Efforts to Save Kelp Forests from Ocean Warming Are Ramping Up

In the coastal waters off British Columbia, tribal volunteers from the Haida Nation dive into the ocean to remove purple sea urchins. They work amid a dense forest of rippling golden-brown kelp fronds. Sunlight filters through the kelp canopy, creating a mesmerizing dance of light and shadow. Rays, sea lions, sharks, and bright orange garibaldi fish move through this underwater maze.

Kelp forests are biodiversity hotspots. They teem with a colorful variety of seaweeds, sponges, crustaceans, and other small ocean animals. Many of these species are found nowhere else on Earth. At one time, vast kelp beds grew in nutrient-rich shallow waters along roughly a third of the world’s coastlines. These forests helped to reduce the strength of waves and minimized coastal erosion. They also provided shelter for fish, invertebrates, and marine mammals.

Kelp forests are vanishing at an alarming rate. They are disappearing twice as fast as coral reefs and four times faster than tropical rainforests. An estimated 40 to 60 percent of kelp forests worldwide have been lost or significantly degraded in the last 50 years. These precipitous declines typically received far less scientific scrutiny than higher-profile ecological crises. However, kelp has gradually been getting more attention. Scientists and environmentalists now recognize the value of the carbon that coastal ecosystems, including kelp forests, can capture.

A 2023 literature review analyzed more than 180 papers examining the potential for kelp to store carbon. The review suggested that the climate benefits of these underwater forests may have been “grossly underestimated.” Albert Pessarrodana, a research fellow at the University of Western Australia and the review’s lead author, noted that kelps are one of the fastest-growing plants on the planet. He stated that they uptake as much carbon as tropical rainforests per unit of area.

Much of the carbon that kelp sequesters ends up being released back into the marine environment. Kelp is a macroalgae with leaflike structures called blades, which are its organs of photosynthesis. This plant matter, known as leaf litter or detritus, is typically eaten by fish and other marine organisms. They excrete it in a matter of days. Still, a small percentage of it ends up in the deep ocean, where it remains for centuries or even millennia. Two studies published in 2024 estimated that roughly 62 million tons of carbon are carried into the deep ocean by coastal currents each year.