About
Seaweeds are a diverse collection of organisms encompassing over 12,000 identified species separated into three groups: reds, browns, and greens. Kelp refers to over 100 species of large brown seaweed that thrive in cold, nutrient-rich waters, where they form complex ‘forest-like’ underwater habitats that are some of the most productive and diverse on Earth.
Take a journey through our interactive series to dive into how humanity can safeguard and restore underwater habitats.
Ecological Status and Trends
Over the past 50 years, up to 60 per cent of kelp forests have been degraded, according to UNEP’s report Into the Blue: Securing a Sustainable future for Kelp Forests. As cool-water species, kelp are stressed by ocean warming, marine heatwaves and other climate-related extremes, with extensive losses recorded at their warm range-edges. Overfishing, reduced water quality from excess nutrients, pollution and sedimentation, unregulated and unsustainable kelp harvesting also pose major threats to kelp forests.
Why Does it Matter?
Seaweeds play a crucial role in aquatic ecosystems by providing food and shelter to marine life, helping to sequester carbon from the atmosphere, producing oxygen, reducing damage from storms, filtering harmful pollutants, improving water quality and attracting tourists to their rich biodiversity.
Indigenous and coastal people have used seaweed and kelp as medicine, food and material for generations, with kelp forming part of their identities and fostering the development of a sense of place and connectedness with nature.
Maintaining healthy kelp ecosystems is critical for marine life and for communities around the world on their sustainable development pathways. Seaweed forests are also a crucial ally for addressing the triple planetary crisis of climate change, biodiversity loss and pollution. Protecting and restoring these forests can help countries deliver on SDG 14 (Life Below Water), and support other SDGs, including SDG 1 (No Poverty), SDG 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation), SDG 8 (Decent Work and Economic Growth), SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action).
What We Do
Engaging people who value and use seaweed sustainably and recognizing the value of seaweeds, particularly kelp, and their contribution to services such as fisheries production and carbon capture helps spur conservation and restoration efforts. To help spur restoration and conservation efforts, there is a clear need to engage people who value and use kelp sustainably and to recognize kelps’ value and contribution to services such as fisheries production and carbon capture.
As a relatively under-explored ecosystem UNEP works alongside initiatives such as the Global Seaweed Coalition with the aim of charting a path forward for the safe, sustainable and productive use and management of seaweed resources and to help close the existing research gaps in some of the risks, benefits and opportunities associated with seaweed farming/harvesting.
UNEP calls for a holistic approach to ecosystem management. By advancing area-based planning and management approaches such as marine spatial planning and marine protected areas, and sustainable management of harvesting of kelp and associated species, it is possible to maintain the integrity and health of kelp and other seaweed habitats.
See UNEP’s latest report on seaweed farming here to learn more about the potential of seaweed farming to be sustainably upscaled to deliver a wide range of potential climate, environmental and socioeconomic benefits.
Facts
- Kelp can act as a powerful ocean nature-based solution to adapt and mitigate climate change. This includes through sequestering carbon that can be buried in seafloor sediments and stored for centuries.
- Kelp are habitat-forming species that are vital to building underwater communities and nurturing species interactions.
- 61 per cent of data sets spanning over 20 years show significant declines in kelp abundance, with only 5 per cent showing increases.
- At present no global legal or policy instrument focuses explicitly on kelp.
- Nearly all (99.5 per cent) of farmed seaweed production occurs across 9 countries in East and Southeast Asia.
- As seaweeds absorb pollutants in coastal waters, large-scale seaweed farming in China likely absorbs most of the phosphorus inputs from land and approximately 6 per cent of the nitrogen inputs.
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