Notes from a Warming World | Autumn 2012

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Iron Sink

It appears that dumping iron in the sea can help suck carbon out of the air and bury it underwater, like, forever.

New research by a team of international researchers published in the journal Nature shows that spreading iron dust in the sea causes a growth spurt in a certain type of carbon-sucking algae that sink as they die, taking the carbon they have absorbed from the atmosphere with them to the bottom of the ocean floor. The scientists suggest their findings could help control climate change.

For their study, the team dumped seven tons of iron sulfate into the Antarctic Ocean in 2004. At least half of the heat-trapping carbon captured by the resulting bloom of diatoms, a type of algae, sank below 3,300 ft, leading the scientists to conclude that “iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments.”

The process of adding iron in the sea, called “ocean fertilization,” is one of several geo-engineering techniques for slowing climate change that scientists have been researching. There had been doubts about whether the carbon captured by ocean fertilization would stay in the upper ocean layers, where it could mix back into the air. The latest study is the first convincing evidence that carbon absorbed by algae during photosynthesis can sink to the ocean bed.

photo of a microscopic organismphoto Antonio GuillénSprinkling iron dust in the sea causes a growth spurt in a certain type of carbon-sucking algae.

The research, however, failed to answer questions about possible damage to marine life from artificially generated algal blooms. Some types of diatoms known as red tides, for example, can be harmful to underwater ecosystems. When these algae decay in large quantities, they absorb oxygen and release nitrogen into the water, killing off fish, marine mammals, and birds. Red tides can also trigger skin and respiratory problems in humans.

Large-scale experiments with ocean fertilization are currently banned by the London Convention, which restricts dumping at sea. Victor Smetacek, lead author of the Nature study, says that is “a crying shame” because it blocks crucial research that would help us understand “what might happen to species composition” if we were to continuously add iron to the sea.

Fair enough. Though that experiment sort of sounds like adding straws to a bale to see which one will break the camel’s back.

He Would Say That

Ocean fertilization is just the kind of thing that would appeal to ExxonMobil CEO Rex Tillerson, who believes we should focus on engineering fixes to cope with climate change rather than try to reduce fossil fuel use.

“Changes to weather patterns that move crop production areas around – we’ll adapt to that. It’s an engineering problem and it has engineering solutions,” Tillerson said during a recent presentation to the Council on Foreign Relations.

In his speech Tillerson blamed a public that’s “illiterate” in science and math, a “lazy” press, and advocacy groups that “manufacture fear” for misconceptions about the impacts of oil and gas drilling and use. Compared to his predecessor, Lee Raymond, Tillerson is something of a moderate, having publicly acknowledged the fact of anthropogenic climate change.

Tillerson said humanity should focus its efforts on adapting to the effects of a warmer earth. “We have spent our entire existence adapting, OK? So we will adapt to this,” he said. Tillerson evidently believes that adaptation and mitigation are still either/or choices we have the leisure to make. At this point, many climatologists disagree. We need to prepare for the worst and, at the same time, do our best to avoid the most damaging climate dislocations. As Angela Anderson, climate and energy program director at the Union of Concerned Scientists, puts it: “There are effects of climate change that are difficult, if not impossible, to adapt to.”

Depends How You Say It

The ExxonMobil chief’s views are in keeping with how many self-described conservatives approach climate change science. A study by researchers at Yale found that people with generally conservative worldviews often dismiss climate science because they sense that accepting it would lead to restraints on commerce, something they value. But if they are told that there is a technological fix to global warming like geo-engineering, then they are more likely to accept the scientific consensus on human-driven climate change.

So environmentalists could shift the climate change debate in the US by reframing it as a technological issue rather than a regulatory one. The only problem: That could leave us stuck pouring iron into the ocean for the rest of time.

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