Saturday, July 31, 2021

Wild Free and Happy Sample 55

[Note: This is the fifty-fifth sample from my rough draft of a far from finished new book, Wild, Free, & Happy.  The Search field on the right side will find words in the full contents of all rants and reviews.  These samples are not freestanding pieces.  They will be easier to understand if you start with sample 01, and follow the sequence listed HERE — if you happen to have some free time.  If you prefer audiobooks, Michael Dowd is in the process of reading and recording my book HERE.

CLIMATE CRISIS

The focus of this book is human eco-history.  Climate change has influenced our journey since day one, when our tree-dwelling ancestors had to move onto the savannah.  Today’s crisis is climate change on steroids.  It’s doing things that humans have never experienced before — countless huge, accelerating, scary, uncontrollable changes that we don’t fully comprehend.  Our beloved techno magic is incompetent to cleverly swish the bad stuff away.  Say hello to a thrilling future of big surprises.

For many folks, the climate crisis is not chasing them down the alley every day, snarling and viciously snapping at their asses.  Now and then we hear stories and see some pictures.  News sources tend to quietly step around the embarrassing subject.  Too much yucky news can make their audience uncomfortable and unfaithful.  We get some peeks at reality now and then, but most of the story remains behind closed curtains.

For many, the crisis can seem like a wee dark cloud on the distant horizon.  Day to day life in the cubicle farm, or the family room, is rarely affected.  But, if you make an effort to listen, the jungle drums are regularly talking about highly improbable flash floods, hundred year storms, persistent droughts, unprecedented heat spells, landslides, etc.  These weird stories from outer space can often seem impossible, unbelievable, and deniable.

The climate crisis is not a sudden asteroid-strike event, like the destruction of the World Trade Center towers in 2001.  It’s a vastly bigger and stronger disturbance that will eventually be affecting everyone, everything, everywhere, to a breathtaking degree, and causing much irreversible damage.  It’s the unintentional result of way too many people, living way too hard, for way too long.

Hopium addicts jabber about “solving” the climate crisis, and looking forward to a sustainable green future.  There is nothing that the magicians of technology cannot fix.  Hope fiends have blind faith that “it’s not too late.”  Buy an electric car, put solar panels on your roof, shop like there’s no tomorrow, and enjoy a long and fabulous life. 

The dreamy perceptions of these hope fiends reflects a deficit of understanding, in combination with the Tinker Bell Effect.  In the Peter Pan story, Tinker Bell is the fluttering fairy of magical thinking, “Just think a happy thought and you can fly!”  Albert Bartlett was amused by the popular fantasy that if you called something “sustainable” enough times, then <shazaam!> it was!

Megan Seibert and William Rees did an excellent job of explaining why sustainable alternative energy visions are neither sustainable nor possible.  Their report describes why “the pat notion of ‘affordable clean energy’ views the world through a narrow keyhole that is blind to innumerable economic, ecological, and social costs.”  Alice Friedemann examined the alternative energy options, and described why none of them were an effective or realistic solution.

In addition to the hopium addicts are the shameless bullshit hucksters.  They are supported by wealthy interests that want to keep the planet-thrashing status quo on life support ventilators for as long as humanly possible.  Their cash cows produce generous profits, but exist at the expense of the family of life.  Bullshit artists have been highly successful at sowing the seeds of doubt.  Climate change is a hoax promoted by devil worshippers!  We’re regularly splattered with a firehose of deliberate misinformation.

The unfortunate reality is that 7.8 billion people cannot simply think a happy thought and become ecologically harmless.  Climate change is the stinky steaming 100 ton turd in the swimming pool.  It horrifies us, because it rubbishes our fantasies of human supremacy, endless progress, and the best is yet to come.  It makes our beloved “high standard of living” look like an insanely stupid hallucination (which it is) — a reckless high speed joyride that leaves the planet in ruins.

The climate crisis is an enormous fast-moving subject that is generating a staggering amount of articles, reports, books, and videos.  The future has yet to be written, but a number of current trends have a clear trajectory — warming climate, melting ice, thawing permafrost, rising seas, extreme weather events, etc.  I’m not going to play the prophet game, but I do feel obligated to point out some critical climate-oriented trends that obviously appear to be on a treacherous path. 

The information on the following pages is a very rough sketch, like a cop’s bodycam video of a chaotic crime scene.  It’s written at one moment in time, from one perspective, and is far from complete.  My plan here is to present a sampler of core ideas, and toss in links to interesting sources.  Readers who want to further explore the issue can follow the links, and feed their hungry brains. 

Albedo

When incoming sunbeams hit white regions of ice and snow, some of the heat is reflected away from the planet, back into outer space.  This ability to reflect is called albedo.  Fresh snow, which is very white, reflects 80 to 90 percent of incoming heat.  So, it has an albedo of 0.8 to 0.9.  Ice that has been bare for a while accumulates soot and dust, which makes it darker, less reflective.  It has an albedo of 0.4 to 0.7.  Sea water and dry land are darker, absorb more incoming heat, and then radiate it.  Open water has an albedo of 0.1. 

When albedo reflectivity is diminished, more heat can enter the atmosphere and accumulate.  Ice gets thinner, breaks up, and retreats.  Then, more solar heat can hit more open water or bare ground.  More of the thick ice that used to exist year-round now melts away during the warmer months.  The duration of ice-free summer periods is lengthening.  This pattern is called a positive feedback loop — more warmth, more melting, more warmth, etc….  It’s the engine of runaway warming, the arctic death spiral.

Arctic Ice

In 1968, the Apollo-8 mission orbited the moon, and took the first photo of the Earth rising above the moon’s horizon.  In that photo, Earth was white around both the north and south poles.  Today, when it’s summer in the Northern Hemisphere, the view from outer space shows a white Antarctic, and a blue Arctic.  As it melts, the ancient northern ice sheet is gradually becoming an open ocean.  With a stampede of well-intended, highly-destructive booboos, human cleverness and runaway warming are changing the planet, and the future.

Peter Wadhams has been studying Arctic ice for 50 years.  He has a way-above-average understanding of the danger we’re in.  He’s been working hard to alert us, but not many are getting the message.  Arctic ice is extremely precious, because it’s essential for maintaining vital climate balances.  Its cool temperature, and highly reflective whiteness, have enabled the existence of life as we know it. 

Over the last 70,000 years, climate trends have typically been a zigzag pattern of frequent erratic swings, hot-cold-hot-cold….  Today, we are living in the rear end of an 11,700 year era of unusually stabile warm temperatures — a weird deviation that enabled the emergence of fairly reliable agriculture, and allowed 7.8 billion people to survive at the same time (temporarily).  The long-term trends imply that we’re long overdue for a new ice age.  Fat chance!  Instead, we’re speeding out of control down the hot lane.

The planet is sliding down the path to a largely ice-free Arctic.  A few decades ago, the North Pole as covered with ice 10 to 12 feet thick.  No more.  “With the steady disappearance of polar ice cover, we are losing a vast air conditioning system that stabilized the climate for thousands of years.”  We have been living in “the Goldilocks climate” — not too hot, not too cold, just right!  That pattern has been disrupted by rapidly overloading the atmosphere with ancient carbon.

Wadhams lamented, “We are fast approaching the stage when climate change will be playing the tune for us while we stand by and watch helplessly, with our reductions in CO2 emissions having no effect.”  In 2016, he wrote a short and easy to understand summary of his findings, with excellent illustrations.  I strongly recommend checking it out [HERE].  YouTube also has many Wadhams videos.

Morgan McFall-Johnsen described the rapid melting of Greenland’s ice in 2019.  That year, in just five days, 55 billion tons of melt water rushed out of Greenland’s ice sheet, “enough to cover the state of Florida in almost 5 inches of water.”  In their most pessimistic scenario, scientists had predicted that this level of melting would not be reached until 2070.  We did it 50 years ahead of schedule!  “The Arctic is warming almost twice as quickly as the global average.”    The times are changing.  Trouble ahead. 

Greenhouse Gases

Under normal natural conditions, CO2 is precious.  If there was no CO2, there would be no plants or animals.  During photosynthesis, plants take in CO2 and emit oxygen.  At the same time, animals breathe in oxygen and exhale CO2.  It’s a harmonious circle dance, normally.  But the balance gets blasted when we extract millions of years of ancient carbon from deep underground, burn it, and totally overload the atmosphere.

The atmosphere is also precious.  It allows incoming solar heat to pass through, and warm the planet below, which enables the survival of the family of life.  It also allows some heat to escape back into outer space, but not as much as it lets in.  So, the atmosphere acts like a comfortable greenhouse.  Wadhams noted that if Earth had no atmosphere, it would be a lifeless frozen planet.  The moon is a frigid place because it has no atmosphere, and its average temperature is -4°F (-18°C).  Earth’s lovely atmosphere enables an average temperature of 59°F (15°C).

There are several compounds that help the greenhouse maintain a happy climate.  In normal times, the greenhouse is wonderful magic act.  In crazy times, greenhouse gas overloads can disrupt the global party.  The four main greenhouse gases are carbon dioxide (CO2) methane (CH4), nitrous oxide (N2O), and water vapor (H2O).  CO2 is responsible for maybe 55 percent of the current imbalance.  In preindustrial times, CO2 levels in the atmosphere were 280 ppm (parts per million).  In 2021 they reached 420 ppm — estimated to be the highest concentration in more than 3 million years (or 4 million, or 15 million).

Methane levels are also soaring, from preindustrial 700 ppb (parts per billion) to around 2,000 ppb in 2019.  Methane remains in the atmosphere for 7 to 10 years, during which its impact can be 100 to 200 times worse than CO2.  Then, it breaks down into CO2, which can remain in the atmosphere much longer.  When methane’s brief existence is calculated within a hundred year timeframe, its impact is 23 times worse than the hundred year impact of CO2

Nitrous oxide is a minor offender, found at about 300 ppb in the atmosphere, where it can remain for 120 years.  Its source is primarily synthetic nitrogen fertilizers. 

Water vapor can act like an insulating blanket.  As the Arctic warms, its air can hold more moisture, and a layer of water vapor (clouds) helps to retain warm air.

The bottom line here is that manmade carbon emissions have been working hard to turn the delightful greenhouse into an overheated hothouse.  Too much heat is being retained in the atmosphere, frigid regions are melting, and a slippery hideous crisis has popped out of the womb screaming.

The good news here is that we are beginning to learn a very important lesson.  Mistakes can be fabulous teachers.  The bad news is that we are learning this at a time when a growing number of experts believe that the crisis is already past the point of no return, off the leash, sprinting away, disregarding our frantic commands.  Far too late, the wizards have discovered that the unusually warm and stable climate that we used to enjoy was possible because of a priceless treasure of snow and ice, which is now riding off into the sunset. 

Clouds

Fred Pearce described how clouds also play a role in the greenhouse magic act.  When the sun is shining, bright clouds can reflect away 30 to 60 percent of incoming solar heat.  Over the seas, stratus and stratocumulus clouds shade the ocean, so less heat is absorbed by the water.  During the day, low clouds provide cooling shade, but after sunset they become a heat retaining blanket. 

Whether clouds make shade or trap heat “depends on how reflective they are, how high they are, and whether it is day or night.”  Until recently, experts believed that the conflicting effects of clouds were about equal, so they balanced out.  That belief is going extinct.

Satellite data from NASA indicates that since 2013, cloud cover over the oceans has declined, at the same time that global average temperatures have risen sharply.  Other studies indicate that in warmer years, there are fewer low-level clouds in the tropics.  This indicates that in a warming climate, clouds are expected to get thinner, completely burn off, or not form at all.  This would lead to even higher temperatures, and faster global warming — a positive feedback loop of more heat, less clouds, more heat….

Pearce wrote, “Recent climate models project that a doubling of atmospheric CO2 above pre-industrial levels could cause temperatures to soar far above previous estimates.”  In pre-industrial times, CO2 levels in the atmosphere were 280 ppm.  Double that would be 560 ppm.  In 2021 they reached 420 ppm.  The higher they go, the hotter it gets, the fewer the clouds….

Carbon Emissions Skyrocket

As described in earlier chapters, our ancestors began acting like odd animals long, long ago.  Our quirky path picked up momentum with fire making, the domestication of plants and animals, and the emergence of civilization.  The turbo thrusters ignited with the arrival of the Industrial Revolution, when we plunged headlong into the brave new world of fossil energy.  With this shift, more and more carbon was emitted by human activity, and absorbed by the oceans, atmosphere, and greenery.

The twentieth century was radically different from all previous time.  Foolishly raiding a massive 500 million year treasure chest of highly potent energy enabled the rapid development of countless planet-thrashing technologies.  Unencumbered by foresight, dangerously clever humans looted the ancient hydrocarbon cemeteries, hauled much of the buried treasure into the daylight world, and burned it — to enjoy a brief, fantastically ridiculous, explosion of childish decadence.

In 2000, environmental historian J. R. McNeill wrote an eco-obituary for the twentieth century, Something New Under the Sun.  This book revealed the nightmares that exploded during that century from hell.  Later, as the years clicked past, McNeill realized that his book did not say enough.  The years following World War II were so spectacularly insane that they made the first 45 years of the century look somewhat wholesome.

So, in 2014, McNeill and Peter Engelke published The Great Acceleration, which focused on the era after 1945, when the poop slammed hard into the fan.  This era was the freak show in which I have spent my life’s journey, the freak show when the human population more than tripled, the freak show that the living generation perceives to be the normal way of life.

They wrote that in 1750, when the Industrial Revolution was still in diapers, 3 million tons of carbon were released into the atmosphere each year.  By 1850, emissions soared to 50 million tons.  It was 1,200 million tons in 1950, 4,000 million in 1970, and 9,500 million by 2015.  How smart was that? 

Steven Koonin noted that of the CO2 we emit today, between 30 and 55 percent will still be in the atmosphere 100 years from now, and between 15 and 30 percent will remain for 1,000 years.  It does not promptly dissipate, so ongoing emissions ratchet up the concentration in the atmosphere.  Reducing emissions only slows the increase.  The gearshift has no reverse.

Each year, about 37 billion tons of CO2 are emitted.  At this rate, the concentration in the atmosphere would increase by about 2 ppm in a year.  Year after year, more is added.  A portion of these emissions remain in the atmosphere for centuries, so their concentration continuously grows.  The current trajectory of greenhouse gas emissions is on a path to double by 2075.  

Billions continue living like its 1999.  Ignorance is bliss.  John Gowdy concluded, “The effects of fossil fuel burning are irreversible on a time scale relevant to humans.”  We’ve started something we cannot stop. 

Terrestrial Permafrost

Peter Wadhams noted that permafrost is buried under dry land across the Arctic, spread across an area of 7.3 million square miles (19 million km2), something like the combined land area of Russia and Argentina.  As Arctic temperatures soar, the permafrost is rapidly thawing (it does not “melt”).  Soils in this permafrost contain lots of organic carbon, plant material that lived in ages past, but froze before fully decomposing.  Unlike offshore (sea bottom) permafrost, terrestrial permafrost does not contain frozen methane.  But when it thaws and decays, microbial life can then create and emit CO2, methane, and nitrous oxide. 

Susan Natali, an Arctic ecologist, studies permafrost, climate change, and greenhouse gases.  In the Northern Hemisphere, about 25 percent of the land area sits above permafrost, a layer of frozen soil, rocks, water, and organic material.  Some of it has been frozen for up to 40,000 years.  Permafrost contains about 1,500 billion tons of carbon — twice as much as the carbon already in the atmosphere, and three times as much as the carbon stored in the world’s forest biomass.

Temperatures in the Arctic are rising twice as fast as they are in the rest of the world, a trend likely to continue indefinitely.  This warming is thawing the upper layers of permafrost.  “Not all of the carbon that’s in permafrost will be released.  Our current expectations is about 10 to 15 percent of that carbon will be released into the atmosphere.  That said, if all of the carbon of permafrost was released, at that point, this is not going to be a habitable planet for humans.”

Craig Welch also commented on the daunting speed at which Arctic permafrost is thawing.  Until recently, scientists expected the rate of thawing to be gradual.  Reality disagrees.  When forest soils thaw and soften, trees get wobbly as root systems destabilize.  These “drunken trees” will eventually fall down.  When frozen slopes thaw, landslides happen, exposing the bones of mammoths and other ancient critters. 

Abrupt thaw increases the number of massive ground slumps.  These depressions collect melt water and rain, creating new ponds and lakes.  Bubbles of methane and CO2 rise up out of the mud beneath the water.  As the climate warms, and Arctic lakes grow in size and number, greenhouse gas emissions from permafrost could triple.

Ed Struzik notes that permafrost consists of up to 80 percent frozen water.  When permafrost thaws, the land can turn to mud.  Craters up to the size of football stadiums are forming in the tundra, as the land sinks.  The Batagaika Crater in the Yana River Basin of Siberia is 0.6 miles (1 km) long, and 109 yards (100 m) deep.  These thaw slumps or landslides are increasing.  Stream flows are changing, and seashores are collapsing.  In the Northwest Territories, when a rapidly thawing cliff bordering the shores of a tundra lake collapsed, the 800,000 gallon lake drained in two hours.  In the Mackenzie River Delta, up to 15,000 of the 45,000 lakes are expected to dry up. 

With warming, willows and shrubs are now displacing tundra vegetation, which includes cranberries, blueberries, cloudberries, shrubs, sedges, and lichen.  This is affecting wildlife.  In 2006, there were 3,000 caribou on the Tuktoyaktuk Peninsula, now there are half as many.  They have less lichen to eat.  Musk oxen in Canada and reindeer in Siberia seem to be dying from ancient pathogens that are coming back to life. 

The U.S. Geological Survey wrote an excellent 68 page report on thermokarst.  This is a fairly new landform in the Northern Hemisphere that has come into existence since the 1980s.  Thermokarst is created as permafrost thaws, and the land surface changes in 23 different ways.  Common characteristics include lakes, sinkholes, pits, landslides, collapsed pingos, etc.  (See Wikipedia’s thermokarst page for breathtaking photos of massive permafrost melting.)

Louise Farquharson and team studied thermokarst development in the Canadian High Arctic.  They studied land that had been frozen for thousands of years.  Until recently, the buried permafrost had been in equilibrium with the climate.  They were surprised to find that, thanks to rising temperatures, permafrost thawing was reaching depths that were not predicted for another 70 years.  “Our data show that very cold permafrost (<10°C) at high latitudes is highly vulnerable to rapid nearsurface permafrost degradation due to climate change.”

Dahr Jamail is a nomadic journalist who writes powerful stories from the front lines of the climate blitzkrieg.  He visited the Inupiat village of Utqiagvik, Alaska.  The original village is collapsing into the sea, because the solid permafrost it was built on thawed and turned to pudding.  The new village is also destined to tumble into the sea.  Polar bears are gone.

A gravedigger said that in the past, solid permafrost was close to the surface.  It used to take three days of chopping to dig a grave.  Now it takes five hours.  “Roads, railroads, oil and gas infrastructure, airports, seaports, all these things were built across the Arctic on the assumption that the permafrost would stay frozen.”  Ooops!

Offshore Permafrost

In addition to terrestrial permafrost, there is also offshore permafrost, which lies beneath seabed sediments.  It originally formed under dry land thousands of years ago, when sea levels were much lower.  Offshore is what gives Peter Wadhams screaming nightmares.  It contains substantial amounts of methane hydrates (also called methane clathrates), and it is especially vulnerable to thawing as sea ice retreats, and water temperatures rise. 

Methane hydrates are frozen crystals of methane that will melt and burn when close to a flame.  They look like ice.  An estimated 10,400 gigatons of methane are stored in hydrate deposits.  When hydrate crystals melt, the methane is released.  In the entire Arctic Ocean, the hydrate deposits are estimated to contain 13 times the amount of carbon currently present in the atmosphere. 

Wadhams is especially focused on the East Siberian Arctic Shelf.  In the East Siberian Sea, this shelf consists of 810,000 square miles (2.1 million km2) of shallow water, of which 75 percent is less than 130 feet (40 m) deep.  In the good old days, the entire sea used to be covered year round with surface ice, which kept the water frigid or frozen.  This changed in 2005, when summer sea ice began disappearing, exposing seawater to the atmosphere.  Sunlight could now penetrate directly into the water and warm it.  Shallow waters warm faster than deeper areas.

For the first time in tens of thousands of years, warmer water could reach shallow regions of the seabed, causing permafrost to thaw.  As permafrost thawed, the frozen methane hydrates began melting, releasing plumes of methane bubbles.  In waters deeper than 330 feet (100 m), the methane oxidizes while rising, and the plume disappears before reaching the surface.  In the shallows, bubble plumes make it to the surface, and methane is released into the atmosphere. 

In a 2016 article, Wadhams described the possibility of a sudden catastrophic methane release from the East Siberian Sea.  Researchers “fear that a pulse of up to 50 gigatons of methane — some 8 percent of the estimated stock in the Arctic sediments — could be released within a very few years, starting soon.”  This would generate a surge of warming.  Russian scientists on site calculate that the probability of this is at least 50 percent.

[To be continued.  This chapter will contain 3 or 4 more segments.] 

6 comments:

Thom Hawkins said...

Mega Disasters: Global Glacier Meltdown (S2, E7) | Full Episode | History Channel
Just released on YouTube...keep in mind this was made before the current extreme heat that is melting glaciers even faster than depicted here. Also no mention here of the global forest fires that darken glaciers with ash & soot and warm them even more. As foreboding as this depiction is, it is even worse. But at least The History Channel is getting some hard truths out to the public with visuals they can understand.

What Is Sustainable said...

Hi Thom! Yes, coverage is picking up. Much of it seems to conclude that it’s time for change — that it’s not impossible to fix it, and it can be fixed without sacrificing our beloved indulgences. Even if that was true (and it isn’t), changing the culture, lifestyles, and habits of billions of folks is… unlikely (ahem). Even if we totally shutdown civilization today, the CO2 would keep rising, temps would keep rising, ice would keep melting. That’s the message I’m getting after reading over 100 papers and articles, and five books.

uuubigdummy said...

I like the Tinkerbell thinking about it

.

The climate crisis is not a sudden asteroid-strike event, like the destruction of the World Trade Center towers in 2001. It’s a vastly bigger and stronger disturbance that will eventually be affecting everyone, everything, everywhere, to a breathtaking degree, and causing much irreversible damage. It’s the unintentional result of way too many people, living way too hard, for way too long.

Hopium addicts jabber about “solving” the climate crisis, and looking forward to a sustainable green future. There is nothing that the magicians of technology cannot fix. Hope fiends have blind faith that “it’s not too late.” Buy an electric car, put solar panels on your roof, shop like there’s no tomorrow, and enjoy a long and fabulous life.

The dreamy perceptions of these hope fiends reflects a deficit of understanding,

in combination with the Tinker Bell Effect.

In the Peter Pan story, Tinker Bell is the fluttering fairy of magical thinking,

“Just think a happy thought and you can fly!”
Albert Bartlett was amused by the popular fantasy that

if you called something “sustainable” enough times, then it was!

Megan Seibert and William Rees did an excellent job of explaining why sustainable alternative energy visions are neither sustainable nor possible. Their report describes why “the pat notion of ‘affordable clean energy’ views the world through a narrow keyhole that is blind to innumerable economic, ecological, and social costs.” Alice Friedemann examined the alternative energy options, and described why none of them were an effective or realistic solution.

In addition to the hopium addicts are the shameless bullshit hucksters. They are supported by wealthy interests that want to keep the planet-thrashing status quo on life support ventilators for as long as humanly possible. Their cash cows produce generous profits, but exist at the expense of the family of life. Bullshit artists have been highly successful at sowing the seeds of doubt. Climate change is a hoax promoted by devil worshippers! We’re regularly splattered with a firehose of deliberate misinformation.

The unfortunate reality is that 7.8 billion people cannot simply think a happy thought and become ecologically harmless. Climate change is the stinky steaming 100 ton turd in the swimming pool. It horrifies us, because it rubbishes our fantasies of human supremacy, endless progress, and the best is yet to come. It makes our beloved “high standard of living” look like an insanely stupid hallucination (which it is) — a reckless high speed joyride that leaves the planet in ruins.

Steve Carrow said...

Just wondering about some numbers. 9.7 billion tons of CO2 per year is stated for 2015, but a couple paragraphs later, 37 billion tons per year is stated. Is that right?

What Is Sustainable said...

I don't find 9.7 billion in this file.

What Is Sustainable said...

Steve, my sources are below. Estimating something as vast as global CO2 emissions can only be estimations or wild guesses.

Then after 1945 humankind embarked upon a fiesta of fossil fuel combustion. Within fifteen years after the war ended, humans were putting around 2,500 million tons of carbon into the atmosphere each year. In 1970 this figure increased to over 4,000 million tons, in 1990 to over 6,000, and in 2015 to some 9,500 million tons— about 3,200 times more than in the year 1750 and eight times the total in 1945. By the turn of the twenty-first century, fossil fuels had become responsible for around 85 percent of anthropogenic carbon added to the atmosphere.

McNeill, J. R.. The Great Acceleration (pp. 66-67). Harvard University Press. Kindle Edition.

The concentration of carbon dioxide in the atmosphere grows by roughly half of the amount emitted each year. If the current concentration is 415 ppm, emitting 37 billion tons of CO2 (as we currently do each year) will increase that concentration by about 2 ppm. But the concentration is the result of cumulative emissions, and as we saw earlier, the CO2 we’ve added to the atmosphere doesn’t go away when we stop emitting it. Emissions accumulate in the atmosphere and remain there for centuries as they are slowly absorbed by plants and the oceans. Modest reductions in emissions will only delay, but not prevent, the rise in concentration.

Koonin, Steven E. Unsettled (p. 212). BenBella Books, Inc.. Kindle Edition.