‘We Should Be Worried’: Study Confirms Fear That Intense Ocean Acidification Portends Ecological Collapse

“We have been warned.”

A new study regarding fossil records reveals that ocean acidification could cause mass extinction. (Photo: Rodfather/Flickr/cc)

The acidification of the Earth’s oceans, which climate scientists warn is a dangerous effect of continued carbon emissions, was behind a mass extinction event 66 million years ago, according to a new study.

Small-shelled marine organisms survived the meteorite that struck the Earth and wiped out the dinosaurs, according to researchers at the GFZ geosciences research center in Potsdam, Germany, but the subsequent sharp drop in pH levels in the ocean caused the marine life to go extinct.

“We show ocean acidification can precipitate ecological collapse,” Michael Henehan, who led the study, told The Guardian.

Researchers examined shell fossils in sediment dating back to the time period just after the meteorite struck the planet, which showed that the oceans’ pH dropped by about 0.25 units in the 100 to 1,000 years after the strike.

“In the boundary clay, we managed to capture them just limping on past the asteroid impact,” Henehan said.

But, the newspaper reported, “It was the knock-on effects of acidification and other stresses, such as the ‘nuclear winter’ that followed the impact, that finally drove these foraminifera to extinction.”

“We have been warned,” climate campaigner Ed Matthew tweeted with a link to the research, which was published in the Proceedings of the National Academy of Sciences.

Today, climate scientists warn that the continued burning of oil, gas, and coal is causing ocean acidification that, left unchecked, could cause a pH drop of 0.4 units.

If policymakers are able to help limit the warming of the globe to two degrees Celsius by ordering that fossil fuels be left in the ground and shifting to a renewable energy economy, the ocean’s pH level could drop just 0.15 units.

“If 0.25 was enough to precipitate a mass extinction, we should be worried,” Henahan told The Guardian.

As Common Dreams reported in July, MIT researchers also recently turned their attention to ocean acidification as well. The researchers released data showing that today’s carbon levels could be fast approaching a tipping point threshold that could trigger extreme ocean acidification similar to the kind that contributed to the Permian–Triassic mass extinction, which occurred about 250 million years ago.

What we lose when animals go extinct

Animals are disappearing at hundreds of times the normal rate, primarily because of shrinking habitats. Their biggest threat: humans.

No trace of the wild South China tiger, Panthera tigris amoyensis (critically endangered, possibly extinct in the wild), has been seen for more than a decade. Zoos hold fewer than 200 in… Read More

This story appears in the October 2019 issue of National Geographic magazine.


Most of the animals shown here are among the more than 28,000 species of animals and plants that the International Union for Conservation of Nature says are threatened with extinction. That number actually understates the risk. Since 1964, when the IUCN established a “red list” of threatened species and began compiling data gathered worldwide, the list has become the preeminent global database of endangered life and an essential tool for conservation policy. Yet the IUCN has been able to assess only about 106,000 species of the more than 1.5 million species of animals and more than 300,000 plants that scientists have described and named—which they estimate is less than a quarter of what’s really out there. A recent intergovernmental report on the biodiversity crisis estimated that extinction threatens up to a million animal and plant species, known and unknown. The IUCN hopes to raise the number of species assessments to 160,000 by 2020. Next up on its agenda: a “green list” of conservation successes. It will be much shorter than the red one.

The large yellow-footed tortoise, Chelonoidis denticulata (vulnerable), from South America and the Caribbean, is hunted for its meat, which is considered a delicacy. It also is captured and traded as a pet.KANSAS CITY ZOO, MISSOURI


Habitat loss—driven primarily by human expansion as we develop land for housing, agriculture, and commerce—is the biggest threat facing most animal species, followed by hunting and fishing. Even when habitat is not lost entirely, it may be changed so much that animals cannot adapt. Fences fragment a grassland or logging cuts through a forest, breaking up migration corridors; pollution renders a river toxic; pesticides kill widely and indiscriminately. To those local threats one must increasingly add global ones: Trade, which spreads disease and invasive species from place to place, and climate change, which eventually will affect every species on Earth—starting with the animals that live on cool mountaintops or depend on polar ice. All of these threats lead, directly or indirectly, back to humans and our expanding footprint. Most species face multiple threats. Some can adapt to us; others will vanish.

Left: Humphead wrasse, Cheilinus undulatus (endangered)
Right: Arctic fox, Vulpes lagopus (least concern)
Lesser flamingo, Phoeniconaias minor (near threatened)CLEVELAND METROPARKS ZOO

If we lived in an ordinary time—time here being understood in the long, unhurried sense of a geologic epoch—it would be nearly impossible to watch a species vanish. Such an event would occur too infrequently for a person to witness. In the case of mammals, the best-studied group of animals, the fossil record indicates that the “background” rate of extinction, the one that prevailed before humans entered the picture, is so low that over the course of a millennium, a single species should disappear.

But of course we don’t live in an ordinary time. Everywhere we look, species are winking out. Just in the past decade, two mammal species have gone extinct: a bat known as the Christmas Island pipistrelle and a rat, the Bramble Cay melomys.

The International Union for Conservation of Nature lists more than 200 mammal species and subspecies as critically endangered. In some cases, like the Sumatran rhino or the vaquita—a porpoise native to the Gulf of California—there are fewer than a hundred individuals left. In others, like the baiji (also known as the Yangtze River dolphin), the species, though not yet officially declared extinct, has probably died out.

Bachman’s warbler, Vermivora bachmanii (critically endangered, possibly extinct)
One of the United States’ smallest native warblers, it may already be extinct because of severe habitat loss from development in the southeastern U.S. and its Cuban wintering grounds. The last time a live sighting was reported was in 1988.TALL TIMBERS RESEARCH STATION AND LAND CONSERVANCY, FLORIDA

And unfortunately, what goes for mammals goes for just about every other animal group: reptiles, amphibians, fish, even insects. Extinction rates today are hundreds—perhaps thousands—of times higher than the background rate. They’re so high that scientists say we’re on the brink of a mass extinction.

The last mass extinction, which did in the dinosaurs some 66 million years ago, followed an asteroid impact. Today the cause of extinction seems more diffuse. It’s logging and poaching and introduced pathogens and climate change and overfishing and ocean acidification.

But trace all these back and you find yourself face-to-face with the same culprit. The great naturalist E.O. Wilson has noted that humans are the “first species in the history of life to become a geophysical force.” Many scientists argue that we have entered a new geologic epoch—the Anthropocene, or age of man. This time around, in other words, the asteroid is us.

Gray woolly monkey, Lagothrix cana (endangered)
This young, malnourished woolly monkey from Brazil was raised as a pet. When she was captured, her mother likely was killed. Environmental police rescued her, and she’s been treated, but she’ll need to live in captivity the rest of her life.CETAS-IBAMA, BRAZIL

What’s lost when an animal goes extinct?

One way to think of a species, be it of ape or of ant, is as an answer to a puzzle: how to live on planet Earth. A species’ genome is a sort of manual; when the species perishes, that manual is lost. We are, in this sense, plundering a library—the library of life. Instead of the Anthropocene, Wilson has dubbed the era we are entering the Eremozoic—the age of loneliness.

This article is adapted from Joel Sartore’s new book, Vanishing, published by National Geographic Books.

Joel Sartore has been photographing animals for his Photo Ark project for 13 years. In an ever growing number of cases, animals housed in zoos or special breeding facilities are among the last remaining members of their species. In some instances, they are the only members.

Toughie, a Rabbs’ fringe-limbed tree frog from central Panama, lived at the Atlanta Botanical Garden. He became the last known of his kind when a fungal disease swept through his native habitat and a captive-breeding program failed. Toughie died in 2016, and it’s likely the Rabbs’ fringe-limbed tree frog is now extinct.

Romeo, a Sehuencas water frog that lives at the natural history museum in Cochabamba, Bolivia, was likewise believed to be a sole survivor. Scientists created an online dating profile for him. It linked to a donation page, and the $25,000 raised helped fund expeditions in the eastern Andes, where the species was once abundant.

Amazingly, the search has revealed five more Sehuencas water frogs, two males and three females. All were taken to Cochabamba; the one female mature enough to breed with Romeo was named Juliet. Whether she will prove a worthy mate and perpetuate the species, no one knows.

Was the Rabbs’ fringe-limbed tree frog beautiful? Not in the flashy way of, say, the Spix’s macaw (which is believed to be extinct in the wild) or the Gee’s golden langur (which is endangered). But with its expressive brown eyes and gangly limbs, it had its own kind of charm.

Niho tree snail, Partula nodosa (extinct in the wild)ST. LOUIS ZOO

Sartore treats all creatures—great and small, handsome and homely—with reverence. His photos capture what’s singular and, I’d also like to say, soulful about every living thing. One of my favorite images of Joel’s is of a Partula nodosa, or niho tree snail, laying down a trail of slime. There used to be dozens of Partula species in the South Pacific, occupying different islands and different ecological niches. Much like Darwin’s finches, they are the darlings of evolutionary biologists—living, slime-producing illustrations of the power of natural selection. The introduction of carnivorous snails from Florida drove nearly a third of the Partula species extinct; several survive solely thanks to captive-breeding programs.

Precisely because extinction takes place so frequently now, it’s possible to become inured to it. This desensitizing is what makes Sartore’s images so crucial: They show us just how remarkable each species is that’s being lost.

We live in an extraordinary time. Perhaps by recognizing this, we can begin to imagine creating a different one—one that preserves, as much as is still possible, the wonderful diversity of life.


Since the 1980s, a fungal disease called chytridiomycosis, likely spread through direct contact and by infected water, has ravaged global amphibian populations. More than 500 species have been affected; 90 of these may be extinct. The fungus disrupts transmission of electrolytes through the skin of a frog or toad, ultimately stopping its heart.


Kagu, Rhynochetos jubatus (endangered)
Like many island species, the nearly flightless kagu, native to the French Pacific territory of New Caledonia, was seriously affected by the arrival in the late 1700s of European settlers and their animals. Roughly chicken size, the kagu continues to fall prey to non-native pigs, cats, and dogs. The birds nest on the ground, and rats eat their eggs. Recent population estimates suggest fewer than a thousand kagu survive. Scientists nevertheless have some hope for the future: Decades of successful captive breeding have resulted in the reintroduction of the birds to the wild, and predator control has allowed some populations to rebound.HOUSTON ZOO


Mhorr gazelle, Nanger dama mhorr (critically endangered)
This subspecies of the dama gazelle was once widespread across the western Sahara. Now there are fewer than 300 damas combined in Mali, Chad, and Niger. Their range is broken up by grazing lands for livestock, and they’re at risk from hunting. Reintroduction of captive-bred animals has had mixed success.BUDAPEST ZOO


Butterflies can fly long distances and feed on many types of flowers, but caterpillars are locavores, eating plants they hatch on or near. As those plants are lost to development or farming, butterflies disappear. The ones here aren’t listed by the IUCN—which has evaluated only 8,100 insect species—but are considered at risk by other authorities.


Asian elephant, Elephas maximus (endangered)
Early in the 20th century, perhaps 100,000 elephants roamed across Asia. Since then, their population likely has been cut in half. They’re killed not just for their ivory tusks but also for their meat and hides—and sometimes in retaliation for the damage they do to crops.LOS ANGELES ZOO


For tree-dwelling lemurs, there’s no life without the forest—or Madagascar, their only home. Yet the island nation has lost 80 percent of its trees to development, charcoal production, and slash-and-burn agriculture. Lemurs are squeezed into limited protected areas; 38 species are critically endangered. Fuel-efficient stoves are being introduced to encourage people to reduce wood use and protect forest habitat.

Diademed sifaka, Propithecus diadema (critically endangered)
Females may only be fertile one day a year, limiting this lemur’s ability to rebuild fragmented populations.LEMUR ISLAND, MADAGASCAR
Left: Aye-aye, Daubentonia madagascariensis (endangered)
Though rare, this lemur—the world’s largest nocturnal primate, at around six pounds—is still found across the island. But local lore holds that aye-ayes are bad luck, and they’re often killed… Read More

‘Bird emergency’: Climate change threatening two-thirds of species in U.S. with extinction, report says


North America has lost nearly three billion birds since 1970, a new study says, which also found significant population declines among hundreds of bird species, including those once considered plentiful. USA TODAY

About two-thirds of America’s birds will be threatened with extinction if global warming tops 5.4 degrees by 2100, according to a report released Thursday from the National Audubon Society, a bird-focused conservation group.

“A lot of people paid attention to last month’s report that North America has lost nearly a third of its birds,” said David Yarnold, CEO and president of Audubon. “This new data pivots forward and imagines an even more frightening future. It’s a bird emergency.”

About 389 out of 604 species are at risk of extinction from climate change. A few of the imperiled species include state birds such as Minnesota’s common loon, New Jersey’s goldfinch and California’s quail.

To prepare the report – “Survival by Degrees: Bird Species on the Brink” – Audubon scientists studied 604 North American bird species using 140 million bird records, including observational data from bird lovers and field biologists across the U.S., Canada and Mexico.

In addition to warming temperatures, the scientists also looked at climate-related impacts on birds across the lower 48 states, including sea-level rise, Great Lakes’ water-level changes, urbanization, cropland expansion, droughts, extreme spring heat, fire weather and heavy rain.

“Birds are important indicator species because if an ecosystem is broken for birds, it is or soon will be for people, too,” said Brooke Bateman, Audubon’s senior climate scientist.

Related: These species went extinct in 2018. More may be doomed to follow in 2019

In 2014, Audubon published its first “Birds and Climate Change Report.” The study showed that more than half of the bird species in North America could lose at least half of their current ranges by 2080 because of rising temperatures. Audubon’s new findings reflect an expanded and more precise data set, and indicate the dire situation for birds and the places they need will continue.

On a conference call with reporters Thursday, Yarnold said that “birds localize and personalize climate change.” Each and every North American bird species will experience some level of impact from global warming, he said.

The report offered some hope, noting that if the greenhouse gas emissions that bring about climate change are reduced, then we can boost the odds of survival for many bird species.

“By stabilizing carbon emissions and holding warming to 2.7 degrees above pre-industrial levels, 76% of vulnerable species will be better off, and nearly 150 species would no longer be vulnerable to extinction from climate change,” the report said.

“We already know what we need to do to reduce global warming, and we already have a lot of the tools we need to take those steps,” said Renee Stone, vice president of climate at Audubon.

“Now, what we need are more people committed to making sure those solutions are put into practice,” she said.

“Our elected officials at every level of government must hear from their constituents that this is a priority,” she said. “Audubon is committed to protecting the places birds need now and in the future and taking action to address the root causes of climate change.”

This work is the most comprehensive model-based assessment of climate change vulnerability of birds in North America to date, according to Audubon.

“Our findings in this report are the fifth alarm in a five-alarm fire,” said David O’Neill, Audubon’s chief conservation officer, in the study.

For more information, check out Audubon’s ZIP code-based tool, the Birds and Climate Visualizer, which helps users understand the impacts to birds where they live.

Dinosaurs’ Painful Deaths After Asteroid Impact Described By Expert

Ahistory expert provided a detailed account of the horrible deaths the dinosaurs went through seconds after Earth was hit by a massive asteroid 66 million years ago. Many of the large animals were boiled alive, crushed to death and pelted by molten rocks during the catastrophic event.

Near the end of the Cretaceous Period, an asteroid with a diameter of about 50 miles crashed in a region now known as the Yucatan Peninsula in Mexico. The massive impact event created a 93-mile-wide crater with a depth of 12 miles.

The initial explosion from the asteroid caused a series of environmental effects that immediately killed off a large number of dinosaurs around the impact zone. In his recent article for the Daily Mail, journalist and history author Jonathan Mayo gave an in-depth look at the gruesome deaths some of the dinosaurs went through following the massive asteroid impact.

According to Mayo, just a few moments after impact, the massive explosion generated by the asteroid caused the temperature in the surrounding area to rise rapidly. This caused the water in the skin of the animals near the impact zone to boil and burst out as steam. Those that managed to avoid boiling to death were immediately incinerated by the intense heatwave from the blast.

After the asteroid hit the ground, it sent thousands of molten rock and debris known as tektites flying into the air. Many of these pelted the ground, puncturing the skin of both flying and land-based dinosaurs.

“Molten rock flung high into the air is cooling as it falls, creating small glass ‘bullets’ known as tektites,” Mayo stated in his article. “These puncture wings of the quetzalcoatluses, and one by one they start falling from the sky.”

“In Hell Creek, Montana, red-hot tektites thump into the dying Tyrannosaurus Rexes, burning holes in their skin,” he added.

In addition to the extreme heat and tektites, the asteroid impact also generated violent earthquakes in different areas. The falling rocks and trees caused by the powerful seismic activity crush the small dinosaurs as they were trying to flee.

These are only some of the events that contributed to the massive die-offs 66 million years ago. As scientific reports have shown, the impact event triggered extreme climate changes that led to a nuclear winter all over the planet, which wiped out over 70 percent of all life on Earth.

Asteroid ImpactsA new report indicates that a total of 26 nuclear-level asteroid impacts have hit Earth since 2000. 

‘It doesn’t feel justifiable’: The couples not having children because of climate change

Morgan and Adam have always wanted children but fears over climate change are making them reconsider.

The committed pair, aged 36 and 35, are part of a growing trend for young couples to abandon plans for a family because of the climate crisis.

Millions of people around the world rallied for climate action over the past two days, including 300,000 in Australia on Friday, ahead of a United Nations climate action summit on Monday.

Morgan and Adam have always wanted children but are worried about climate change.
Morgan and Adam have always wanted children but are worried about climate change.CREDIT:STEVEN SIEWERT

“I feel so sad, it’s such a hard thing to let go of,” says Morgan, who works in logistics. “My conscience says, ‘I can’t give this child what I’ve enjoyed, I can’t give them the certainty of a future where they can be all that they can be … or have the things they should have, like breathable air and drinkable water’.”

Morgan is feeling “pretty damn certain” a baby is off the cards, even though she fears she might regret it. She has at least two close friends in their early 30s, with good partners, who have made the same decision.

Her partner Adam, who works in web development, agrees. “I have a lot of love to give and would love to raise a child … but it doesn’t feel justifiable. The world is heading blindfolded towards catastrophe.”

Prince Harry made headlines when he revealed in an interview in British Vogue, in the September issue guest-edited by his wife Meghan, that the couple would have two children “maximum” for the sake of the planet.

The idea of limiting family size to two children to represent net zero population growth has been around for decades. But is no children the new two children?

Dr Bronwyn Harman, a lecturer at Edith Cowan University in Perth who studies people without children, says it is a progression of the same theme. She says some people are avoiding parenthood because they are worried for their unborn children, while others are motivated not to make things worse.

“They’re saying things like ‘we don’t want to add children into the mix and put more strain on the planet’,” Harman says. “It’s started coming up [in my research] in the past six months but it’s not very common.”

The phenomenon is growing. The Age and Sun-Herald have spoken to 20 and 30-somethings all over Australia wrestling with the dilemma. Most asked to use first names only to avoid online harassment.

“I’m terrified that in another 50 years, if my hypothetical child was all grown up, what would our world look like?” says Jessica Ivers, 29. The digital specialist and yoga teacher from Northcote in Melbourne says she is “100 per cent certain” about her choice.

In Mackay in Queensland,  community organiser Emma, 32, says she and her partner Mick, 33, were planning to start trying for a family next year but changed their minds after the federal election.

“After the LNP won – with no climate plan – we cried and agreed that the dream of a family wouldn’t be for us,” Emma says. “It’s a terrifying thought for us that the world will be uninhabitable in a few decades if we continue charging ahead with fossil fuels and approving coal mines like Adani.”

Melanie, 24, from Highgate Hill in Brisbane terminated an unplanned pregnancy last year and says the climate crisis was the “ultimate deciding factor”. She read scientific articles about the best and worst-case scenarios and decided she would never have children.

“It’s been a hard year coming to terms with the reality of the situation,” says Melanie. “I cannot justify bringing children into a world in the midst of a mass extinction event and facing total ecological collapse. “

Shalini and David would prefer to foster or adopt so they're not adding to the population.
Shalini and David would prefer to foster or adopt so they’re not adding to the population.CREDIT:LOUISE KENNERLEY

Shalini, 33, and David, 35, from Summer Hill in Sydney have decided not to have biological children but would like to adopt or foster in the future.

“It makes more sense for us to look after a child that is here and needs someone rather than make more children,” says David, a 3D animation artist.

Shalini, a public servant, says climate change is a big reason, along with her focus on career.

“I don’t eat meat and I’m really conscious about consuming goods and services that that are more sustainably produced and in the same vein, I don’t want to produce more people,” Shalini says. She finds it hard to discuss with friends because she doesn’t want them to feel judged.

Maddie, 32, from the lower north shore, sought counselling to deal with her grief and anxiety over climate change and her dilemma over having children.

“My psychologist is having more and more couples coming to her about this,” she says. “The first thing she said to me was, ‘this is not a manifestation of normal anxiety, this is a real threat and real grief that you’re carrying’.”

Maddie would love children but feels an obligation to fight for her newborn niece and friends’ children instead.

Australian Bureau of Statistics figures suggest one in four women aged 15 to 35 will never have children. Harman says roughly two-thirds of those women make an active choice to be “child-free” while one-third are “childless” because of circumstances, including fears over the state of the world.

A global trend

In Britain musician and activist Blythe Pepino, 33, kicked off the “BirthStrike” – a movement of people pledging not to have children “due to the severity of the ecological crisis and the current inaction of governing forces in the face of this existential threat”.

In February, US Congresswoman Alexandria Ocasio-Cortez commented on the grim scientific outlook and political inaction: “It does lead young people to have a legitimate question: is it OK still to have children?”

American singer and actress Miley Cyrus, 26, told Elle magazine’s August 2019 US issue that Millennials didn’t want to reproduce because they knew the Earth could not handle it.

“We’re getting handed a piece-of-shit planet, and I refuse to hand that down to my child,” Cyrus says. “Until I feel like my kid would live on an Earth with fish in the water, I’m not bringing in another person to deal with that.”

Yet even at the coalface of climate change research, some see this as extreme. Earlier this month, Petteri Taalas, secretary-general of the World Meteorological Organisation (parent body of the Intergovernmental Panel on Climate Change), weighed into the debate.

“The latest idea is that children are a negative thing,” Taalas told a Finnish magazine. “I am worried for young mothers, who are already under much pressure. This will only add to their burden.”

He warned facts could be hijacked to justify “extreme measures” in the name of climate action.

Taalas told The Sun-Herald  in a statement he supports strong climate action and a science-based approach offers hope.

“We must not be driven to despair, given that reasonable solutions are available to the international community, governments and civil society,” he says.

David Attenborough – Humans are plague on Earth

Humans are a plague on the Earth that need to be controlled by limiting population growth, according to Sir David Attenborough.

Humans are plague on Earth – Attenborough

Sir David said commentary from presenters like himself is becoming less necessary as camera work is able to tell a story Photo: PA

The television presenter said that humans are threatening their own existence and that of other species by using up the world’s resources.

He said the only way to save the planet from famine and species extinction is to limit human population growth.

“We are a plague on the Earth. It’s coming home to roost over the next 50 years or so. It’s not just climate change; it’s sheer space, places to grow food for this enormous horde. Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now,” he told the Radio Times.

Sir David, who is a patron of the Population Matters, has spoken out before about the “frightening explosion in human numbers” and the need for investment in sex education and other voluntary means of limiting population in developing countries.

“We keep putting on programmes about famine in Ethiopia; that’s what’s happening. Too many people there. They can’t support themselves — and it’s not an inhuman thing to say. It’s the case. Until humanity manages to sort itself out and get a coordinated view about the planet it’s going to get worse and worse.”

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Sir David, whose landmark series are repeated from Monday on BBC2, starting with Life on Earth, has also spoken out about the change in wildlife documentaries during his lifetime.

The 86-year-old said commentary from presenters like himself are becoming less necessary as camera work is able to tell a story.

“I’m not sure there’s any need for a new Attenborough,” he said. “The more you go on, the less you need people standing between you and the animal and the camera waving their arms about.

“It’s much cheaper to get someone in front of a camera describing animal behaviour than actually showing you [the behaviour]. That takes a much longer time. But the kind of carefully tailored programmes in which you really work at the commentary, you really match pictures to words, is a bit out of fashion now … regarded as old hat.”

18 signs we’re in the middle of a 6th mass extinction

dead fish
A skeleton of a fish lies forgotten on the dry bed of Lake Peñuelas outside Santiago, Chile. 
Eliseo Fernandez/Reuters

The phrase “mass extinction” typically conjures images of the asteroid crash that led to the twilight of the dinosaurs.

Upon impact, that 6-mile-wide space rock caused a tsunami in the Atlantic Ocean, along with earthquakes and landslides up and down what is now the Americas. A heat pulse baked the Earth, and the Tyrannosaurus rex and its compatriots died out, along with 75% of the planet’s species.

Although it may not be obvious, another devastating mass extinction event is taking place today — the sixth of its kind in Earth’s history. The trend is hitting global fauna on multiple fronts, as hotter oceans, deforestation, and climate change drive animal populations to drop in unprecedented numbers.

These alarming extinction trends are driven by one key factor: humans. According to a 2014 study, current extinction rates are 1,000 times higher than they would be if humans weren’t around. A summary of a United Nations report released last month put it another way: “Human actions threaten more species with global extinction now than ever before,” the authors wrote.

That report, which assessed the state of our planet’s biodiversity, found that up to 1 million plant and animals species face extinction, many within decades, due to human activity.

Read more: Insects are dying off at record rates — an ominous sign we’re in the middle of a 6th mass extinction

Other recent research has led to similar conclusions: A 2017 study found that animal species around the world are experiencing a “biological annihilation” and that our current “mass extinction episode has proceeded further than most assume.”

Here are 18 signs that the planet is in the midst of a sixth mass extinction, and why people are primarily to blame.

Earth appears to be undergoing a process of “biological annihilation.” Up to half of the total number of animal individuals that once shared the Earth with humans are already gone.

skeleton deer

Michael Kinnaman/Getty Images

2017 study looked at animal populations across the planet by examining 27,600 vertebrate species — about half of the overall total that we know exist. They found that more than 30% of them are in decline.

Some species are facing total collapse, while local populations of others are going extinct in specific areas. That’s still cause for alarm, since the study authors said these localized extinctions are a “prelude to species extinctions.”

More than 26,500 of the world’s species are threatened with extinction, and that number is expected to keep going up.

Amur Leopard
The Amur leopard is critically endangered. 
DigitalART/Wikimedia Commons

According to the International Union for Conservation of Nature Red List, more than 27% of all assessed species on the planet are threatened with extinction. Currently, 40% of the planet’s amphibians, 25% of its mammals, and 33% of its coral reefs are threatened.

The IUCN predicts that 99.9% of critically endangered species and 67% of endangered species will be lost within the next 100 years.

According to the UN report, the number of species threatened with extinction could be closer to 1 million.

snow leopard

Getty Images/Mark Kolbe

The UN report estimated that 40% of amphibian species, more than 33% of all marine mammals and reef-forming corals, and at least 10% of insect species are threatened. The authors also found that more than 500,000 land species already don’t have sufficient natural habitat left to ensure their long-term survival.

Insects are dying off at record rates. Roughly 40% of the world’s insect species are in decline, according to one study.


Hillary Kladke/Getty Images

A study published earlier this year found that the total mass of all insects on the planet is decreasing by 2.5% per year.

If that trend continues unabated, the Earth may not have any insects at all by 2119.

“In 10 years you will have a quarter less, in 50 years only half left, and in 100 years you will have none,” Francisco Sánchez-Bayo, a coauthor of the study, told The Guardian.

That’s a major problem because insects like bees, hoverflies, and other pollinators perform a crucial role in fruit, vegetable, and nut production. Plus, bugs are food sources for many bird, fish, and mammal species — some of which humans rely on for food.

Bee Bombus Ruderarius
The Red-shanked Carder Bee was once widespread in England, Wales, and parts of Scotland. But its population declined an estimated 42% between 1980 and 2013. 
Dave McDonnell/Getty

Another recent study published in the journal Nature Communications looked at 353 wild bee and hoverfly species in the UK, and found that one-third experienced declines between 1980 and 2013.

The study authors noted that the geographic ranges of bee and hoverfly species declined by 25% — that’s a net loss of about 11 species per square kilometer. The primary cause was a reduction in the pollinators’ habitats.

The recent UN report calculated that projected declines in the populations of wild bees and other pollinators could put up to $577 billion in annual crop production at risk.

Insects aren’t the only creatures taking a hit. In the past 50 years, more than 500 amphibian species have declined worldwide — and 90 have gone extinct — due to a deadly fungal disease that corrodes frog flesh.

atelopus frog
A Panamanian Golden Frog outside El Valle, Panama. Most Atelopus frogs experienced a 90% decline or complete extinction from the chytrid fungus. 
Brad Wilson/Getty

recent study in the journal Science described the spread of chytridiomycosis, or chytrid fungus, and how quickly it has wreaked havoc on frog, toad, and salamander species around the world.

Humans have enabled the fungal disease to spread further than it otherwise could have, in large part because of the global wildlife trade.

According to the study authors, amphibian deaths associated with chytrid fungus represent the greatest recorded loss of biodiversity attributable to any one disease.

Another study published in the journal Current Biology noted that amphibians overall — not just frogs — are among the most highly threatened groups of animals, with at least 2,000 species estimated to be in danger of extinction.

The loss of even one species could also cause an “extinction domino effect” to ripple through an ecosystem, causing the entire community to collapse.

Gorilla families have already been formed thanks to the database.


A 2018 study published in Scientific Reports predicted that scientists are likely underestimating how many species are vulnerable to extinction.

“Failing to take into account these co-extinctions therefore underestimates the rate and magnitude of the loss of entire species from events like climate change by up to 10 times,” study co-author Corey Bradshaw said in a press release.

The research suggested that the loss of one species can make more species disappear (a process known as co-extinction) by causing a sudden shift in a system. For example, a species of flower could not survive without the pollinator it relies on.

“Co-extinctions are often triggered well before the complete loss of an entire species,” the study authors wrote.

A 2015 study examined bird, reptile, amphibian, and mammal species, and concluded that the average rate of extinction over the last century is up to 100 times higher than normal.

A Monarch butterfly rests on the finger of a woman in the Amanalco de Becerra sanctuary, on the mountains near the extinct Nevado de Toluca volcano, in Mexico, Thursday, Feb. 14, 2019. The monarch butterfly population, like that of other insects, fluctuates widely depending on a variety of factors, but scientists say the recoveries after each big dip tend to be smaller, suggesting an overall declining trend. (AP Photo/ Marco Ugarte)
The monarch butterfly population, like that of other insects, fluctuates widely. But scientists say the recoveries after each big dip tend to be smaller, suggesting a decline. 
Marco Ugarte/Associated Press

Elizabeth Kolbert, author of the book “The Sixth Extinction,” told National Geographic that the outlook from that study is dire. It means 75% of animal species could be extinct within a few human lifetimes.

In roughly 50 years, 1,700 species of amphibians, birds, and mammals will face a higher risk of extinction because their natural habitats are shrinking.

Black Rhino
Black rhinos are critically endangered. 
Phil Noble/Reuters

By 2070, 1,700 species will lose 30% to 50% of their present habitat ranges thanks to human land use, a 2019 study found. Specifically, 886 species of amphibians, 436 species of birds, and 376 species of mammals will be affected and consequently will be at more risk of extinction.

Koalas are already “functionally extinct,” meaning the population has declined so much that it no longer plays a significant role in Australia’s ecosystem.


Anna Levan/Shutterstock

According to experts at the Australian Koala Foundation, only 80,000 koalas are left on the continent. The animals are struggling to survive in the face of deforestation, changing weather, and severe droughts.

Logging and deforestation of the Amazon rainforest is of particular concern when it comes to looming extinctions.

Amazon deforestation
An aerial view of a tract of Amazon jungle recently cleared by loggers and farmers near the city of Novo Progresso, Brazil. 
Nacho Doce/Reuters

Roughly 17% of the Amazon has been destroyed in the past five decades, mostly because humans have cut down vegetation to open land for cattle ranching, according to the World Wildlife Fund. Some 80% of the world’s species can be found in tropical rainforests like the Amazon, including the critically endangered Amur leopard. Even deforestation in a small area can cause an animal to go extinct, since some species live only in limited, isolated areas.

Every year, more than 18 million acres of forest disappear worldwide. That’s about 27 soccer fields’ worth every minute.

In addition to putting animals at risk, deforestation eliminates tree cover that helps absorb atmospheric carbon dioxide.

In the next 50 years, humans will drive so many mammal species to extinction that Earth’s evolutionary diversity won’t recover for some 3 million years, one study said.

elephant congo rainforest
African elephants like this one are frequent victims of poaching and are vulnerable to extinction. 
Kenny Katombe/Reuters

The scientists behind that study, which was published in 2018, said the planet will need between 3 million and 5 million years in a best-case scenario to get back to the level of biodiversity we have today.

Returning the planet’s biodiversity to the state it was in before modern humans evolved would take even longer — up to 7 million years.

Some paleobiologists suggested an even longer time frame for the planet’s recovery from a mass extinction: 10 million years or more.

FILE PHOTO: A newly born Mexican gray wolf cub, an endangered native species, interacts with his mother at its enclosure at the Museo del Desierto in Saltillo, Mexico on July 19, 2016. REUTERS/Daniel Becerril/File Photo
About 110 endangered Mexican gray wolves remain in the wild today. 
Thomson Reuters

A study published in the journal Nature Ecology and Evolution reveals that it took around 10 million years for Earth’s biodiversity to rebound from the mass extinction that wiped out the dinosaurs.

“Biodiversity losses won’t be replaced for millions of years, and so when you imagine extinctions in coral reef ecosystems, or rain forest ecosystems, or grasslands, or wherever, those places are going to be less diverse essentially forever, as far as humans are concerned,” Chris Lowery, a co-author of the study, told Business Insider.

Alien species are a major driver of extinctions.

zebra mussel
Zebra mussel shells pile up on a beach in Sleeping Bear Dunes National Lakeshore, Michigan. The zebra mussel is an invasive alien species in the Great Lakes. 
Corfoto/Getty Images

study published in February found that alien species are a primary driver of recent animal and plant extinctions. An alien species is the term for any kind of animal, plant, fungus, or bacteria that isn’t native to an ecosystem. Some can be invasive, meaning they cause harm to the environment to which they’re introduced.

Many invasive alien species have been unintentionally spread by humans. People can carry alien species with them from one continent, country, or region to another when they travel. Shipments of goods and cargo between places can also contribute to a species’ spread.

Zebra mussels and brown marmorated stink bugs are two examples of invasive species in the US.

The recent study showed that since the year 1500, there have been 953 global extinctions. Roughly one-third of those were at least partially because of the introduction of alien species.

Oceans absorb 93% of the extra heat that greenhouse gases trap in Earth’s atmosphere. That kills marine species and coral reefs.

Bleached coral
A bleached coral reef near Guam in the Pacific Ocean. A 2018 study found that severe bleaching outbreaks now hit reefs four times more often they did a few decades ago. 
David Burdick/NOAA/AP

Last year was the oceans’ warmest on record, and scientists recently realized that oceans are heating up 40% faster than they’d previously thought.

Higher ocean temperatures and acidification of the water cause corals to expel the algae living in their tissues and turn white, a process known as coral bleaching.

As a consequence, coral reefs — and the marine ecosystems they support — are dying. Around the world, about 50% of the world’s reefs have died over the past 30 years.

Species that live in fresh water are impacted by warming, too.

california red trout
The Goose Lake redband trout is endemic to tributaries in northeastern California and southeastern Oregon. 
Steve Howard/Getty Images

A 2013 study showed that 82% of native freshwater fish species in California were vulnerable to extinction because of climate change.

Most native fish populations are expected decline, and some will likely be driven to extinction, the study authors said. Fish species that need water colder than 70 degrees Fahrenheit to thrive are especially at risk.

Warming oceans lead to sea-level rise. Rising waters are already impacting vulnerable species’ habitats.

bramble cay melomys
The Bramble Cay melomys is the first species to go extinct because of human-driven climate change. 
nmulconray/Getty Images

Water, like most things, expands when it heats up — warmer water takes up more space. Already, the average global sea level is 5 to 8 inches higher than it was in 1900, according to Smithsonian.

In February, Australia’s environment minister officially declared a rodent called the Bramble Cay melomys to be the first species to go extinct because of human-driven climate change — specifically, sea-level rise.

The tiny rat relative was native to an island in the Queensland province, but its low-lying territory sat just 10 feet above sea level. The island was increasingly inundated by ocean water during high tides and storms, and those salt-water floods took a toll on the island’s plant life.

That flora provided the melomys with food and shelter, so the decrease in plants likely led to the animal’s demise.

Warming oceans are leading to unprecedented Arctic and Antarctic ice melt, which further contributes to sea-level rise. In the US, 17% of all threatened and endangered species are at risk because of rising seas.

FILE PHOTO: Two Adélie penguins stand atop a block of melting ice on a rocky shoreline at Cape Denison, Commonwealth Bay, in East Antarctica in this January 1, 2010 file photo.    REUTERS/Pauline Askin/File Photo
Two Adélie penguins standing atop a block of melting ice in east Antarctica. 
Pauline Askin/Reuters

Melting ice sheets could raise sea levels significantly. The Antarctic ice sheet is melting nearly six times as fast as it did in the 1980s. Greenland’s ice is melting four times faster now than it was 16 years ago. It lost more than 400 billion tons of ice in 2012 alone.

In a worst-case scenario, called a “pulse,” the glaciers that hold back Antarctica’s and Greenland’s ice sheets could collapse. That would send massive quantities of ice into the oceans, potentially leading to rapid sea-level rise around the world.

Sea-level rise threatens 233 federally protected animal and plant species in 23 coastal states across the US, according to a report from the Center for Biological Diversity. The report noted that 17% of all the US’s threatened and endangered species are vulnerable to rising sea levels and storm surges, including the Hawaiian monk seal and the loggerhead sea turtle.

If nothing is done to address climate change, one in six species is on track to go extinct.

An emperor penguin chick soaks up the warming rays of spring sunshine. 
National Geographic

An analysis published in 2015 looked at over 130 studies about declining animal populations and found that one in six species could disappear as the planet continues to heat up.

Flora and fauna from South America and Oceania are expected top be the hardest hit, while North American species would have the lowest risk.

A new study found that almost 40% of the world’s primates will be at risk of extinction due to extreme weather events associated with a warming planet.

Bornean orangutan   REUTERS Tim Chong (SINGAPORE)


According to the study, which was published in the journal Nature Climate Change, 38% of primate species — including orangutans, monkeys, and gorillas — are vulnerable to droughts and tropical cyclones.

Previous mass extinctions came with warning signs. Those indicators were very similar to what we’re seeing now.

Clouds above earth

Aleksandar Georgiev/Getty Images

The most devastating mass extinction in planetary history is called the Permian-Triassic extinction, or the “Great Dying.” It happened 252 million years ago, prior to the dawn of the dinosaurs.

During the Great Dying, roughly 90% of the Earth’s species were wiped out; less than 5% of marine species survived, and only a third of land animal species made it, according to National Geographic. The event far eclipsed the cataclysm that killed the last of the dinosaurs some 187 million years later.

But the Great Dying didn’t come out of left field.

Scientists think the mass extinction was caused by a large-scale and rapid release of greenhouse gases into the atmosphere by Siberian volcanoes, which quickly warmed the planet — so there were warning signs. In fact, a 2018 study noted that those early signs appeared as much as 700,000 years ahead of the extinction.

“There is much evidence of severe global warming, ocean acidification, and a lack of oxygen,” the study’s lead author, Wolfgang Kießling, said in a release.

Today’s changes are similar but less severe — so far.

There’s still some debate about whether we’re truly observing a sixth mass extinction.

Brazil Agent Wood Natural Resources Logging
Agent Alex Lacerda of Brazil’s Institute of Environment and Renewable Natural Resources carries a sample of wood that was confiscated at an illegal sawmill. 
Ricardo Moraes/Reuters

Scientists still argue about whether the Earth is truly in the midst of another mass extinction. Smithsonian paleontologist Doug Erwin, an expert on the Great Dying, says we’re not there yet, according to The Atlantic.

But Kolbert told National Geographic that “by the time we have definitive answers to that question, it’s possible three-quarters of all species on Earth could be gone.”

Already, there is consensus on one aspect of the extinction trend: Humans are to blame.

According to a 2014 study, current extinction rates are 1,000 times higher than they would be if humans weren’t around.

“There are very few, if any, extinctions that we know about in the last 100 years that would have taken place without human activity,” Kolbert said.

The recent United Nations report may have ended the debate.

india farmer pesticides
A farmer sprays pesticide on a paddy field at Mohanpur village, about 45 km (28 miles) west of Agartala, India, July 25, 2013. 
REUTERS/Jayanta Dey

According to the report, 75% of all land on Earth and 66% of oceans have been significantly altered by people. More than 85% of global wetland area has already been lost, and more than 79 million acres of primary or recovering forest disappeared between 2010 and 2015 alone.

This disruption and degradation of animals’ natural habitats is undoubtedly accelerating the rate of extinctions, the report authors said.

Hugh Possingham, chief scientist of The Nature Conservancy, told Business Insider that the disappearance of so many species will “fundamentally affect the global economy and the health of every human being.”

This Is Exactly What Will Happen After the Last Fish in the Ocean Dies

The devastation of the vast majority of the world’s marine life is much closer than we think.

By Mike Pearl; illustrated by Cathryn Virginia
Sep 20 2019, 3:00am

Picture a beach along the same vast ocean you know today—the same powerful waves and shifting tides, reflecting the same beautiful sunsets, even the same green-blue water. Now imagine a crowd gathered at the shoreline, standing in a big circle, gawking at something that just washed up. Kids tug on their parents’ shirt sleeves, asking questions about the dead creature lying on the sand. Reporters arrive. The story is momentous even if the takeaway isn’t much fun. Everyone knows there used to be fish in the oceans—kind of like the ones that still live in some rivers and lakes, except they could be much bigger, sometimes meaner, more diverse, more colorful, more everything. But those mythical ocean fish all died. Except maybe this one. This one was alive in there, and now it’s dead too.

According to Stanford University paleobiologist Jonathan Payne, an expert in marine mass-extinction events, a scenario where all the ocean’s fish, mammals, and other creatures—even tiny animals like krill—are all gone is far from science fiction. The type of die-off that would lead to a largely lifeless ocean has happened before, and we’re well on our way to seeing it happen again.

To get into Payne’s frame of mind, we have to look at two areas of history. First, there’s pre-dinosaur times, where we can find a precedent for the kind of huge-scale extinction we’re seeing now. Then, we have to look at the past few hundred years, to understand why our fishless future kind of looks like, uh, the present.

We know that, about 250 million years ago, some extremely bad stuff happened, because almost everything on Earth that was alive at that time died very quickly, taking only a few million years to die off. This event is not to be confused with the meteorite impact that happened 65 million years ago—the one that supposedly wiped out the dinosaurs. That was nothing. A lot of those dinosaurs never went truly extinct; they’re now known as “birds,” and quite a few mammals made it, and evolved into humans, in pretty short order. This earlier event, the Permian–Triassic Extinction, is frequently called “the Great Dying” by paleontologists who like historical events to sound like Morrissey album titles. It made the Earth pretty quiet for a while—the oceans quietest of all.

In 2017, Payne and several colleagues looked into the source of the aforementioned extremely bad stuff that led to the Great Dying. They concluded that temperature-dependent hypoxia—loss of oxygen due to changes in temperature—caused about 70 percent of the losses. An oddly familiar culprit was fingered for this temperature change: “rapid and extreme climate warming.” Payne and his pals weren’t the first to draw comparisons between the events leading up to the Great Dying and the changes we’re seeing today. A previous study had found that the Great Dying had resulted from rising carbon emissions—caused at that time by geothermal events—that occurred over the span of two to 20 millennia; in other words, the blink of a geological eye.

“The relevant thing we know from these recent results is that the patterns of warming, and loss of oxygen from the ocean that can account for the extinction at the end of the Permian are the same features we’re starting to see right now,” explained Curtis Deutsch, a chemical oceanographer at the University of Washington and one of Jonathan Payne’s colleagues on that 2017 study.

This is adapted from an excerpt out of The Day It Finally Happens. To buy this book, go here.

Thanks to our species’ multi-pronged and comprehensive approach, humanity’s present day “Kill All the Marine Life” project is going extremely well. Here’s a quick cheat sheet listing our main strategies:

  • We dump several metric tons of plastic garbage into the oceans every year.
  • Bottom trawling, or dragging fishing equipment across the seafloor, is turning “large portions of the deep continental slope into faunal deserts and highly degraded seascapes” according to a 2014 report on the long-term effects of this widespread practice
  • The planet is heating up really fast, and the resulting extinctions are happening in real time. (Although, for the record, at this rate it will take a few more centuries for this effect to reach the lifeforms at the deepest depths of the oceans.)
  • Ocean acidification—the other major side effect of CO2 emissions besides global warming—is causing countless die-offs, most famously in corals, the backbone of coral reefs, the most biodiverse ecosystems on earth.
  • Fertilizer and pesticides poison the ocean, and when combined with the above factors, they help create “dead zones,” nearly oxygen-free patches of ocean where almost nothing can live. According to a 2018 paper published in Science magazine, dead zones make up four times as much of the oceans as they did in 1950.
  • We eat the sea’s living creatures—which is the number-one cause of their declining numbers. There are rates at which we can supposedly fish sustainably—meaning in such a way that we don’t run out—but the fishing industry operates in volumes that meet, or surpass the peak equilibrium rate. (Right now, we’re hauling up 90 percent of fish stocks globally, according to the UN.) In other words, we’re killing as many fish as we possibly can as a byproduct of our industries, and then on top of that, we’re also eating as many as we can.

To be clear, the Great Dying wasn’t 100 percent caused by warming either. But whatever the cause, 286 out of 329 marine invertebrate genera we know of died back then. All the trilobites and blastoids died, for instance. Every single one! But no one mourns the trilobites and blastoids, and that actually helps illustrate why we fail to grasp that we’re annihilating life in the oceans. There’s actually a sociological term for this phenomenon: it’s called a shifting baseline.

“Shifting baselines” have to do with everyone’s gut-level perception of the natural world. The term refers to our tendency to perceive our own early experiences of ecology as the norm, in contrast to what we see later in life. To explain with a non-oceanic example, my own childhood memories of summers in California’s Inland Empire include street gutters choked with thousands of California toads. Twenty years later, those toads are mostly gone—likely decimated by chytrid fungus infections. Their loss leaves me with the false impression that the natural order in Southern California has vanished in a very short time, when actually, the damage humanity has caused here is of much longer duration and much larger in scale than the loss of one species of toad (a species that arguably wasn’t “supposed to be there” in the first place). Much more serious losses of biodiversity have been rolling out for centuries, but I don’t miss animals like the Southern California kit fox, which went extinct over a century ago, because my own baseline never included them.

Similarly, according to Deutsch, we won’t collectively care about the death of all the fish, because when it finally happens, our baselines will have shifted so much that the lack of fish will seem normal.

So back to the first question I asked those scientists: what will the fishless ocean look like?

Aesthetically, it won’t be very different, according to Payne. A point I came across again and again in my research is that crystal-clear blue waters are often relatively lifeless. It’s rare to look at the ocean and see strong indications of life—even plant life. “It’s not carpeted in green, there aren’t cells everywhere photosynthesizing,” Payne said. “The color you see is mostly just the physics of light absorption and water.” So in most places, you wouldn’t actually see anything at all by looking at the ocean, just as a flight over the Great Plains doesn’t tell you anything about the decline of the American buffalo.

Holistic accounting of the numbers of various species in the oceans have only begun recently, so it’s hard to pin down exact numbers, but according to a 2015 report by the World Wildlife Fund, the oceans lost 49 percent of all vertebrates in just the time between 1970 and 2012. So rather, we should try and imagine the perspectives of people who saw the oceans when they were teeming with life, and Deutsch suggests reading accounts from the Age of Exploration. If they could time travel, Deutsch said, the Spanish explorers who first visited the New World would look at our ocean today, and say, Wow, that’s dead.

“They would describe coming in on their ships through the Gulf of the Caribbean and not even being able to get to shore because the backs of the sea turtles were just so thick they couldn’t get their boats in,” Deutsch said. Indeed, when Columbus arrived, there were so many turtles, they thunked against the hull of his ship all night, keeping his crew awake. Today, spotting a sea turtle is a momentous event, because the number of sea turtles in the Caribbean is down to about 3 to 7 percent of what it was before Europeans arrived.

I have seen precisely one wild sea turtle in my entire life, and that was because I was searching for one.

I was off the northeast coast of Queensland, Australia, at the time, snorkeling in the Great Barrier Reef in the hopes that it might at least partially correct my own shifting baseline vis-a-vis ocean biodiversity. Even if you’ve never had the extreme privilege of visiting a coral reef, you’ve undoubtedly seen one, as magnificently CG-rendered in Finding Nemo, or majestically photographed for the BBC’s Blue Planet TV series, which means you know the broad strokes of what a coral reef is—a place so teeming with life that it’s one of the rare places for which the word “teeming” seems appropriate.

But don’t picture a technicolored Disney wonderland. Unless you have the right lens filters and the weather is just so, a coral reef just looks like what it is: a section of ocean with, well, a lot of life—like any part of the ocean you’ve ever seen, except with more brown and yellow (alive) stuff in there. When you look closely, there are the charismatic, photogenic animals down among the corals, and inside the anemones. Your expedition guide will call out when there’s something to see, “Does anyone want to see Nemo?” they’ll ask, and show off the clownfish, because clownfish are to the reef as the Eiffel Tower is to Paris. But the clownfish down there look pale and brown, and impossibly tiny, nothing like the bright red cartoon characters brought to you by Disney and Pixar. (I’m not implying that the Great Barrier Reef is anything other than breathtakingly beautiful; just that when you see it, it looks more “normal” than you might think.)

Meanwhile closer to the surface, thousands of indifferent, brownish fish dart around in schools that change directions in twitchy unison. In some parts, you can busy your hands at a coral reef by reaching out and gently closing your hand around a fish, feeling it squirm away, and then immediately grabbing another. The sheer density of “biomass” had a mounting emotional effect on me, particularly when my thoughts inevitably drifted to just how much below me had already died. Recently, 30 percent of the coral died in one year, bringing estimates of the total loss to about 50 percent. When I visited in 2018 there hadn’t been much coral bleaching recently, and lots of fish were around. The way the future is shaping up, though, finding a lot of life there is likely to become rarer and rarer.

After three hours spent touching what’s essentially a closed-off memorial to the living ocean we once had, you inevitably leave, and this gives you an opportunity to test your original perception of the ocean against your fresh memories of a marine wonderland. When you look down at the seafloor off the coast of California, you see the exact opposite of the Great Barrier Reef: bupkis. No visible fish at all. Not all patches of coastal ocean can be the Great Barrier Reef, but that doesn’t mean they should all look like lifeless deserts. To assume they should be this lifeless isn’t natural at all; that’s just your already-shifted baseline talking.

If the Great Dying is our model, the process of environmental degradation wouldn’t just mean dead marine fish, but massive die-offs in most of the plants and animals eaten by fish, meaning algae and kelp, along with many plankton, krill, worms, and everything else we tend to lump into “the bottom of the food chain.” That carnage would, in turn, devastate species that rely on small fish, like most whales, dolphins, seals, penguins, and many humans.

It’s a good time to pause and point out that some of fish species, like the coelacanth, a deep sea cave-dwelling monster fish, made it through the Great Dying and survived all the way to the present unchanged—so no, the Great Dying didn’t kill all the fish on Earth, “great” though it may have been. It was just a very large-scale mass extinction. But as long as we’re being pedantic, keep in mind that fish can’t all be lumped into any single taxonomic category like phylum, class, order, or family. From a certain genetic perspective, a shark has more of an obvious connection to its fellow cunning predator the seahorse (look it up) than with a coelacanth, and a coelacanth shares DNA with a salamander that it doesn’t share with a shark. So when I say “fish” I’m casting a very wide net (pun intended) that includes all marine vertebrates with gills that aren’t tetrapods—so no salamanders. That might not mean much to you, but if any jargon-crazed biologists are reading this, they’ll be glad I’m making this distinction.

And with the Great Dying as our model, we’re imagining the disappearance of about 96 percent of all life in the ocean—not just fish, but just about everything down there with eyes (and a lot of blind species, too). What happens?

Well, in some ways this will be a vastly improved business environment for large corporations. Just as the overabundance of marine life in oceans around the New World was bad for business, today’s ships also run into problems.

For one example, let’s look at retailers that ship globally like Walmart, Amazon, and Alibaba, which increasingly face regulations aimed at preserving marine animal habitats. The container ships—which are the size of a small town—that move merchandise currently have to plot out inconvenient routes to circumvent certain animal habitats, and to avoid some forms of water pollution caused by their 100,000 horsepower diesel engines. And they must carve a path through the seas without making sounds that are too loud, or that fall below 100 hertz because animals like whales use those frequencies to communicate. In the heated, acidified ocean that has killed all fish, baleen whales will have certainly starved to death long ago, obviating the need for any such regulations. The die-off will also allow for the easing of regulations against sewage dumping, and—needless to say—negate most of the public’s antipathy toward oil spills.

That’s not to say that businesses will make more money and that’s that. Environmental remediation, a term that means “cleaning up after businesses that pollute,” is currently a growing industry, with some market researchers claiming it’ll be worth as much as $123.13 billion by the year 2022—an amount that’s almost equal to Google’s 2017 revenue. Some of those profits will obviously fall away when there’s much less demand for oil spills to be cleaned up. But it’s not clear how long the mostly dead oceans could be treated as free and open spaces to dump things.


We can safely predict one very large effect of all that dumping: the marine fishing industry will no longer involve “fishing.” It may nonetheless survive with the help of fish aquaculture.

Fish farms appear to be a growing business. Just look at “Bluefin tuna,” the marketing term used to describe several giant, silvery fish—all endangered or threatened—that we hoist onto ships, carve up by the thousands every day to extract the $15 morsels of fatty tuna we label on menus with the Japanese word “toro,” and serve for the gustatory pleasure of the wealthy inhabitants of coastal cities around the world. Those morsels are about to become even more effective advertisements of wealth when the three or four species of fish they come from go extinct in the wild sometime in the next few decades, and prices skyrocket.

To mitigate this inconvenience, projects exist today to grow Bluefin tuna in tanks, like the ones at Yoni Zohar’s marine technology lab at the University of Maryland, Baltimore County. The purpose, currently, is to grow fish larvae, including bluefins, along with smaller species like sea bass, into viable juvenile fish that can be taken out in boats and tossed into overfished bluefin habitats to replenish the depleted population. But this plan will only work as long as the ocean can sustain schools of wild tuna, which it won’t be able to for much longer. The death knell has been sounded for even the more plentiful albacore, and the yellowfin species marketed as “ahi,” both of which are declining in number as well. That means tanks like Zohar’s have to evolve if these luxury consumer goods are going to continue to exist. Tuna will have to survive in their tanks for multiple decades—long enough to transform from a microscopic and inedible hatchling to a 400 kilogram titan with fatty, palate-pleasing jowl meat. Making the feat even more problematic is that they never stop swimming, which is no big deal when the fish are tiny, but will be harder to accommodate in a tank when they’re capable of swimming at speeds exceeding 70 kilometers per hour.

In the case of something like a dolphin, this sort of small-tank captivity is viewed as cruel, but fish taste better than dolphins, and don’t squeak happily at children, so, much as has been the case with cows in the U.S., it’s doubtful anyone will take an interest in their welfare. We can probably expect vast factory farms full of tuna, along with any other large marine fish humans want to continue to eat in the future since there’s no alternative, apart from not eating them.

But if we move away from looking at the ocean as a business, it bears mentioning that not eating any fish whatsoever is decidedly not an option for a vast swath of humanity. “You’d be looking at a lot of starvation,” Payne, the Stanford paleobiologist, told me. According to a 2016 op-ed in Science magazine by public health researcher Christopher Golden, 845 million people—about a tenth of the global population—face some form of malnutrition in the near future when traditional fishing ceases to be a viable source of food for many of the world’s poor.

We’re also in for more big changes to the weather, Payne said. Part of the reason the oceans work as a “carbon sink” is that plankton consume carbon as a part of photosynthesis, turning them into organic matter. A reduction in photosynthesis means more carbon will just stay in the atmosphere and speed up global warming, particularly in the vast dead zone around the equator—a probable cause of the extreme ocean temperatures of the Great Dying; areas that are now usually around 28 degrees Celsius were 40 degrees Celsius or more back then.

Apart from heat, Payne said, “one thing you would see very quickly is the effect of storms on coastal systems would change, because with nothing living on the reefs, the reefs will start to fall apart. That will reduce their ability to protect coastal systems from waves during big storms.” This means huge changes in the terrestrial climate near these coastal systems, particularly in places like Australia and the Bahamas.

But even with the combined ocean ecosystem more or less converted into a giant marine desert, there’s a very good chance we’ll always have a man-made oasis or two. A 2017 proposal by the consortium of tourism businesses and Australia’s Reef and Rainforest Research Centre would protect six particularly profitable sites along the reef by literally pumping in cold water at a cost of millions of dollars to lessen the effects of climate change. The idea has been regarded as perverse, with critics noting that pumping cold water into a few areas of the Great Barrier Reef would be nothing but a band-aid, and that large scale action is needed. But large scale action isn’t happening, and the mass die-off is proceeding.

Since it appears we lack the willpower to curb our worst impulses when it comes to the oceans, a few band-aids may be all we can hope for.

Adapted from an excerpt from The Day It Finally Happens by Mike Pearl. Copyright © 2019 by Mike Pearl. Reprinted by permission of Scribner, an Imprint of Simon & Schuster, Inc.

A sliver of the atmosphere is about to cause big problems on Earth

That percentage of CO2 isn’t as small as you think.


I heard that carbon dioxide makes up 0.04% of the world’s atmosphere. Not 0.4% or 4%, but 0.04%! How can it be so important in global warming if it’s such a small percentage?

I am often asked how carbon dioxide can have an important effect on global climate when its concentration is so small — just 0.041% of Earth’s atmosphere. And human activities are responsible for just 32% of that amount.

I study the importance of atmospheric gases for air pollution and climate change. The key to carbon dioxide’s strong influence on climate is its ability to absorb heat emitted from our planet’s surface, keeping it from escaping out to space.

“Keeling Curve”
The “Keeling Curve,” named for scientist Charles David Keeling, tracks the accumulation of carbon dioxide in Earth’s atmosphere, measured in parts per million.

Early greenhouse science

The scientists who first identified carbon dioxide’s importance for climate in the 1850s were also surprised by its influence. Working separately, John Tyndall in England and Eunice Foote in the United States found that carbon dioxide, water vapor, and methane all absorbed heat, while more abundant gases did not.

Scientists had already calculated that the Earth was about 59 degrees Fahrenheit (33 degrees Celsius) warmer than it should be, given the amount of sunlight reaching its surface. The best explanation for that discrepancy was that the atmosphere retained heat to warm the planet.

Tyndall and Foote showed that nitrogen and oxygen, which together account for 99% of the atmosphere, had essentially no influence on Earth’s temperature because they did not absorb heat. Rather, they found that gases present in much smaller concentrations were entirely responsible for maintaining temperatures that made the Earth habitable, by trapping heat to create a nat

A blanket in the atmosphere

Earth constantly receives energy from the sun and radiates it back into space. For the planet’s temperature to remain constant, the net heat it receives from the sun must be balanced by outgoing heat that it gives off.

Since the sun is hot, it gives off energy in the form of shortwave radiation at mainly ultraviolet and visible wavelengths. Earth is much cooler, so it emits heat as infrared radiation, which has longer wavelengths.

electromagnetic spectrum
The electromagnetic spectrum is the range of all types of EM radiation — energy that travels and spreads out as it goes. The sun is much hotter than the Earth, so it emits radiation at a higher energy level, which has a shorter wavelength.

Carbon dioxide and other heat-trapping gases have molecular structures that enable them to absorb infrared radiation. The bonds between atoms in a molecule can vibrate in particular ways, like the pitch of a piano string. When the energy of a photon corresponds to the frequency of the molecule, it is absorbed and its energy transfers to the molecule.

Carbon dioxide and other heat-trapping gases have three or more atoms and frequencies that correspond to infrared radiation emitted by Earth. Oxygen and nitrogen, with just two atoms in their molecules, do not absorb infrared radiation.

Most incoming shortwave radiation from the sun passes through the atmosphere without being absorbed. But most outgoing infrared radiation is absorbed by heat-trapping gases in the atmosphere. Then they can release, or re-radiate, that heat. Some returns to Earth’s surface, keeping it warmer than it would be otherwise.

Earth receives solar energy from the sun (yellow) and returns energy back to space by reflecting some incoming light and radiating heat (red). Greenhouse gases trap some of that heat and return it to the planet’s surface.
Earth receives solar energy from the sun (yellow) and returns energy back to space by reflecting some incoming light and radiating heat (red). Greenhouse gases trap some of that heat and return it to the planet’s surface.

Research on heat transmission

During the Cold War, the absorption of infrared radiation by many different gases was studied extensively. The work was led by the US Air Force, which was developing heat-seeking missiles and needed to understand how to detect heat passing through air.

This research enabled scientists to understand the climate and atmospheric composition of all planets in the solar system by observing their infrared signatures. For example, Venus is about 870 degrees F (470 degrees C) because its thick atmosphere is 96.5% carbon dioxide.

It also informed weather forecast and climate models, allowing them to quantify how much infrared radiation is retained in the atmosphere and returned to Earth’s surface.

People sometimes ask me why carbon dioxide is important for climate, given that water vapor absorbs more infrared radiation and the two gases absorb at several of the same wavelengths. The reason is that Earth’s upper atmosphere controls the radiation that escapes to space. The upper atmosphere is much less dense and contains much less water vapor than near the ground, which means that adding more carbon dioxide significantly influences how much infrared radiation escapes to space.

Carbon dioxide levels rise and fall around the world, changing seasonally with plant growth and decay.

Observing the greenhouse effect

Have you ever noticed that deserts are often colder at night than forests, even if their average temperatures are the same? Without much water vapor in the atmosphere over deserts, the radiation they give off escapes readily to space. In more humid regions, radiation from the surface is trapped by water vapor in the air. Similarly, cloudy nights tend to be warmer than clear nights because more water vapor is present.

The influence of carbon dioxide can be seen in past changes in climate. Ice cores from over the past million years have shown that carbon dioxide concentrations were high during warm periods — about 0.028%. During ice ages, when the Earth was roughly 7 to 13 degrees F (4-7 degrees C) cooler than in the 20th century, carbon dioxide made up only about 0.018% of the atmosphere.

Even though water vapor is more important for the natural greenhouse effect, changes in carbon dioxide have driven past temperature changes. In contrast, water vapor levels in the atmosphere respond to temperature. As Earth becomes warmer, its atmosphere can hold more water vapor, which amplifies the initial warming in a process called the “water vapor feedback.” Variations in carbon dioxide have, therefore, been the controlling influence on past climate changes.

Small change, big effects

It shouldn’t be surprising that a small amount of carbon dioxide in the atmosphere can have a big effect. We take pills that are a tiny fraction of our body mass and expect them to affect us.

Today, the level of carbon dioxide is higher than at any time in human history. Scientists widely agree that Earth’s average surface temperature has already increased by about 2 degrees F (1 degree C) since the 1880s, and that human-caused increases in carbon dioxide and other heat-trapping gases are extremely likely to be responsible.

Without action to control emissions, carbon dioxide might reach 0.1% of the atmosphere by 2100, more than triple the level before the Industrial Revolution. This would be a faster change than transitions in Earth’s past that had huge consequences. Without action, this little sliver of the atmosphere will cause big problems.

U.S., Canada have lost 3 billion birds since 1970. Scientists say ‘nature is unraveling.’

“It’s an empty feeling in your stomach that these same birds that you grew up with just aren’t there anymore.”
Image: Common Nighthawk

The population of birds at the start of breeding season in the U.S. and Canada has fallen from just over 10 billion to a little more than 7 billion in the last 50 years. Above, a common nighthawk.Joaquin Paredes / 500px / Getty Images/500px Plus