What Kelp Forests Can Do for the Climate

Sixty years ago, Tasmania’s coastline was cushioned by a velvety forest of kelp so dense it would ensnare local fishers as they headed out in their boats. “We speak especially to the older generation of fishers, and they say, ‘When I was your age, this bay was so thick with kelp, we actually had to cut a channel though it,’” says Cayne Layton, a postdoctoral research fellow at the Institute for Marine and Antarctic Studies at the University of Tasmania. “Now, those bays, which are probably at the scale of 10 or 20 football fields, are completely empty of kelp. There’s not a single plant left.”

Since the 1960s, Tasmania’s once expansive kelp forests have declined by 90% or more. The primary culprit is climate change: These giant algae need to be bathed in cool, nutrient-rich currents to thrive, yet regional warming in recent decades has extended the waters of the warmer East Australian Current into Tasmanian seas to devastating effect, wiping out kelp forests one by one. Warming waters have also boosted populations of predatory urchins, which gnaw on kelp roots and compound the loss.

Tasmania isn’t the only site of destruction. Globally, kelp grow in forests along the coastlines of every continent except Antarctica; most of these are threatened by climate change, coastal development, pollution, fishing, and invasive predators. All of this matters because these ecosystems provide huge benefits: They cushion coastlines against the effect of storm surges and sea level rise; they cleanse water by absorbing excess nutrients; and they also slurp up carbon dioxide, which can help drive down ocean acidity and engineer a healthy environment for surrounding marine life. These forests—which in the case of the giant kelp species that grows in Tasmania, can reach heights of 130 feet—also provide habitat for hundreds of marine species.

Having spent years studying these benefits, Layton is now trying to bring a patch of Tasmania’s struggling kelp forests back to life. Every few weeks, he dives out to inspect three 39-by-39-feet plots he’s created off the coast, each containing fronds of baby kelp, springing from ropes that are tethered to the ocean floor. These kelp nurseries are part of Layton’s project to determine whether climate-resilient “super-kelp” that has been raised in a laboratory will fare better in Tasmania’s changing seas. But his experiment also brings attention to the extraordinary potential of kelp to absorb carbon and help tackle climate change.

Climate-Forward Kelp

The capacity to draw CO2 from the atmosphere has added “climate mitigation” to kelp’s list of benefits. When we talk about ways oceans can sequester carbon, the conversation typically revolves around mangroves, salt marshes, and seagrass meadows. But “the magnitude of carbon sequestered by algal forests is comparable to that of all those three habitats together,” says Carlos Duarte, a professor of marine science at the King Abdullah University of Science and Technology in Saudi Arabia. “Algal forests should not be left behind. They have been hidden for much too long.”

There’s a lot we still don’t understand about how kelp store CO2. But researchers are starting to build a better picture of this giant seaweed and how we might improve its capacity to help tackle climate change.

The dilemma is that kelp itself is also under siege from warming seas—which is the focus of Layton’s work. Of Tasmania’s original forest, only around 5% remains. Researchers think these plants have survived through natural variation and selection.

“There do seem to be individuals that are adapted and capable of living in the modern conditions in Tasmania that we have created through climate change,” Layton explains.

From this remaining pool of wild giant kelp, he and his colleagues have identified what Layton calls “super kelp” that may be more resilient against the effects of warming seas. From these he has harvested spores, embedding them in twine to be wound around the ropes that are rooted into the sea floor. The hope is that these super kelp spores will develop into saplings that will in turn set their own spores adrift on ocean currents, seeding new mini-forests nearby.

“For giant kelp restoration to work at the scale of the coastline, we’ll need to plant many of these seed patches,” Layton explains. “The idea is that, over time, those will self-expand, and eventually coalesce—and there’s your giant kelp forest back.”

Other kelp restoration projects around the world are tackling different threats. In Santa Monica Bay, California, conservationists are trying to save local kelp forests from voracious purple urchins, whose population has exploded since a major predator—the sea otter—dramatically declined decades ago. The urchins’ unchecked appetite has contributed to the loss of three-quarters of the bay’s former kelp forest. But fishers are carefully hand-clearing urchins—the draw being that as kelp is restored, fisheries are too. So far they’ve managed to clear 52 acres (21 hectares), which the kelp forest has reclaimed.

“All we had to do is clear the urchins out of the way,” says Tom Ford, executive director of The Bay Foundation, which is leading the effort.

The project’s success has caused others to ponder its carbon sequestration potential, Ford says. The city of Santa Monica recently established a goal of reaching carbon neutrality by 2050, and asked The Bay Foundation how kelp restoration could factor into that. A nonprofit called Sustainable Surf has also launched a program enabling people to invest in the kelp restoration project to offset their own carbon footprints.

“These kelp forests grow so fast and suck in tremendous amounts of carbon,” Ford says. In California, there’s a focus on preserving wild lands with carbon credits, he explains. But the uptick in regional wildfires means that land-based forests might no longer seem like the safest bet. “Now, working off the coast is becoming perhaps a more important option.”

Similarly, in the United Kingdom, a plan known as “Help Our Kelp” aims to restore a 70-square-mile tract of historic kelp forest along the country’s southern Sussex Coast. It has attracted the interest of two local councils and a water company, which are intrigued by its potential to provide a new carbon sink. “All three organizations are interested in carbon, but also interested in the wider benefits [of kelp forests],” explains Sean Ashworth, deputy chief fisheries and conservation officer at the Association of Inshore Fisheries and Conservation Authorities, a partner on the project.

Captured Carbon?

Yet key questions remain about where all the stored carbon ends up. Trees stay in one place, so we can reasonably estimate how much carbon a forest stores. Kelp, on the other hand, can float off to unknown destinations. If it begins to decompose, its stored carbon may be released back into the atmosphere, explains Jordan Hollarsmith, a marine ecologist at Simon Fraser University and the Department of Fisheries and Oceans in Canada. “Truly removing that carbon from the global carbon budget would require that those kelp fronds somehow be buried, or transported to the deep sea,” she says.

In fact, emerging research is beginning to paint a picture of seaweed’s journey through the ocean. A 2016 study estimated that about 11% of global macroalgae is permanently sequestered in the ocean. The bulk of that, about 90%, is deposited in the deep sea, while the rest sinks into coastal marine sediments.

“If the algae reaches below the 1,000-meter horizon, it is locked away from exchange with the atmosphere over extended time scales, and can be considered permanently sequestered,” says Dorte Krause-Jensen, a professor of marine ecology at Aarhus University in Denmark and author on the 2016 study along with Duarte. Still, the challenge of tallying this up remains. Compared with mangroves, seagrasses, and salt marshes, which deposit carbon directly and reliably into the sediments below, the inherent changeability of a kelp forest makes the sequestration harder to accurately quantify. But this could change, Duarte say, if kelp forests came under strict human management—something that’s already happening with smaller species of seaweed that are being farmed worldwide for food products and fertilizer.

Future Kelp

Could we similarly bring vast kelp forests under human control for the benefit of the planet? Brian Von Herzen, executive director of the nonprofit The Climate Foundation, thinks so. The Climate Foundation is a partner on Cayne Layton’s project for climate-resilient kelp, and Von Herzen is a major player in the field of marine permaculture, a type of open-ocean seaweed farming that mimics wild kelp forests to regenerate marine ecosystems, boost food security and sequester carbon.

Von Herzen is now trying out prototype arrays in the Philippines to help make seaweed farming more resilient to climate change. Central to Von Herzen’s vision is an array on which kelp would grow, hovering about 80 feet below the ocean’s surface. Using solar, wind, and wave energy to drive their motion, hoses fixed beneath the structure would siphon up colder, nutrient-rich water from the depths below. This cool water infusion would re-create an ideal micro-environment for the tethered kelp to thrive; the kelp would then oxygenate the water and create new fish habitat—all while capturing carbon, Von Herzen explains.

While these deepwater kelp forests are only hypothetical, Von Herzen is now testing prototype arrays in the Philippines to help make seaweed farming more resilient to climate change. Seaweed farmers there have suffered major losses because of warm ocean currents that sweep in and decimate their crops. But with the upwelling of cooler water generated by the new arrays, seaweed is starting to flourish again.

This project, and others being developed off the coasts of Europe and the U.S., are laying the groundwork for Von Herzen’s ultimate ambition: To dramatically scale up kelp arrays, eventually spanning great tracts of deep ocean where they could collectively absorb billions of tons of CO2 while also providing food security in the form of shellfish aquaculture and fish habitat and providing what he calls “ecosystem life support.”

Kelp could be buried in the deep sea to sequester carbon or be harvested to produce low-emissions biofuel and fertilizers, he says. “We use the thriving wild kelp forest as the ecosystem model for what we can scale in the oceans,” Von Herzen says.

Current Benefits

On the back of her research, Krause-Jensen is optimistic about the carbon sequestration potential of kelp and the possibility that it could be dramatically enlarged by sustainable farming. But practically speaking, in nations such as Australia and the United States, Duarte says, “it’s harder to get a concession for a seaweed farm than for oil and gas exploration.” And global systems for providing compensation for sequestering carbon are not yet set up to accommodate kelp.

Christophe Jospe, the chief development officer at Nori, a company that is working to make it easier to fund carbon removal initiatives, argues that with such a powerful sequestration tool at our disposal, we should accelerate its acceptance—even if seaweed farmers are only able to guarantee sequestration for, say, 10 years.

“We are throwing ourselves into a heated environmental debate where people say, well, that’s not permanent. But nothing is permanent—and it’s the reservoir of carbon that we need to increase because of the climate crisis that we’re in,” he says. “So actually, it’s a huge environmental value for a program to ensure 10 years of permanence.”

Things might gradually be moving in that direction. Working with Oceans 2050, a global alliance to restore the world’s oceans led by Alexandra Cousteau, Duarte is now helping to develop a carbon credit program that could be applied to seaweed farming. This makes it possible to imagine a world where we might one day invest carbon credits in kelp farms or where wild forest restoration might count as mitigation.

Meanwhile, back in Tasmania, Layton continues to watch over his nurseries of infant kelp, and he urges us to be cognizant of what kelp forests are already doing for us right now.

“They’re exactly like forests on land. There aren’t many people questioning their value,” he says. “Some people might not be interested in seaweed. But they may be interested in fishing, or their beachfront property not getting washed away, or making sure that their coastal waters are clean. All of those things are intimately tied to kelp forests.”

Reposted with permission from Yes Magazine

A Vision for the Social and Ecological Regeneration of Mexico City’s Xochimilco Wetlands

By Mayra Rubio Lozano

MEXICO CITY – Xochimilco is a city south of Mexico City best known for its canals. The area’s wetlands,  recognized for their important biological and cultural value, are why Xochimilco is named as a World Heritage Site (UNESCO) and Site of Agricultural Importance (FAO). 

Humedalia is a Mexican organization that works for the conservation and restoration of the Mexican wetlands. It is part of the Regeneration International partner network and as such, has applied for the Scientific and Technical committee evaluation program of the 4 per 1000 initiative

Humedalia’s work focuses on the chinampas of Xochimilco. (Chinampas refers to a system of growing crops in floating gardens created in shallow lake beds, using farming techniques developed by the Aztecs).

Agricultural production in chinampas, or islands of arable land, started over 800 years ago.  When the first tribes that settled in the Mexico basin, they were able to produce 4t/ha of crops. These high yields allowed the development of big urban settlements, such as what we have today in Mexico City. These cities generated a big demand for water resources, and ultimately led to the transfer of agriculture to urban soil.

Today, Xochimilco’s wetland and its landscape of chinampas retain only 2 percent of the fresh water that was originally in the basin. This agricultural landscape is highly threatened by processes linked to urbanization and the devaluation of the farmers’ labor. About  80 percent of the chinampas are abandoned, and water pollution has deteriorated the soil’s fertility. The few agricultural producers that remain face steep competition and low profits, because the intensive agricultural model, mostly subsidized, has forced these producers to lower the prices.

Despite the negative impact of urbanization, Xochimilco’s wetlands remain vital for Mexico City. They provide multiple environmental benefits, such as microclimate regulation, water catchment and recharge of the groundwater reserves, oxygen and food production, nutrient recycling and carbon sequestration. In a city where air pollution levels usually exceed healthy standards, carbon sequestration is fundamental for the city’s resilience. Wetlands sequester large amounts of carbon (0.4-32 Mg ha-1 year-1) in their sediments because of their anaerobic conditions, which slow the rate of decay of organic matter, facilitating carbon accumulation. In turn, carbon sequestration can be optimized by using traditional farming techniques (sustainable) in the chinampas in combination with new organic farming techniques, such as the biointensive method. 

This project seeks to increase carbon sequestration through a water-soil systemic approach. By restoring canals and rehabilitating hectares of idle land, the quality of the water available for watering will improve, and the chinampas’ soil will be regenerated, leading to an increase in the amount of the ecosystem’s carbon sequestration.

The project also will contribute to the local endemic flora and fauna’s habitat protection, such as the axolotl Ambystoma mexicanum, a type of salamander known as the Mexican walking fish. Protecting local flora and fauna will help restore the cultural identity linked to ancestral agriculture that survives in the hands of traditional farmers.

This project for regenerating the chinampas soil (rehabilitation, growing and maintenance) will provide the local community opportunities to increase family income and engage multiple generations, creating a space for the exchange of knowledge and experiences about ancestral farming techniques. Women and children who typically don’t participate directly in food production can become involved in marketing, sales and processing. 

In turn, regenerated chinampas will produce healthier foods. 

As part of the Regeneration International partner network, and applying for the 4 per 1000 initiative, Humedalia project helps improve socio-ecological conditions of Xochimilco’s wetland. Carbon sequestration will have a positive direct impact on the air quality of one of the most polluted cities in the world. But the project will also focus on the social aspect, improving the wellbeing of the community by generating self-employment at the chinampas, and creating the right conditions for social participation through collaborative networks that strengthen the community. 

Mayra Rubio Lozano is director of scientific research and sustainable development for Humedalia A.C. To keep up with Regeneration International news, sign up for our newsletter.


Una visión para la regeneración social y ecológica del humedal de Xochimilco en la Ciudad de México

Por Marya Rubio Lozano


El humedal de Xochimilco es un sitio que alberga un valor biológico y cultural importante Por esta razón es considerado Patrimonio de la Humanidad (UNESCO) y Sitio de Importancia Agrícola Mundial (FAO).

Humedalia es una organización mexicana dedicada a la conservación y restauración de los humedales mexicanos. Forma parte de la red de afiliados de Regeneration International y como tal ha aplicado al programa de asesoría científica y técnica de la iniciativa 4 por 1000.

El trabajo de Humedalia se concentra en las chinampas de Xochimilco (Chinampas se refiere a un sistema de cultivos en jardines flotantes creado en lechos de lagos poco profundos, utilizando técnicas agrícolas desarrolladas por los aztecas).

La producción agrícola en chinampas, o islas de tierra cultivables, data de hace más de 800 años, cuando las primeras tribus que se establecieron en la Cuenca de México alcanzaban a producir 4 t/ha de cultivos. Esta alta producción permitió el desarrollo de grandes asentamientos urbanos hasta lo que hoy en día conocemos como la Ciudad de México. Estas urbes generaron una gran demanda de recursos hídricos y una transformación del suelo agrícola a urbano.

Actualmente, el humedal de Xochimilco y su paisaje de chinampas representan el 2% del agua dulce que originalmente había en la Cuenca. Este paisaje agrícola se encuentra altamente amenazado por procesos ligados a la urbanización y devaluación del trabajo campesino. Alrededor del 80% de las chinampas se encuentran abandonadas y la contaminación del agua ha deteriorado la fertilidad del suelo. Además, los pocos productores agrícolas que quedan en el lugar enfrentan una alta competencia con modelos de producción intensivos (mayormente subsidiados) y los precios de sus productos son castigados disminuyendo la rentabilidad de su trabajo.

Por otra parte, el humedal de Xochimilco es vital para la Ciudad de México debido a los múltiples beneficios ambientales que le brinda, tales como regulación del microclima, captación de agua y recarga de mantos acuíferos, producción de oxígeno y alimentos, reciclamiento de nutrientes y secuestro de carbono. En un sitio donde la calidad del aire comúnmente supera los niveles saludables de contaminación en el aire, el secuestro de carbono es fundamental para la resiliencia de la Ciudad. Los humedales secuestran grandes cantidades de carbono (0.4-32 Mg ha-1 año-1) en sus sedimentos gracias a las condiciones anaerobias que éstos presentan, lo cual permite que la tasa de descomposición de la materia orgánica sea baja y se favorezca la acumulación de carbono. A su vez, este beneficio se puede potencializar al trabajar las chinampas con técnicas de cultivo tradicional (sostenibles) en sinergia con nuevas técnicas de cultivo orgánicas como el método de cultivo biointensivo.

Este proyecto busca incrementar el secuestro de carbono mediante un enfoque sistémico agua-suelo. A partir de la restauración de los canales y la rehabilitación de hectáreas de tierras ociosas, se mejorará la calidad de agua disponible para riego y se regenerará el suelo de las chinampas, incrementado la cantidad de secuestro de carbono del ecosistema.

Asimismo, el proyecto contribuirá a la protección de hábitat para la flora y fauna endémica del lugar como el axolotl Ambystoma mexicanum, y ayudará a recuperar la identidad cultural vinculada a la agricultura milenaria que sobrevive en las manos de los agricultores tradicionales.

Este proyecto de regeneración del suelo chinampero (rehabilitación, siembra y mantenimiento), brindará una opción redituable a miembros de la comunidad local para aumentar sus ingresos y la oportunidad de vincular distintas generaciones en el trabajo, creando un espacio itinerante para el intercambio de saberes y experiencias sobre las prácticas de cultivo ancestrales. A su vez, las chinampas regeneradas producirán alimentos más saludables. A través de su venta y/o transformación se integra a otro sector familiar, las mujeres y niños de la comunidad, que culturalmente no suelen participar directamente en la producción.

Y a su vez, las chinampas regeneradas producirán alimento más saludable.

Como parte de la red de Regeneration International y presentándose a la iniciativa 4 por 1000, el proyecto de Humedalia ayuda a mejorar las condiciones socioecológicas del humedal de Xochimilco. El secuestro de carbono beneficiará directamente a la calidad del aire de una de las ciudades más contaminadas del mundo, pero el proyecto interviene también en la esfera social del sitio, mejorando el bienestar de la comunidad generando autoempleo por el trabajo de las chinampas, y sembrando condiciones para la participación social a través de la generación de redes de colaboración que fortalezcan a la comunidad.

Mayra Rubio Lozano es directora de investigación científica y desarrollo sostenible para Humedalia A.C. Para mantenerse al día con las noticias de Regeneration Internationalsuscríbase a nuestro boletín.

How South Africa’s Mangrove Forests Store Carbon and Why It Matters

Scientists around the world are looking for ways to remove carbon dioxide from the atmosphere. This gas is a natural component of the atmosphere, released by processes of respiration and decomposition of organic matter.

But human activities that involve the burning of fossil fuels such as coal have released a lot of carbon dioxide into the atmosphere since the Industrial Revolution of the 1800s.

The accumulation of carbon dioxide in the atmosphere is directly linked to global warming. Climate-related risks for the environment and for human societies have been observed in the form of increased mean temperatures and a higher frequency at which extreme events – heatwaves, droughts, wildfires, floods, and storms—are occurring around the world.

One of the natural ways that carbon dioxide can be taken out of the atmosphere is the process of photosynthesis by plants. Plants absorb carbon dioxide, use the carbon for their growth, and release the oxygen back into the air. mangr


Cambio climático: qué es el carbono azul y por qué es tan importante para la lucha contra el calentamiento global

Si piensas en una solución natural que ayude a combatir el cambio climático. ¿Cuál es la primera que se te viene a la mente?

Seguro pensaste algo como sembrar más árboles o proteger los bosques y las selvas.

Y es cierto, los árboles juegan un rol fundamental en producir oxígeno y capturar dióxido de carbono, uno de los principales gases que producen el efecto de invernadero que calienta al planeta.

Existe, sin embargo, una trampa que captura CO2 de manera más rápida y eficaz que los bosques.

Se trata de los ecosistemas marinos costeros como los manglares, pantanos y humedales, donde se entierran grandes cantidades de carbono.

A ese carbono atrapado bajo el agua se le llama “carbono azul” y aunque a veces pasa desapercibido, mantenerlo bien aprisionado es vital para la salud del planeta.