve years old, though his exact age is unknown. Toughie and another Rabb’s fringe-limbed tree frog were collected from Panama in 2005 for research on chytrid fungus, a deadly fungus that has been ravaging amphibian populations in the region. Amphibians, like Toughie, have the highest rate of endangerment, with a third of known species being at risk of extinction. Toughie became the face of the amphibian extinction crisis as visitors to his enclosure knew they were looking at the last of his kind.
Toughie became the face of the amphibian extinction crisis as visitors to his enclosure knew they were looking at the last of his kind.
Dolphins and porpoises: There has been a lot of alarming news about the ocean recently: A UN report found that ocean acidification is up around 26 percent, and more than half of the sharks and rays in the Mediterranean are at risk of extinction. But, in 2016, with a population of only three, the Irrawaddy dolphin in Laos was declared “functionally extinct.” The announcement came after a World Wildlife Fund survey of Cambodia and Laos determined there were not enough mating pairs for the species to survive. Resembling Flipper—except with a bulbous face instead of a bottle nose—this sea faring mammal’s extinction is blamed on gill nets, a type of netting used by commercial fishermen that trap fish by their gills. Dolphins are caught in the nets and drown.
Vaquita, or “Little cow” in Spanish, is the smallest species of porpoise, and the remaining few live in the Gulf of California. Vaquita are so rare that some people who live on the Gulf don’t believe they exist, according to a recent Vaquita documentary. In May, a Conservation Biology acoustics survey found that there are only 60 left. Now, some have dropped the estimate to fewer than 50. Like the Irrawaddy dolphin, they are victims of gill net fishing.
African Grey Parrot: In December 2016, the International Union of Concerned Naturalists revealed that 11 percent of newly discovered bird species were already threatened and changed the status of others, such as the African Grey Parrot, from “vulnerable” to “endangered.” Highly intelligent and capable of mimicking human speech, the African Grey Parrot’s population has shrunk by as much as 99 percent in some places because of habitat loss and trapping. Perhaps the most famous member of this species was Alex, the subject of intelligence studies at Harvard and Brandeis universities who, when he died in 2007, knew more than 100 English words.
Giraffes: Bad news for the planet’s tallest land creature was announced before the end of 2016: Giraffe populations are plunging in what scientists call a “silent extinction” due to poaching and habitat loss. (The extinction is “silent” because we had largely failed to notice their plummeting population.) Previously, the IUCN’s Red List had given them a “least concern” rating. News that their populations have dropped by as much as 40 percent since 1985 has caused their status to be changed to vulnerable.
Jaguars and most large cats: The protection of all big cats will be important in the coming years, as populations continue to plummet. The African lion population, for example, has dropped 90 percent. At the end of December, a study from the journal Proceedings of the National Academy of Sciences reported that the fastest land animal on earth, the cheetah, now only has a worldwide population of about 7,000. That’s down from its population of about 100,000 a century ago. The study attributed the drop to habitat loss: Cheetahs have lost 91 percent of their range.
Large cats are also endangered in our own backyard. “El Jefe,” who was named by Arizona school children, is the only known wild jaguar in the United States, but it is an elusive animal whose exact whereabouts are often unknown. In February, the Center for Biological Diversity released a video of the enormous cat slinking through the mountainside in the Santa Rita mountains outside of Tuscon. Randy Serraglio, a biologist at the Center for Biological Diversity who tracks El Jefe, suggests the animal has likely migrated to Mexico in search of mates. Once there, it faces other dangers from ranchers, who kill jaguars for sport or out of concern for their livestock, Mexican newspapers reported. Back in the US, a Canadian mining company might threaten El Jefe’s habitat by developing a massive open pit copper mine through its territory in Arizona. On top of all that, should Donald Trump actually make good on his proposed border wall, jaguar migratory patterns would be disrupted.
Rhinos: These massive mammals have long been hunted for their horns, which are erroneously believed to have healing properties. The western black rhino is already extinct and there are only three northern white rhino left. There is still a small population of Javan Rhinos in Indonesia, but two other subspecies, one in Vietnam, have also gone extinct. In 2016, numbers showed that the previous year was the worst year ever for rhino poaching. Given the trends, scientists predict that the entire wild rhino population will go extinct between 2021 and 2031. Many of the horns already on the market are fake, and some companies are trying to deal with the crisis by flooding the rhino horn market with 3-D prints of rhino horns, under the dubious assumption that this will make poaching less lucrative. However, some conservationists argue that it could actually make things worse by removing the stigma about using the horn and making it harder for law enforcement officers to track poachers.
Yellow-faced honeybee: Seven species of Hawaii’s yellow-faced bees made it onto the endangered species list last year, but more than a quarter of the bee population in the US is also in trouble. This has potentially devastating consequences for the planet’s food supply: Bees are responsible for pollinating more than a third of the world’s food.
The African elephant: The Endangered Species Coalition reports that the population of the largest land animal in the world—once 10 million strong—has fallen to about 400,000. The Great Elephant Census, a pan-African census that collects data using small planes, reports that the Savannah elephants have lost nearly a third of their population in the last seven years. The population drop is attributed to ivory poaching and loss of habitat. If poaching continues at its current rate, there will be no African elephants in 20 years.
Source: http://www.motherjones.com/environment/2016/12/animals-extinct-last-year-what-to-watch-2017