Marine Carbon Capture: Promising, but Not a Silver Bullet, Scientists Warn

Study Warns Marine CO2 Removal Methods Face Hurdles, May Not Be Climate Fix

A new study published today in Environmental Research Letters throws cold water on the idea that large-scale ocean-based techniques can rapidly mitigate climate change. Researchers from the University of East Anglia, the Institute for Marine and Antarctic Studies, and other institutions caution that limited understanding of the ocean environment creates significant hurdles for these methods.

The study, led by Dr. Philip Boyd, examines four “nature-based” approaches gaining traction: shellfish and seaweed farming, whale rewilding, and coastal wetland restoration. While these strategies offer environmental benefits, the authors warn against overstating their carbon capture potential.

“Upscaling these approaches brings complex ocean processes into play,” Dr. Boyd explains. “These processes could negate the intended climate benefits, and our current knowledge isn’t sufficient to accurately predict the outcomes.”

The research highlights several key challenges:

  • Uncertain Impact: Returning captured carbon to the atmosphere through natural processes is a major concern. Techniques like shellfish farming may not permanently store carbon if the shellfish are consumed or decompose.
  • Scalability Concerns: Scaling these methods to make a significant impact on global emissions remains a significant hurdle.
  • Verification Difficulties: Quantifying the actual amount of carbon dioxide removed from the atmosphere by these methods is currently difficult.

The authors recommend prioritizing research and development funding for methods that meet stricter criteria: safety, permanence of carbon storage, verifiability, and scalability. They argue that focusing on approaches that meet these criteria will provide policymakers with a more reliable toolkit for tackling climate change.

“There’s a real risk that resources are being directed at methods unlikely to deliver on their promises,” says Dr. Williamson, another researcher on the project. “We believe these approaches are more likely to be a form of greenwashing than the climate heroes some portray them as.”

The study emphasizes the importance of continued research into emissions reduction alongside exploration of carbon capture methods, both land-based and ocean-based, that meet the outlined criteria.