Scientists will change the ocean so that it absorbs more carbon dioxide

Scientists will change the ocean so that it absorbs more carbon dioxide

TO Alec Luhn

Scientists plan to seed part of the Pacific Ocean with iron trigger a bloom of phytoplankton on the surface that will hopefully absorb carbon dioxide from the air, reviving field trials of a geoengineering technology that has been taboo for more than a decade.

On September 9, 23 scientists from Exploring Ocean Iron Solutions (ExOIS), a non-profit consortium, presented program V Boundaries in climate evaluate iron fertilizer. Researchers want to more accurately determine the amount of CO₂ The technology could isolate the deep sea and what impact it could have on marine ecosystems. They hope to begin testing in a 10,000-square-kilometer area of ​​the northeastern Pacific Ocean as early as 2026, says consortium member Ken Buesseler of the Woods Hole Oceanographic Institution.

The Intergovernmental Panel on Climate Change says the world will likely need to remove billions of tons of CO2 from the atmosphere.₂ limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit), and Buesseler says fertilization could be “one piece of that puzzle.” The ocean already holds far more carbon than Earth’s plants, crops, and soils, he says, and it has the potential to hold far more. Spreading iron, he adds, could “speed up” the natural biological carbon pump, promoting greater phytoplankton growth.

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During photosynthesis, phytoplankton consumes CO₂sunlight and nutrients, including iron. But in many parts of the ocean, the element is rare. If some of it gets to these areas on wind-blown dust or volcanic ash—or by a ship deliberately pumping out a solution of iron sulfate—massive numbers of microscopic organisms can grow and reproduce rapidly. When these creatures die or are eaten and excreted by larger creatures, some of the carbon they absorbed sinks into deep, slow-moving waters as “marine snow,” trapping the carbon outside the atmosphere for decades or centuries.

ExOIS is trying to raise $160 million for the entire program. To start, scientists have received $2 million. grant from the National Oceanic and Atmospheric Administration for computer modeling, and they are in talks with potential donors such as the Ocean Sustainability and Climate Alliance, a philanthropic coalition funded by billionaire Michael Bloomberg and others.

ExOIS plans to apply to the U.S. Environmental Protection Agency for permission to conduct the tests under the London Protocol, which in 2013 established an international ban on commercial ocean iron enrichment. The convention allows enrichment for research purposes as long as it is controlled and does not harm the environment.

Buesseler and others added iron to the ocean in dozens of experiments in the 1990s and 2000s. But in 2012, a public backlash against interfering with Earth's natural systems emerged after American entrepreneur Russ George the infamous reset 100 tons of iron dust off the coast of Canada, partly to stimulate salmon fishing.

ExOIS promises detailed monitoring of the effects of its field studies, as well as improved computer modeling of the consequences. Scientists will add a non-reactive tracer such as sulfur hexafluoride to the iron sulfate solution, a step that will help track the spread of the fertilized water as the iron sulfate slowly breaks down. They will measure CO₂ concentrations using ships, floats and underwater drones. And they will check satellite images that may show an increase in the color of phytoplankton on the ocean surface. The group also promises more public participation and attention to environmental impacts than previous iron-dissemination projects.

The effects can be varied and wide-ranging. In a 2009 experiment in the southwest Atlantic Ocean by German and Indian scientists, larger zooplankton ate smaller phytoplankton, and little carbon actually reached the deep sea. In a 2006 experiment in the northeast Pacific Ocean by researchers from the U.S. and Canada, toxic phytoplankton species flourished. This has raised concerns that fertilization could create “dead zones” where lush algae blooms consume all the oxygen in the water, killing off other life. Phytoplankton blooms could also consume nutrients such as phosphorus and nitrogen, which would then be unavailable to organisms elsewhere, a phenomenon known as “nutrient theft.” In addition, scientists still know little about the deep ocean ecosystems where carbon is thought to be stored. “It’s likely that [iron fertilization] “It will impact things we don't fully understand yet,” says deep-sea expert Lisa Levin of the Scripps Institution of Oceanography, who is not involved in the ExOIS program.

Last year computer modeling research British, American and French researchers have found that adding one to two million metric tons of iron to the ocean each year could reduce carbon emissions by 45 billion metric tons by 2100. However, it would also starve other marine creatures of nutrients. Along with an estimated 15 percent reduction in marine biomass caused by warming, another 5 percent could be lost due to iron fertilization, especially in fishing grounds near the Atlantic, Pacific and Indian Ocean coasts. “I haven’t really seen [ExOIS] “To come up with a hypothesis about what's wrong with previous work… that either increases carbon output or minimizes negative impacts,” says Alessandro Tagliabue of the University of Liverpool in England, one of the lead authors of the study.

Buesseler argues that some difficult trade-offs like this may be necessary. “It’s a small change in biology compared to doing nothing and watching this planet boil,” he says.