Geoengineering is an explicit recognition that we’ve reached a point where we need to be really worried. People don’t want to recognize that.
As the RV Polarstern crept out of Cape Town Harbor, Victor Smetacek gathered his 49-member crew on deck to watch the lights of the city slowly fade from view. It was January 7, 2009, a cool South African summer evening. And after nearly four years of painstaking preparations, they had finally begun LOHAFEX, the longest and most comprehensive ocean iron fertilization experiment ever attempted.
It hadn’t been easy. Smetacek, a professor of biological oceanography at Germany’s Alfred Wegener Institute, and Wajih Naqvi, a senior scientist at India’s National Institute of Oceanography had published papers in support of the 70-day voyage. They’d trained a joint German-Indian crew and secured the RV Polarstern, a 387-foot German icebreaker operated by the Alfred Wegener Institute. And they’d won approval from both the German and Indian governments.
Finally, the Polarstern was loaded with 20 tons of iron sulphate and headed toward a remote eddy in the Southern Ocean. The crew planned to use the swirling eddy like a giant beaker, pumping iron-rich slurry into the water to fertilize a bloom of plankton and algae. The bloom, it was hypothesized, would absorb atmospheric carbon dioxide as it grew and multiplied. Then, as the organisms died, they’d sink to the bottom of the ocean, permanently locking away their absorbed carbon. The team planned to monitor the bloom over the course of several weeks to determine just how effective it was at absorbing and locking away carbon. But even as the Polarstern left port, opponents were mounting resistance that threatened to stop it in its tracks.
Ocean iron fertilization is one of several techniques that fall under the umbrella term “geoengineering,” a field of study that focuses on limiting the effects of climate change by deliberately manipulating the earth’s climate system. Most geoengineering tactics aim to do this by either making the Earth more reflective to bounce more sunlight back into space, or – like ocean iron fertilization – by removing heat-trapping carbon dioxide from the atmosphere.
Researchers have devised a variety of possible ways to do this, from launching reflective mirrors into space to painting parking lots and roofs white to reflect sunlight. But two tactics – the ocean iron fertilization technique researched by LOHAFEX and albedo modification, which would use atmospheric aerosols to shade the Earth – have attracted the most attention in recent years. Both aim to co-opt or mimic natural processes in an attempt to cool the planet and prevent the worst consequences of climate change. Both are distinctive because of their relatively low up-front costs, their sweeping scope and their possible consequences for the planet. And both have attracted ardent supporters and opponents.
Some scientists see the tactics as potentially vital, if risky, fields of study that we can’t afford not to explore as time ticks away in the fight against climate change. Others see them as irresponsible and potentially disastrous distractions from the all-important work of reducing carbon emissions. The contentious situation has made research difficult; with funding from U.S. agencies scarce, many scientists have been forced to scale back their work.
Among those scientists is Phil Rasch, chief scientist for climate science at Pacific Northwest National Laboratory. An expert in climate modeling and atmospheric chemistry, he has found it difficult to get funding for his research into atmospheric aerosols. He believes that much of the controversy stems from simple reluctance to acknowledge the seriousness of climate change – and the role of humans in causing it. He argues that it may not be wise to let new ideas languish as changes to the Earth’s climate accelerate.
“We would all like to believe that we’re not harming the planet,” he said. “And any time you consider something like geoengineering, it’s an explicit recognition that we’ve reached a point where we need to be really worried,” he said. “People don’t want to recognize that.”
Reticence about geoengineering research has led to painfully slow progress for some ideas. Ocean iron fertilization, for example, was initially proposed back in the 1980s by the late oceanographer John Martin. He hypothesized that iron-rich dust blowing off the coasts of Africa and Australia caused the last ice age by fertilizing massive plankton and algae blooms in the ocean. He believed that it might be possible to use artificial iron fertilization to slow or even reverse climate change caused by carbon dioxide emissions. And he launched his idea with what’s still perhaps the most quotable quote in climate science: “Give me half a tanker of iron and I’ll give you an ice age.”
But as LOHAFEX set sail two decades later, the science was still poorly understood. Earlier experiments had shown that iron fertilization does indeed cause massive, carbon-absorbing plankton blooms, but whether those blooms were effective at long-term sequestration of carbon was unclear. And a rush of commercial interest had damaged the credibility of the field, scaring off many scientists and making the LOHAFEX experiment an uphill battle from the beginning.
“Iron fertilization got this reputation as a mad scientist idea,” Smetacek said. “It had attracted the interest of venture capitalists who wanted to use it to sell carbon credits, and that scared the daylights out of many scientists.”
The controversy caught up with the crew of the Polarstern seven days into LOHAFEX, when the German government ordered the crew to halt its work. Though they had previously approved the experiment, protests from a Canadian environmental group and uncertainty over whether the experiment violated a vaguely worded United Nations resolution caused regulators to walk back their support. The massive ship and her crew were in limbo for six days. They used the time as productively as they could, but it looked as if they might have to abandon the experiment and return to port.
Finally, on the night of January 26, the Polarstern received a phone call with good news: Germany’s Federal Ministry of Research had cleared the ship for a scaled-down experiment, authorizing the release of six tons of iron. Once the cheering subsided, the crew got to work immediately, pumping the iron solution through a hose into the ship’s propeller wash.
The team monitored the fertilized eddy for 39 days. Ultimately, they found that the plankton bloom they caused wasn’t very efficient at locking away carbon in the deep ocean. Much of it was eaten by scavengers, recycling the captured carbon back into the atmosphere before it reached the ocean floor.
Partly as a result of the LOHAFEX study, most scientists now agree that the risk of disrupting the ocean’s ecosystems with iron fertilization far outweighs what would likely be a small reduction in atmospheric carbon dioxide. A 2015 National Academy of Sciences report that evaluates several possible geoengineering technologies recommends curtailing further ocean iron fertilization research and focusing resources on other, more promising areas of study.
But LOHAFEX shows that even when research doesn’t directly result in a viable technology, it can move the science forward, answering questions and informing future research. Scientists like Rasch believe that we’ll need to pursue that research more decisively to determine whether other, more promising new ideas could help us manage climate change and its consequences.
“We don’t have a lot of time to mess around,” he said. “Because some of the changes we’re anticipating will at some point become irreversible.”