Scientists Wary of Iron as Proposed Climate Fix Two companies say the best way to slow global warming is to dump iron into the oceans. The iron would trigger blooms of tiny plants that suck carbon dioxide out of the atmosphere and then keep it trapped deep in the ocean. But scientists are wary.

Scientists Wary of Iron as Proposed Climate Fix

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From NPR news, this is ALL THINGS CONSIDERED. I'm Melissa Block.

It's time now for Climate Connections, our yearlong series with National Geographic. Today, we explore whether global warming could be slowed by dumping iron into the ocean.

Sometime next year, a private company wants to sail into the Pacific Ocean and spray seawater laden with particles of iron into the sea. The idea is to fertilize the growth of plankton, tiny marine plants that can suck carbon dioxide out of the atmosphere, where the gas is warming the planet. The company backing the voyage is called Planktos. It promises to offer a low-cost way to cancel out the carbon dioxide produced by burning fossil fuels.

But some scientists have serious doubts, as NPR's Christopher Joyce reports.

CHRISTOPHER JOYCE: Woods Hole is a pint-sized village on the Atlantic Ocean served by a ferry and a single road. Swing a cat here and you'll hit a boat or an oceanographer. Nearly 100 ocean scientists recently came to the Woods Hole Oceanographic Institute to talk about fertilizing the ocean with iron. These are people who have either worked on or reviewed the 11 iron in the ocean experiments so far. Some of them say it could be a good idea, others say probably not.

That made pour some testy exchanges among people who've worked together for years, like this one between skeptic John Cullen of Dalhousie University in Canada and Andy Watson at the University of East Anglia in Great Britain.

Dr. JOHN CULLEN (Oceanography, Dalhousie University): We should say, don't even take that first step until we've had prudent consideration of the likely consequences.

Professor ANDY WATSON (Environmental Sciences, University of East Anglia): But the point is that this is an incremental thing. You're don't - if you start to say that it's going wrong, then you can roll back.

Dr. CULLEN: Good argument, Andy.

Prof. WATSON: Taking the first step is not getting to the final.

Dr. CULLEN: And the point of my talk, which is open for debate, the scientific parts is there are consequences that we couldn't see. So it could be going wrong and we wouldn't know it.

JOYCE: Cullen says adding iron to the ocean could create subtle changes in plankton species or the ocean's chemistry that might go unnoticed and eventually alter the world's oceans. And Cullen says there'd be no way to place blame if something goes wrong, like massive fish kill for instance.

Dr. CULLEN: Now, if it happens in 2017, 2018 and 2019, are we going to know whether that was something that may have happened anyway or it happened because people have been fertilizing the North Pacific for 10 years? I don't think we'd ever be able to sort that out.

JOYCE: Here's another question. The plankton absorb carbon dioxide then get eaten or die. Supposedly, the carbon they absorb sinks, but how far and for how long, no one knows for sure. And these iron-eating plankton can create some nasty byproducts like nitrous oxide, a greenhouse gas even more potent than carbon dioxide. Most scientists at Woods Hole say they want more experiments, but many don't want Planktos and its flamboyant director to do them. Funding from the federal government for experiments has mostly dried up for lack of interests, so who will pay?

Well, there's a new well-financed company in the game now called Climos. Its scientific director is a respected oceanographer who's well known to experts in this arcane field, Margaret Leinen.

Dr. MARGARET LEINEN (Scientific Director, Climos): If this is a way of sequestering carbon, there is very active and vigorous market for selling the credit for that carbon sequestration. And that's the business opportunity.

JOYCE: Carbon credits are created when someone pulls carbon out of the atmosphere and stores or sequesters it. Every ton of sequestered carbon can generate a credit worth about $10 on the carbon market. Companies that want to negate or offset their own CO2 emissions then buy these credits. Leinen says the experiments so far suggest that ocean fertilization may work and poses no big threat. Climos is working with a carbon-marketing company, EcoSecurities, to sell carbon credits from ocean fertilization. Climos is also planning a big experiment, but won't say when, and promises to work with the Environmental Protection Agency to make sure it's safe.

Among those who are guardedly optimistic is Kenneth Coale. He runs the Moss Landing Marine Laboratories in California. He says going slow may no longer be an option.

Dr. KENNETH COALE (Director, Moss Landing Marine Laboratories): I think the science may say that we need to look at this further. And I think there's others in here, at this conference, who would say if it makes money, let's do it now.

JOYCE: Coale says that may push researchers out of their comfort zone, but adds that the risks of fertilization may be outweighed by the looming and undisputed danger posed by global warming.

Dr. COALE: There are many of us who believe that the oceans are somehow sacred and should not be manipulated. But when you take, you know, a higher altitude perspective, we've already manipulated the oceans massively and drastically.

JOYCE: The international body that regulates pollution in the oceans recently asked scientists to resolve the safety question once and for all, which makes it likely that experiments will continue, perhaps paid for this time by carbon entrepreneurs.

Christopher Joyce, NPR News.

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