How Pumping Gas Today Will Impact Humans in 100,000 Years

  While much of the world has been bickering over whether climate change is real or not, climate scientists have been going about their research as usual. But what they have been discovering is revolutionary. Not only is human-driven climate change real; it's even more serious than we thought.

Until now, most views of future temperature trends have been limited to this century, as if 2100 AD marked the outer edge of a world beyond which we dare not probe. The latest research pushes past that arbitrary temporal boundary to ask "what happens next?" According to investigators such as David Archer, an oceanographer and climate modeler at the University of Chicago, the heat-trapping gases that we release now will linger for tens of thousands of years, long enough to interfere with future ice ages. From that perspective, global warming is essentially forever--at least in human terms.

How can this be? Earlier studies have suggested that we're tracing a trail of carbon footprints just a few centuries long, but more sophisticated models and analyses now clearly show otherwise. The logic behind this is surprisingly simple, amounting to common sense combined with a truly long-term perspective. Carbon dioxide doesn't just disappear when it leaves our tailpipes and smokestacks--it has to go somewhere. And people like Archer follow the invisible tracks of that carbon to find out where it eventually goes.

"The main destination is the oceans," he explained over the phone. "Carbon dioxide dissolves in seawater, and that's where most of it will go within the next several millennia." Unfortunately, when CO2 dissolves into seawater it forms carbonic acid, thereby threatening everything with acid-soluble hard parts, from clams to crabs to corals. Such ocean acidification is already happening, and it will grow progressively worse the more CO2 we pump into the air.

"The oceans can only absorb so much carbon dioxide, though, so roughly a fifth of our emissions will be marooned in the atmosphere. It will then take many thousands of years for chemical reactions with rocks and sediments to scrub the rest of it away."

The work of Archer and others show that we have an important choice to make during this century. If we switch to carbon-free fuels quickly, our greenhouse gas emissions will keep the world slightly warmer than today for as long as 100,000 years. As unsettling as that may be, the alternative is even more severe. If we burn all remaining fossil fuels, including our huge coal reserves, the warming will be five to ten times more extreme and last five to ten times longer.

In short, we've become a shockingly powerful force of nature. I liken this revelation to the first NASA photos of Earth, from which we learned that we ride a delicate blue bubble through deep space. This equally transformative view of our place in deep time shows that we are also incredibly important. We're now so numerous and our technology so powerful that the effects of our collective actions in coming decades will echo on down through the ages.

And there's more. Near-term global warming will be followed by entirely different environmental challenges. "After our carbon emissions peak and begin to fall back down," Archer continued, "temperatures will also peak and begin to drop, first rapidly as the oceans do their work, and then more slowly as the rocks finish the job." Most of the recovery from our carbon legacy will therefore involve global cooling, albeit from temperatures higher than those of today. And that will bring reversed versions of environmental problems that worry us here and now, including sea level retreat, re-shuffling of rainfall patterns, and eventual re-freezing of formerly ice-free regions.

An ice-free Arctic may seem unthinkable to us now, but by 100,000 AD it will have become normal, even ancient. When climates once again begin to resemble those of today, the re-freezing of the open polar sea may be equally unsettling to our distant descendants who will have come to depend on it. As far-sighted elders notice the first skim of ice forming along some shoreline, perhaps they'll whisper, "I don't remember seeing that before. If this continues, the whole place might freeze over--what a disaster!"

Fortunately, such dark views of our deep future also reveal a few bright spots. For one thing, we've stopped the next ice age. Natural cycles were scheduled to launch it around 50,000 AD, but our lingering fumes will keep the world just warm enough then to save the northern halves of North America and Europe from being bulldozed by mile-thick slabs of ice. Feel better now?

More importantly, we still have time to decide which path we're going to take. If we switch soon to carbon-free energy sources, most cultures, habitats, and species may manage to adapt to the relatively moderate changes that will result over the next 100,000 years. But an uncontrolled carbon-burning spree will melt all polar ice, hoist sea levels by hundreds of feet, and stretch massive warming-then-cooling disruptions over the next half a million years or more.

What's at stake in this big picture? Admittedly, climates and sea levels will eventually recover in either scenario, and Homo sapiens may be resourceful enough to survive somehow as a species. But the free migration that helped animals and plants to adjust to natural climatic shifts of the past will not be so freely available with our settlements, roads, and farms in the way. And if we take the extreme path, there may be no refuge at all for polar bears or other cold-loving creatures, not to mention marine life trapped in the acidifying oceans.

Global warming will last a long time in comparison to the lifespan of a short-sighted human. But extinction is truly forever.

Curt Stager is an ecologist, paleoclimatologist, and science journalist with a Ph.D. in biology and geology from Duke University. His new book is DEEP FUTURE: The Next 100,000 Years of Life on Earth (St. Martin's Press, March 2011).

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7 Comments

  • C7

    Earth and humanity will be extinct in billion years from now as Sun turns Red Giant phase and swallows it, probably yet presumably.

  • Michael Brown

    Pumping gas? Are you kidding me?

    Once again more sheep are led to the slaughter by this one-sided "scientific" malarkey. Humans are not impacting climate change anymore than dinosour farts did thousands of years ago. If half the lemmings would stop following long enough to apply a little common sense, then these "scientists" would have no audience.

    Look at the climate shifts the earth has experienced in the past several thousand years. Shifts much more cataclismic than the fractions of a degree we're talking about today. Man was not even industrialized when those shifts took place. Now if that type of climate activity can happen absent of mans influence, then what makes people think todays (much smaller scale) changes were caused by, or can even be reversed by man?

    Lighten up people.

  • bbaker6212

    Lots of long term thinking about the contributing factors but nothing about counter-acting or side-effects. Surely over thousands of years a higher quantity of of carbon dioxide in the atmosphere will create more plant growth both on land and in the sea, which will obviously create more oxygen. It's known that in the distant past there was more carbon dioxide, plant life, and larger animals. Where is the research/comments about this effect?

  • Andrew Krause

    "Not only is human-driven climate change real; it's even more serious than we thought." Or so say the people trying to sell books.The very reason that there is bickering is because the science supporting anthropogenic climate change (ACC) is deeply flawed and has been unable to produce near-term forecasts of climate trends that are any bit reliable. (These should be the easiest forecasts to make, too.) Not to mention the climate-gate email scandal wherein top scientists who are pushing ACC were proven to have violated scientific principles and public trust by altering and selectively sampling data from disparate sources.

    Let's keep this in perspective. The overall change in atmospheric composition as caused by humans is measured in parts-per-million. We've barely nudged the needle with more than 200 years of carbon emissions. Next consider that carbon dioxide is part of the ecosystem, and supports the majority of life on the planet. And finally consider that the total of annual human carbon emissions are marginal compared to natural sources. One volcanic eruption alone is worth several years of human activity.

    There cannot be a rational discussion about the impact of human activity on the health and well being of the biosphere so long as people push the myth that carbon dioxide is the greatest threat to it.

  • WMD

    Curt, Once again you people base an urgent message on assumptions that your guys are correct. The same kind of guys that spin their reports for more government handouts (researcher’s welfare), the same kind of guys that makes 100’s of millions of dollars on books and speaking engagements, the same kind of guys that want silly carbon tax to line their pockets with money, the same kind of guys that need power and control over others, the same kind of guys that cover-up changes in climate models to meet their political needs.

    Bottom-line... you have told me nothing!

    What we need are honest scientists that can tell us the truth. Until then keep trying to scare the world for a few more bucks.

    WMD

  • J Matt

    Mr. Stager is a good writer, this piece flows well and is very understandable. I have no doubt that he is also a good scientist because his area of study is one of the most complex that we have in science today. I completely agree that human beings need to adhere to a more sustainable way of existing here on Earth. However the leap from how carbonic acid is made to dissolving the worlds shellfish population is a bit much. It is, easy enough for his publisher to understand, especially based on the market they are tapping. Predicting the pH of our oceans in 100,000 years is just a little ways beyond that.

    Three things come to mind: 1) Mankind's existence has been threatened many times and we are possibly in a more precarious position today then we know, for reasons we are not even aware of. 2) The Human ego is such that we all think, as Caspar Weinberger did that, " I am in control here" when quite the opposite is often the case. And 3) For all of the problems we have faced somehow we have survived and prospered here on earth. The paranoid have many sources of fear to draw from but I'll put my money on ingenuity and survival. I love science but I loose a little respect for those cashing in on hot button theories these days.

  • Bahbahcha

    Incredible, everyone commenting here probably thinks we didn't go the to moon either. I'm so bored with people arguing with scientific facts all day, forget writing anything lengthy I have done that plenty I am done wasting my time on the minds of those bought-out by big oil.