California’s kelp forests have struggled to recover since the 2013–2017 marine heat wave, despite major restoration efforts by scientists, fishermen, tribes, and volunteer divers. The decline reflects a global trend tied to ocean warming, as the sea absorbs roughly 90% of the excess heat generated by fossil fuel emissions. According to a 2023 study in Nature Communications, kelp forests span about 2.8 million square miles – an area larger than the Amazon rainforest — and contribute an estimated $500 billion annually through fisheries, coastal protection, food products, and carbon sequestration. Alongside coral reefs, they are among the planet’s most productive ecosystems, yet they remain vulnerable to accelerating marine heat waves.

A 2026 study led by the National Oceanic and Atmospheric Administration (NOAA) and dozens of global research institutions found that the ocean absorbed more heat in 2025 than at any time on record, fueling unprecedented marine heat waves. These events can raise regional water temperatures by 5–10 degrees, devastating cold-water kelp ecosystems that evolved over 32 million years ago. Communities like Fort Bragg, California, have lost up to 95% of their kelp forests, with cascading economic impacts including the loss of recreational abalone fisheries valued at $25 million annually. Similar declines – often exceeding 80% – have been documented in Tasmania, Norway, Mexico, and Maine.

Despite the losses, kelp remains one of the fastest-growing organisms on Earth, capable of growing up to two feet per day. Restoration efforts offer cautious optimism: in Southern California, divers working with The Bay Foundation restored 80 acres of giant kelp near Palos Verdes by reducing sea urchin populations; South Korea has invested $29 million annually in kelp restoration, bringing back 50,000 acres of marine forest. Grassroots protections in places like the Azores and Chile have also helped safeguard wild kelp. Still, without a rapid transition away from fossil fuels, experts warn that the future of kelp forests may depend on sustained intervention, research funding – including proposed “Help Our Kelp” legislation – and broader climate action to preserve these underwater forests for both marine life and coastal communities.

Read the full article on the LA Times.

Title image by Josh Havelind