Humanity’s Last Stand How We Can Stop Climate Change before It Kills Us


IT’S THE MOST BEAUTIFUL day of the year. Officially.

I’ve just come from my monthly gig at the Channel 8 studios, where Shaun the meteorologist has proclaimed it sunny, seventy degrees, and calm in the Great Plains. Perfect spring weather.

Meanwhile, in the parking lot of the fitness club that is my next stop sits a Chevy Tahoe, tinted windows rolled up and engine running. In any other country this “car” would be classified a bus. Or maybe a tank. And yet, its ninety-five cubic feet contain only a petite, pony-tailed driver who checks her phone as the V8, 16-mpg engine, running completely unnecessary air conditioning, pumps CO2 into the air—on a perfect spring day.

And it’s not just her. As I stroll through the lot I spot two more cars with engines idling. That’s a sixth of all the parked vehicles. With gasoline at $1.92 a gallon, this doesn’t even qualify as conspicuous consumption.

“This is why we’re all gonna die,” I think to myself, clenching my teeth. Then, like most everyone else, I get back to my routine: exercise, go back to my job, head home, make dinner, watch TV. Toss a child’s bodyweight in carbon dioxide into the atmosphere.

Climate change is happening now. With few exceptions, glaciers are in retreat. Sea ice is thinning. Two new studies converge on a single, scary, all-too-possible consequence of humanity’s profligate use of fossil fuels: the break-up of Antarctic ice within this century. Yet, as we’ll see, Antarctica may be just the place for us to push back against meltdown.

Noting the “exponential growth of fossil fuel use” in the past century, a peer-reviewed paper by former NASA climatologist James Hansen and a dozen other experts says industrialization has overwhelmed natural climate systems, tipping our planet into the “Hyper-Anthropocene”—an era in which feedback loops lead to rapid, radical climate change. The loss of polar ice, the Atmospheric Chemistry and Physics paper predicts, will flood many of the world’s coastline cities by the end of the century.

The Hansen et al. paper goes well beyond the forecast of the Intergovernmental Panel on Climate Change (IPCC). It also has numerous credible critics, including climate scientist Michael Mann of Penn State University, who told the Guardian newspaper, “I’m unconvinced that we could see melting rates over the next few decades anywhere near his exponential predictions.”

So, maybe we could set Hansen’s paper aside and get back to worrying about terrorism, the economy, inequality, and all the other immediate yet ultimately less consequential concerns we face. Except that no responsible critic thinks Hansen’s a crank, and two other climate scientists have come to a conclusion similar to his. Geoscientist Robert DeConto and paleoclimatologist David Pollard have spent decades testing and refining computer climate models. (They test them by simulating a past period whose climate is well known, and then comparing the simulation with the record.)

If anything, their paper is even more ominous than Hansen’s. Published this March in the journal Nature, it notes that during past interglacial periods, when the levels of atmospheric CO2 were about the same as they are today, 400 ppm, sea levels swelled to nearly 100 feet higher than today’s level. During the most recent interglacial period, with less CO₂ in the air, sea level crested at thirty feet above today’s level. The difference? Timing of Antarctic ice melt.

DeConto and Pollard’s model suggests that the slow but inexorable warming of ocean currents threatens to destabilize the West Antarctic Ice Sheet, a vast reservoir of water. By undermining the fringe ice, warm currents may expose inner ice cliffs to warm summer air, creating fissures of meltwater that cleave them. Such processes have been observed in the collapse of smaller ice sheets and are gnawing away at Greenland’s ice reserves.

The computer model newly refined by DeConto and Pollard now accurately postdicts the last interglacial period, and when the scientists swing it around to peer into the future, it produces a dismal picture. At worst, it shows the oceans rearing up five or six feet this century to inundate New York and other great cities of the world. Superstorms like Sandy, which flooded New York and devastated much of coastal New Jersey in 2012, could triple or quadruple that rise on any given day.

DeConto and Pollard disclose in their paper that the model is imperfect. It lacks, for example, a two-way junction between ocean currents and the ice sheets, which reduce the ocean’s salinity as they melt. But the model is good enough to reproduce some known results, and in any case the long-term consequences of continuing to burn fossil fuels are clear. All climatic records and models of the future agree: if we sail past 2°C temperature rise, the question isn’t whether the ice sheets dissolve but when.

Worse yet, DeConto and Pollard’s model indicates that once the ice goes, it won’t be back for thousands of years. Warm the oceans, and you cannot cool them in any less time.

Does this mean we’re doomed? Thirty-seven years after the first climate conference, the one that led to the formation of the IPCC, greenhouse gas emissions continue to rise. Led by oil companies, an array of corporations backs an effective disinformation campaign about climate change. The world’s political leaders continue to meet and make empty promises. And even those most worried about the climate tend to do little about it.

In some ways, this is easy to understand. Climate change is the ultimate tragedy of the commons. (Medieval sheepherders stripped the common grazing land bare, thereby starving their flocks, even though it would have been in their collective interest to restrain consumption.) Any sacrifice we make for the sake of climate stability has no observable local effect and can easily be offset by someone else’s irresponsibility. Any joint action humanity takes to curb greenhouse gas emissions will only have benefits in the hazy future. If psychologists were trying to devise the most ineffective strategy for the human species they could hardly come up with a worse scenario. We are by nature invested in short-term, local advantage.

So, should we just fiddle till the floods roll in? Of course not. Climate scientists, including DeConto and Pollard, generally agree that we aren’t yet past the point of no return. True, average global temperatures have climbed halfway to the critical 2°C mark, and 2015 was the hottest year on record. It’s also true that April set a new heat record for itself.

Yet, there are heartening changes afoot. Globally, after climbing at a 4 percent annual clip, CO2 emissions growth has slowed to a crawl. It all but stalled in 2014. Since 2000, twenty-one advanced nations have reduced their greenhouse gas emissions while growing their economies.

Even more notable, the United States has been one of them. Our CO2 output began dropping after 2005 and fell 6 percent from 2010 to 2012 (largely because of a switch from coal to natural gas, along with increasing transportation efficiencies). It must be noted that methane leakage at fracking sites and a subsequent plunge in gasoline prices may threaten that trend, but the principle has been proven: even Americans, the world’s largest per capita greenhouse gas polluters, can cut back.

Moreover, Americans are finally looking past the propaganda and accepting the reality of climate change. A Gallup poll this spring showed that concern about climate change has reached an eight-year high of 64 percent.

So, while it’s true that climate remains a lot like the weather—everyone talks about it, but no one does anything—that may not be true for much longer. Social psychology has its tipping points, and if Big Oil borrowed Big Tobacco’s playbook for its disinformation campaign, the long-term results may disappoint them. After happily puffing away for decades, Americans have roundly rejected cigarettes. The remaining 16.8 percent who smoke are often treated as social pariahs.

Yet, for all that the question remains, what to do? Humanity is still pumping an extra thirty gigatons of CO2 a year into the air. Population growth alone means that greenhouse gas emissions will rise. Though China’s economic growth has slowed, India’s economy is heating up—and with it, emissions. Other nations aspiring to a decent standard of living will want to follow suit.

Can they do it, and can we continue to grow wealthier, while cutting carbon emissions? Technology will play a key role. But even changing out gas engines for electric motors and swapping coal-fired plants for geothermal, nuclear, wind, solar or some future renewable won’t be enough. The 2014 IPCC report recognizes that to avoid swamping island nations, acidifying the oceans, and bringing on calamitous droughts, we have to do what political campaigns do. We have to go negative.

Negative carbon emissions means finding ways to pull carbon out of the air and tuck it safely away. So great is the importance of putting the carbon genie back in the bottle that virtually all of the finalists competing for Richard Branson’s $25 million Virgin Earth prize have carbon capture at the heart of their proposals. Despite some ingenious technologies in the running, the selection committee has yet to pick a winner.

Perhaps this is because there’s a price to pay for decarbonizing. The double bonds that clasp carbon to oxygen are tough to break. Writing for Scientific American, Sandia National Laboratories engineer James E. Miller notes, “If energy from coal were applied to drive the decomposition reaction, more CO2 would be released than consumed, because no process is perfectly efficient.”

Fortunately, Earth has a free, nonpolluting source of energy: the Sun. What’s more, we have an ancient technology that exploits this free energy to capture megatons of carbon dioxide. It’s called a forest.


Photo © Sleiselei |

Photo © Sleiselei |


HAVE YOU EVER wondered how a tree can grow so big without creating a bowl at its base? It builds itself out of atmospheric carbon. One simple, risk-free way we can reverse some of the carbon pollution we’ve created, internationally recognized scientist Sally Benson points out, is to restore the vast tracts of forest we’ve destroyed. Benson holds a triple appointment at Stanford University, where among other things she heads a lab dedicated to investigating carbon storage deep underground. A hydrological engineer by training, she was a co-leader of the 2005 IPCC report on carbon capture’s potential to slow climate change.

Her lab focuses on another relatively low-risk, though not necessarily inexpensive, way to capture and store CO2: by running the exhaust from a coal- or gas-burning power plant through a chemical bath that extracts CO2, and then pumping the gas deep underground for permanent storage. By exploiting CO2 as a geothermal medium for cogeneration, it may even become possible for it to pay for itself in some locations.

Benson says her research shows that where geologic conditions are favorable, carbon capture and storage works. For well-located power plants, carbon sequestration could be 90 percent effective, but not all plants can be retrofitted or connected to suitable storage sites. Taking that into account, Benson says, “Carbon dioxide storage is a 10 to 15 percent solution,” adding, “it’s not a silver bullet.” She also notes that if we cut vehicle emissions by switching to electric engines, we’ll need a lot more power plants. Clearly, mitigation efforts have got to go further.

Fortunately, in addition to the forests, we have one other great natural ally: algae. An ancient and wildly diverse photosynthesizing organism, algae range from microscopic diatoms to giant kelp.

Richard Sayre heads a team at the New Mexico Consortium (a nonprofit research wing of three area universities) that investigates the uses of algae. At present, algal research focuses on the use of microalgae to generate biofuels—a renewable that can substitute for fossil fuels. However, Sayre said in an email interview, “if emissions continue to grow there will be a tipping point when atmospheric carbon remediation will need to be considered.”

Miscoscopic diatoms (CC By-SA 3.0, Modified)

Miscoscopic diatoms (CC By-SA 3.0, Modified)

In that case, land-based microalgae could prove to be effective carbon sinks. Sayre foresees this working in tandem with biofuel production, which would provide a financial incentive to use land for algae cultivation. In principle, he says, algae could both power the nation’s vehicle fleet and offset its emissions.

“A hectare [~2.5 acres] of algae could capture the carbon generated from combusting thirty-four gallons of gasoline per day,” Sayre says. “So 11.3 million hectares, or 29 million acres, of algae would need to be grown to capture all of this carbon as algae oil to bury under optimal growth conditions.”

Noting that 29 million acres is about the size of Pennsylvania and that several caveats get in the way of optimal conditions, Sayre acknowledges that the land-based algae sink is unlikely to solve our greenhouse gas challenge. “But it could be part of the solution along with increases in car fuel efficiency and switching to renewable electric power to drive cars.”

There is, however, another place where algae grow: the oceans. Covering 70 percent of the Earth’s surface, the oceans offer the largest solar-powered carbon sink in the world. To switch it on, all we have to do is feed it rust. Iron is the one missing nutrient for much of the algae in the wild.

But, as always, there’s a hitch. Feeding ocean algae carries a known risk. As algae die, they suck oxygen out of the water, choking fish and other organisms. In the Gulf of Mexico, where algae feast on agricultural fertilizer runoff streaming from the Mississippi, a great dead zone has appeared.

There are also unknown risks. For one, cultivating ocean algae may prove ineffective as a carbon sink. Benson points out that microalgae sit at the bottom of a complex food chain, making the ultimate destination of any CO2 they absorb hard to determine. For example, what if a bird eats the fish that ate the shrimp that ate the algae? Once it defecates, we’re back where we started.

Stimulating algae growth may also disrupt the food chain. Studies have shown that the ocean’s food web is highly nonlinear, meaning that perturbations can have outsize effects all up and down the line. For Sayre, it’s case closed: “Too risky and likely to disrupt ecosystems in the ocean.”

But scientists who are taking a second look have their reasons. First, unless we hold the line on climate change, the algal food chain will be disrupted anyway. A team led by MIT scientists has found that increasing acidification will lead to wild gyrations in the world’s algal populations. “I was actually quite shocked by the results,” said lead researcher Stephanie Dutkiewicz in an MIT release. “[T]here might be some quite traumatic changes. … A whole rearrangement of the communities means something to both the food web further up, but also for things like cycling of carbon.”

Standing pat appears no less risky than plunging in. What’s more, intervention may be easier to manage than reaction. Proactive use of bioengineering may help us limit the risks. Ted Reid is a biochemist and big thinker at Texas Tech University. “I think that algae would be a great target for genetic engineering,” he says. Among the possibilities: genes to curb undesirable effects, to ward off unwanted predators, and even, conceivably, to insert a fail-safe genetic switch that would allow us to kill off algae should an unforeseen dire consequence arise. Such a switch could be inserted with a genetic combination lock that would require a highly unlikely series of multiple mutations to undo.

Which bring us to what is perhaps the biggest and best—or worst—idea of all: to revive the kelp forests around Antarctica. David Harwood is a geologist with a specialty in marine ecology and the geologic records it leaves. Having led the $30 million ANDRILL project to recover deep ice and sediment cores from Antarctica, Harwood says he’s learned something amazing from that research.

When the climate was warmer, Antarctica was belted by a dense kelp forest, much like the one that lies off the coast of California today. “We’d previously recorded algae in the [shoreline] benthic zone,” he said in an interview, “but now we’re learning that it extended out four kilometers.” Given that Antarctica is larger than the United States, a 4-km ring of kelp surrounding the southern continent would be, in today’s political parlance, huge.

Much like a land-based forest, the kelp provide surface and structure for whole ecosystems. The Antarctic kelp has some distinguishing features.

When conditions are favorable, it harbors massive amounts of fast-breeding diatoms—a hard-cased variety of plankton that are excellent carbon packers. The diatoms in turn provide food for the most abundant animal in the southern oceans—krill. A shrimp-like amphipod, krill are tiny creatures that provide the staple for everything from penguins to humpback whales. But when times are good, the ANDRILL cores show, krill are so numerous that most live out their lives munching on diatoms.

That’s the key to CO2 removal, Harwood says. “Their fecal pellets are full of carbon, and they just sink to the bottom and lock it up for at least a thousand years.”

Right now, it’s still too cold and icy for much algal action in the antipodes. But that will change, and if we prepare carefully, perhaps we can nurture optimal conditions for the kelp forests to spring back to life.

We can, for example, jump-start them with bioengineering. “If temperature is a problem,” Reid says, “research could be carried out to determine temperature-sensitive genes.” Genes allowing for the growth at a lower temperature could be promoted in the target region. We’d also have to nurture the algal ecosystem with iron. Once revived, the system would be largely self-regulating. According to Harwood, the core records show that as Antarctic kelp forests suck CO2 out of the atmosphere during warm periods, the temperature begins to drop, bringing back sea ice and massive ice shelves on the continent.

“The floating ice grinds away the community of algae,” he says. What’s more, mounting ice shelves reduce the sunlight available to diatoms for photosynthesis, so the CO2 sequestration slows until a new equilibrium is reached.

If Harwood is right, all this will happen anyway. Earth has righted the ship of life before, but, unaided, such change is unlikely to come in time to save human civilization from our folly. According to the earlier-cited studies, as well as other research on impending drought, a single human lifetime is all that remains before catastrophic effects set in.

The normal scale of climate change is thousands of years. It appears, then, that in addition to replacing fossil fuels, we must boldly strive one way or another to put carbon back where we found it. If that sounds too meddling, try to reframe. Don’t think of it as scientific arrogance; think of it as acting to get back in harmony with nature.