Illustration: Mike Pick
In 2000, as the green shoots of spring cracked through winter’s icy grip on the northern hemisphere, a letter from the Nobel laureate Paul Crutzen and his colleague Eugene Stoermer appeared in the news bulletin of the International Geosphere-Biosphere Programme. In it, Crutzen and Stoermer made the case that the Holocene, the geological epoch that had held sway on Earth for the past 12,000 years, was at an end. In its place, with a start date pegged to the late 18th century commercialization of James Watt’s steam engine, was the Anthropocene, an epoch defined by the influence of humanity’s collective actions. Crutzen was an apt messenger—his Nobel came from work clarifying how the activities of a small number of people had inadvertently initiated a chain reaction that grievously damaged the globe’s protective layer of atmospheric ozone.
The proposal was more widely accepted than a very similar, earlier idea from the journalist Andrew Revkin (he wrote about the “Anthrocene” in 1992), but at the time it still generated considerable controversy. This spring, ten years on, the Anthropocene’s reality is harder to challenge, particularly as manifested through climate change. A surfeit of carbon dioxide is pushing up the planet’s thermostat and initiating a cascade of clear, measurable effects, least of all plants and animals that are waking ever-earlier from winter dormancy. As reported in an upcoming issue of Biology Letters, the latest addition to this list of “early risers” is the Common Brown Butterfly of Australia, which is emerging some 10 days earlier than it did 65 years ago. Nature is adjusting to the Anthropocene. Alas, the same can’t yet be said for world leaders, particularly a small but vocal number of cynical US politicians and corporations.
For humans, adjustments to a warming world can be divided into three categories: mitigation, adaptation, and remediation. The first encompasses things like cutting greenhouse-gas emissions and boosting energy efficiency, and is by far the favorite of modern policy discussions. The second involves actions like building higher seawalls against potential rising oceans, or shifting agricultural practices to align with changing rainfall and temperature. The third option is better known as “geoengineering,” and entails deliberate interventions designed to decrease rising temperatures. Some proposals suggest using atmospheric aerosols or giant orbital mirrors to block sunlight; others plan to capture and sequester carbon by injecting it into the ground or dumping it in the ocean. Though in terms of dollars and cents many geoengineering methods are cheap enough for solitary nations or even private individuals to undertake, few have been thoroughly tested. Fear and uncertainty are the reasons: Geoengineering doesn’t so much adjust to the Anthropocene as kick it into overdrive. All its variations carry major risks and uncertainties.
Consequently, when the Royal Society released an authoritative report on geoengineering in September 2009, it downplayed remediation’s utility in the near-future and pinned hopes on mitigation strategies, like the one expected to emerge from the much-heralded Copenhagen COP15 summit. But COP15 ended in failure: No meaningful restrictions were placed on emissions. Meanwhile, the average temperature inexorably increases, and sensitive geophysical systems show disturbing signs of nonlinear instability. As mitigation strategies fail to gain political traction, geoengineering’s seductive glitter grows.
Now, a study in this week’s PNAS reinforces that even those geoengineering schemes that have a history of scientific testing can still have surprising consequences. Scientists have realized for decades that “fertilizing” desolate regions of the ocean with iron or other nutrients could spawn large blooms of carbon-hungry phytoplankton. In theory, when the phytoplankton died, they’d sink to the ocean floor, carrying their loads of carbon with them. But field tests have shown that, if the blooms form at all, they can fall prey to the local ecosystem; organisms deeper in the water column gobble the phytoplankton and effectively short-circuit any seafloor carbon sequestration. For the new PNAS study, researchers collected water samples from the open ocean and treated them with iron. The iron caused rapid growth of a phytoplankton variety that secretes a potent neurotoxin, domoic acid, which could work its way up the food chain to sicken or kill fish, birds, and people.
The study, while not conclusive, couldn’t have come at a more opportune time. Next week in Asilomar, California, around 150 scientists and policymakers will convene to discuss how geoengineering research should be conducted and regulated. The meeting’s goal is to craft a set of “best practices” for minimizing risks from future testing and deployment of geoengineering proposals. Its location is highly symbolic: Asilomar also hosted a landmark conference in 1975 that ironed out guiding principles for minimizing risks inherent in then-controversial research using recombinant DNA. The resulting guidelines bolstered public support, encouraged more research into recombinant DNA, and helped usher in the modern flowering of biotechnology.
Sensing a potential public-relations victory brewing for geoengineering, opponents have already begun circulating an open letter challenging the conference’s legitimacy and questioning the motives of its organizers. Not coincidentally, one of the organizers of Asilomar is none other than Paul Crutzen, the father of the Anthropocene, who in recent years has emerged as a leading advocate for geoengineering research. It’s also not coincidental that yesterday the Royal Society announced a new initiative to ensure strict governance of geoengineering activities. This is a hedge against the outcome at Asilomar, whatever that may be.
If some consensus is reached by the individuals at Asilomar, then the early spring of 2010 may be seen in hindsight as the time when, for better or worse, humanity decided to truly embrace or reject the Anthropocene—and all its chilling, sublime implications. Amid the inevitable theatrics next week, both sides would do well to pause and remember that.
Lee Billings is a staff editor for Seed. He likes space.
Originally published March 19, 2010