Study Casts Doubt on Idea That Melting Glaciers Could Slow Climate Change

New research finds Antarctic ice shelf meltwater contributes little iron to feed algal blooms that could draw down CO2.

Published on Feb. 26, 2026

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A new study published in Nature Communications Earth & Environment has found that meltwater from an Antarctic ice shelf contains far less iron than previously thought, undermining the theory that glacial melt could help slow climate change by feeding algal blooms that pull CO2 out of the atmosphere. The researchers collected water samples at the Dotson Ice Shelf and found that meltwater only contributed about 10% of the dissolved iron, with the majority coming from inflowing deep ocean water and shelf sediments.

Why it matters

The iron fertilization theory has been a longstanding idea for how melting glaciers could potentially help offset climate change, but this new evidence casts doubt on that notion. Understanding the complex interplay between glacial melt, ocean processes, and the global climate is crucial for accurately modeling future climate scenarios.

The details

The researchers embarked on an expedition to the Amundsen Sea in West Antarctica, which has the highest rates of ice shelf thinning in the region. They collected water samples where seawater enters and exits a cavity beneath the Dotson Ice Shelf, and analyzed the iron content and isotopic ratios. The analysis revealed that meltwater only contributed about 10% of the dissolved iron, while 62% came from inflowing deep ocean water and 28% from shelf sediments.

  • The study was published in the journal Nature Communications Earth & Environment in February 2026.

The players

Rob Sherrell

A biogeochemistry professor at Rutgers University and the principal investigator on the study.

Venkatesh Chinni

The lead author of the study and a postdoctoral researcher at Rutgers University.

Amundsen Sea

A region in West Antarctica that has the highest rates of ice shelf thinning and accounts for most of the sea level rise driven by Antarctic melting.

Dotson Ice Shelf

The Antarctic ice shelf where the researchers collected water samples to analyze the iron content of the meltwater.

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What they’re saying

“Our claim in this paper is that the meltwater itself carries very little iron, and that most of the iron that it does carry comes from the grinding up and dissolving of bedrock into the liquid layer between the bedrock and the ice sheet, not from the ice that is driving sea level rise.”

— Rob Sherrell, Biogeochemistry professor at Rutgers University (Gizmodo)

What’s next

The researchers note that a true understanding of the subglacial processes involved in iron flux requires additional research, as they only investigated one Antarctic ice shelf. Verifying whether the fundamental balance of dissolved iron sources they observed at the Dotson Ice Shelf applies to other ice shelves will also require further study.

The takeaway

This study provides compelling evidence against the longstanding theory that melting glaciers could help slow climate change by feeding iron-fueled algal blooms that draw down atmospheric CO2. It highlights the complex and nuanced interplay between glacial melt, ocean processes, and the global climate system, underscoring the importance of field research to validate climate models and theories.