With the race to mitigate climate change intensifying, novel carbon removal technologies are attracting significant attention from governments, investors, and climate advocates alike. One such innovation comes from Israeli startup Gigablue, which claims to harness the natural carbon-absorbing power of algae in ocean environments.
By promoting rapid algal blooms through engineered nutrient releases, Gigablue aims to sequester atmospheric carbon dioxide at scale — offering carbon credits to corporations and nations seeking to offset emissions.
Proponents hail the concept as an elegant, nature-inspired solution that could supplement terrestrial carbon capture methods like afforestation and direct air capture.
Oceans cover over 70% of the planet’s surface and already absorb about a quarter of global CO₂ emissions annually, making them a tempting frontier for enhanced carbon removal efforts.
However, experts are voicing serious concerns about the ecological and ethical implications of such ocean interventions. Critics argue that Gigablue’s method bears a striking resemblance to iron fertilization, a controversial geoengineering technique involving the dumping of iron filings into ocean waters to stimulate phytoplankton blooms.
This practice was effectively banned under international agreements like the London Protocol and Convention on Biological Diversity due to uncertain outcomes, potential harm to marine ecosystems, and the lack of long-term environmental data.
While Gigablue insists its proprietary blend of nutrients differs from traditional iron fertilization, marine biologists and environmental watchdogs warn that any artificial manipulation of oceanic nutrient cycles risks unintended side effects — from oxygen depletion and dead zones to disruptions in marine food webs.
One of the most pressing issues is the lack of independent, peer-reviewed data supporting Gigablue’s claims. While the company touts early field trials and positive modeling projections, critics argue that ocean-based carbon removal projects demand rigorous, multi-year ecological monitoring before being deployed at scale.
“Just because something sequesters carbon doesn’t mean it’s harmless,” says Dr. Eliora Ben-David, a marine ecologist at Tel Aviv University. “We’ve seen repeatedly in environmental science how interventions with good intentions can backfire in complex ecosystems like the ocean.”
Moreover, global regulatory frameworks for marine geoengineering remain underdeveloped. Gigablue’s pilot projects, reportedly launched in regions with lax oversight, highlight a governance gap that could allow high-risk carbon removal experiments to proceed without sufficient environmental safeguards or public transparency.
Another point of contention is the sale of carbon credits based on oceanic carbon removal schemes whose durability and ecological impact remain unverified. Climate finance experts caution that premature commodification of such credits risks undermining carbon markets’ credibility.
“The voluntary carbon market is already plagued by credibility issues,” says Yossi Barak, a climate policy analyst. “Issuing credits from poorly monitored ocean interventions adds a layer of opacity that could do more harm than good.”
As global interest in carbon dioxide removal (CDR) technologies accelerates, the Gigablue episode serves as a case study in the tension between climate innovation and environmental caution.
While marine-based carbon capture holds theoretical promise, scientists and policymakers emphasize the need for robust scientific scrutiny, regulatory oversight, and transparent stakeholder engagement before embracing large-scale interventions in the world’s oceans.
In the absence of such safeguards, the risks — both ecological and reputational — may outweigh the potential carbon removal benefits. As the climate crisis demands urgent action, experts insist that speed must not come at the cost of science-based prudence.