Guardians of the Golden Coast: Why Kelp Forests Are Our Best Climate Ally 

September 10, 2026

ocean

By: Skye Porter

Research Support: Gabriella Willams

Guardians of the Golden Coast: Why Kelp Forests Are Our Best Climate Ally 

Kelp Forests are Climate Infrastructure

Swaying with the current, bright orange garibaldi darting to and fro, sea lions weaving through kelp forests are among the most iconic habitats in California’s coastal ecosystems. However, they are more than just their scenery. Kelp forests are one of the most vital ecosystems on the planet. They support biodiversity, fisheries, water quality, carbon cycling, and more. In a time where climate change is more pressing than ever, kelp forests will be one of our most powerful allies.

The Value of Kelp

Kelp proves to be invaluable not only to our ecosystems but fiscally. A recent global assessment found that kelp forests generate approximately $500 billion in ecosystem services each year worldwide, far more economically valuable than previously recognized. On average, a single hectare of kelp forest provides between $64,400 and $147,100 worth of benefits annually in services such as fisheries production, nitrogen cycling, and carbon removal.

Some of kelp’s greatest measurable economic benefits come from supporting fisheries and improving water quality. Kelp forests provide habitat for numerous keystone species such as: lobster, abalone, and finfish, all while removing excess nitrogen from our coastal waters. This natural filtration helps to improve water quality for nearby communities and maintain healthier ecosystems.

Kelp forests continue to function as globally significant blue carbon sinks. They remove an estimated 4.91 megatons of carbon annually, performing at rates comparable to terrestrial forests and mangroves. With roughly 740 million people living within 50 kilometers of a kelp forest, these ecosystems provide essential food security and environmental cleaning services that directly protect the livelihoods and water quality of nearly 10% of the global population (Eger et al., 2023).

When Heatwaves Push Kelp Over the Edge

As climate change drives more frequent heat waves; kelp forests are increasingly caught in the crossfire. Starting in 2014, Northern California went through a multi-year marine heatwave that took a serious toll on local kelp ecosystems. This warmer water causes nutrient deficiencies in the water, preventing healthy bull kelp growth, which leaves the forest under major stress.

At the same time, additional stressors increased, like the surge of kelp grazing purple sea urchin populations. With less kelp available and more grazing pressure, the ecosystem hit what researchers described as a synchronized environmental and biological breakdown. As the kelp vanished, large stretches of coastline turned into persistent urchin barrens, where little kelp could survive. Bull kelp was especially at risk because it is an annual species. Unlike giant kelp, which can live for several years, bull kelp has to reproduce successfully every year, so when heat stress and heavy grazing continued year after year, it became difficult for the kelp to bounce back. More than a decade later, many of these areas still have not fully recovered, showing how climate change can push kelp forests past a tipping point (McPherson et al., 2021).

Why Predators Matter for Kelp Recovery

Healthy kelp forests rely on productive environmental conditions, but they also depend on healthy food webs. Sea urchins naturally graze on kelp, and their populations are usually controlled by sunflower sea stars, California sheephead, or spiny lobsters. When these predators decline due to sickness such as sea star wasting disease, urchin populations can quickly explode and lead to overgrazing.

Research from California’s Northern Channel Islands found that ecosystems were most resilient when multiple predator species performed similar ecological roles. This concept, known as trophic redundancy, creates a biological safety net. If one predator species declines for some reason, the others can continue maintaining the urchin populations. The study also revealed that predator size matters. Large sheephead and lobsters were much better at controlling urchins than smaller individuals. To keep kelp forests intact, it’s necessary to protect both predator diversity and the size of these predators (Eisaguirre et al., 2020).

Protecting the Kelp Forests That Persist

Not all kelp forests contribute equally to long-term resilience. Using 35 years of satellite imagery, researchers identified areas of giant kelp that consistently persisted despite changing environmental conditions. These “persistent kelp forests” act as “climate-refugia,” and provide core stable habitat and sources of recovery from any disturbances.

However, the study also found that these critical habitats are often underprotected. While nearly 8% of kelp habitat in the Northeast Pacific falls within marine reserves, only about 4% of persistent kelp forests are actually protected. The protection gap is particularly concerning in Baja California, where less than 1% of kelp is protected despite being at the species’ warm-water limit and most susceptible to climate change (Arafeh-Dalmau et al., 2021).

How Marine Protected Areas Strengthen Resilience

Marine Protected Areas (MPAs) are crucial to strengthening the resilience of our kelp forests. Research from the Channel Islands showed that protected areas maintained healthier populations of sheephead and spiny lobsters. When sunflower sea star populations declined due to disease, these remaining predators continued controlling sea urchin populations, preventing widespread ecosystem collapse inside MPAs (Eisaguirre et al., 2020).

Furthermore, studies of giant kelp persistence suggest that placing MPAs around climate-resilient kelp forests can help protect the areas most likely to survive future change. Protecting these habitats increases the chances that they can continue serving as recovery sources for surrounding ecosystems (Arafeh-Dalmau et al., 2021). Together, these findings show that MPAs help preserve the relationships and ecosystem functions that make kelp forests more resilient in a changing climate.

Why Saving Kelp is Climate Action

Kelp forests support fisheries, improve water quality, store carbon, and provide habitat for countless marine species. But recent marine heatwaves and ecosystem shifts show that these benefits shouldn’t be taken for granted.

The science is clear: resilient kelp forests need both healthy environmental conditions and healthy ecological relationships. Protecting predator populations, conserving persistent kelp habitat, and reducing local stressors can all help these ecosystems to fight climate change.

MPAs are one of the best tools we have to achieve these goals. By protecting biodiversity, preserving ecosystem function, and safeguarding climate-resilient habitats, MPAs help ensure that kelp forests keep supporting both marine life and coastal communities.

To learn more about how WILDCOAST supports MPAs and kelp through our MPA Watch program, and how you can become a volunteer, check out our MPA Watch blogs here and here.

Sources:

Eger, A.M., Marzinelli, E.M., Beas-Luna, R. et al. The value of ecosystem services in global marine kelp forests. Nat Commun 14, 1894 (2023). https://doi.org/10.1038/s41467-023-37385-0

McPherson, M.L., Finger, D.J.I., Houskeeper, H.F. et al. Large-scale shift in the structure of a kelp forest ecosystem co-occurs with an epizootic and marine heatwave. Commun Biol 4, 298 (2021). https://doi.org/10.1038/s42003-021-01827-6

Arafeh-Dalmau, N., Cavanaugh, K.C., Possingham, H.P. et al. Southward decrease in the protection of persistent giant kelp forests in the northeast Pacific. Commun Earth Environ 2, 119 (2021). https://doi.org/10.1038/s43247-021-00177-9

Eisaguirre, J. H., J. M. Eisaguirre, K. Davis, P. M. Carlson, S. D. Gaines, and J. E. Caselle. 2020. Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics. Ecology 101(5):e02993. 10.1002/ecy.2993