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Applying Rock Dust to Croplands Could Absorb up to 2 Billion Tonnes of CO2 from the Atmosphere, Research Shows

  • Major new study shows adding rock dust to farmland could remove carbon dioxide (CO2) equivalent to more than the current total emissions from global aviation and shipping combined – or around half of Europe’s current total emissions
  • Research identifies the nation-by-nation potential for CO2 drawdown, as well as the costs and the engineering challenges involved
  • Findings reveal the world’s highest emitters (China, India and the US) also have the greatest potential to remove CO2 from the atmosphere using this method
  • Scientists suggest unused materials from mining and the construction industry could be used to help soils remove CO2 from the atmosphere

Adding crushed rock dust to farmland could draw down up to two billion tonnes of carbon dioxide (CO2) from the air per year and help meet key global climate targets, according to a major new study led by the University of Sheffield.

The technique, known as enhanced rock weathering, involves spreading finely crushed basalt, a natural volcanic rock, on fields to boost the soil’s ability to extract CO2 from the air.

In the first nation-by-nation assessment, published in Nature, scientists have demonstrated the method’s potential for carbon drawdown by major economies, and identified the costs and engineering challenges of scaling up the approach to help meet ambitious global CO2 removal targets. The research was led by experts at the University of Sheffield’s Leverhulme Centre for Climate Change Mitigation, and the University’s Energy Institute.

Meeting the Paris Agreement’s goal of limiting global heating to below 2C above pre-industrial levels requires drastic cuts in emissions, as well as the active removal of between two and 10 billion tonnes of CO2 from the atmosphere each year to achieve net-zero emissions by 2050. This new research provides a detailed initial assessment of enhanced rock weathering, a large-scale CO2 removal strategy that could make a major contribution to this effort. 

The authors’ detailed analysis captures some of the uncertainties in enhanced weathering CO2 drawdown calculations and, at the same time, identifies the additional areas of uncertainty that future work needs to address specifically through large-scale field trials.

The study showed that China, the United States and India – the highest fossil fuel CO2 emitters – have the highest potential for CO2 drawdown using rock dust on croplands. Together, these countries have the potential to remove approximately 1 billion tonnes of CO2 from the atmosphere, at a cost comparable to that of other proposed carbon dioxide removal strategies (US$80-180 per tonne of CO2).

Indonesia and Brazil, whose CO2 emissions are 10-20 times lower than the US and China, were also found to have relatively high CO2 removal potential due to their extensive agricultural lands, and climates accelerating the efficiency of rock weathering.

The scientists suggest that meeting the demand for rock dust to undertake large-scale CO2 drawdown might be achieved by using stockpiles of silicate rock dust left over from the mining industry, and are calling for governments to develop national inventories of these materials.

Calcium-rich silicate by-products of iron and steel manufacturing, as well as waste cement from construction and demolition, could also be processed and used in this way, improving the sustainability of these industries. These materials are usually recycled as low value aggregate, stockpiled at production sites or disposed of in landfills. China and India could supply the rock dust necessary for large-scale CO2 drawdown with their croplands using entirely recycled materials in the coming decades.

The technique would be straightforward to implement for farmers, who already tend to add agricultural lime to their soils. The researchers are calling for policy innovation that could support multiple UN Sustainable Development Goals using this technology. Government incentives to encourage agricultural application of rock dust could improve soil and farm livelihoods, as well as reduce CO2, potentially benefiting the world’s 2.5 billion smallholders and reducing poverty and hunger.

Professor David Beerling, Director of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and lead author of the study, said: “Carbon dioxide drawdown strategies that can scale up and are compatible with existing land uses are urgently required to combat climate change, alongside deep and sustained emissions cuts. 

“Spreading rock dust on agricultural land is a straightforward, practical CO2 drawdown approach with the potential to boost soil health and food production. Our analyses reveal the big emitting nations – China, the US, India – have the greatest potential to do this, emphasising their need to step up to the challenge. Large-scale Research Development and Demonstration programmes, similar to those being pioneered by our Leverhulme Centre, are needed to evaluate the efficacy of this technology in the field.”

Professor Steven Banwart, a partner in the study and Director of the Global Food and Environment Institute, said: “The practice of spreading crushed rock to improve soil pH is commonplace in many agricultural regions worldwide. The technology and infrastructure already exist to adapt these practices to utilise basalt rock dust. This offers a potentially rapid transition in agricultural practices to help capture CO2 at large scale.”

Professor James Hansen, a partner in the study and Director of the Climate Science, Awareness and Solutions Program at Columbia University’s Earth Institute, said: “We have passed the safe level of greenhouse gases. Cutting fossil fuel emissions is crucial, but we must also extract atmospheric CO2 with safe, secure and scalable carbon dioxide removal strategies to bend the global CO2 curve and limit future climate change. The advantage of CO2 removal with crushed silicate rocks is that it could restore deteriorating top-soils, which underpin food security for billions of people, thereby incentivising deployment.”

Professor Nick Pidgeon, a partner in the study and Director of the Understanding Risk Group at Cardiff University, said: “Greenhouse gas removal may well become necessary as we approach 2050, but we should not forget that it also raises profound ethical questions regarding our relationship with the natural environment. Its development should therefore be accompanied by the widest possible public debate as to potential risks and benefits.”

Ends

Contact

Sophie Armour, Media & PR Officer at the University of Sheffield: 07751 400 287 / 0114 222 3687 / sophie.armour@sheffield.ac.uk 

Notes

Embargoed study available here: https://drive.google.com/file/d/1m2zUuQMTd_KeJwH9wcNT8jHukHDOKKAs/view?usp=sharing 

FAQs on carbon drawdown with enhanced weathering developed by the Leverhulme Centre for Climate Change Mitigation are available here: http://lc3m.org/faqs/

The University of Sheffield

With almost 29,000 of the brightest students from over 140 countries, learning alongside over 1,200 of the best academics from across the globe, the University of Sheffield is one of the world’s leading universities.

A member of the UK’s prestigious Russell Group of leading research-led institutions, Sheffield offers world-class teaching and research excellence across a wide range of disciplines.

Unified by the power of discovery and understanding, staff and students at the university are committed to finding new ways to transform the world we live in.

Sheffield is the only university to feature in The Sunday Times 100 Best Not-For-Profit Organisations to Work For 2018 and for the last eight years has been ranked in the top five UK universities for Student Satisfaction by Times Higher Education.

Sheffield has six Nobel Prize winners among former staff and students and its alumni go on to hold positions of great responsibility and influence all over the world, making significant contributions in their chosen fields.

Global research partners and clients include Boeing, Rolls-Royce, Unilever, AstraZeneca, Glaxo SmithKline, Siemens and Airbus, as well as many UK and overseas government agencies and charitable foundations.

About the Leverhulme Trust

The Leverhulme Trust was established by the Will of William Hesketh Lever, the founder of Lever Brothers. Since 1925 the Trust has provided grants and scholarships for research and education.

Today, it is one of the largest all-subject providers of research funding in the UK, currently distributing £100 million each year. The Leverhulme Centre for Climate Change Mitigation at the University of Sheffield is part of a network of seven Leverhulme Trust research centres based in universities throughout the UK.

For more information about the Trust, please visit www.leverhulme.ac.uk  and follow the Trust on Twitter @LeverhulmeTrust

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

Native Plants Sequester Carbon in the Soil for Longer

Exotic plant species release 150 percent more carbon dioxide from the soil than native New Zealand plants, according to a new study from the Bio-Protection Research Centre published in Science.

The research is the latest development in an extended scientific debate over whether to prioritise planting native or exotic species to increase biodiversity and fight climate change.

While it doesn’t upset the longstanding scientific consensus that faster-growing plants sequester more carbon – and that exotic species planted outside their usual range will grow faster – the study does complicate the picture of the carbon cycle.

Carbon cycling and the soil

So what is the carbon cycle and how does CO2 get into the soil in the first place?

“It’s really important to think of it as a cycle,” the study’s lead author Dr Lauren Waller told Newsroom. Waller is a researcher at Lincoln University and a postdoctoral fellow at the Bio-Protection Research Centre.

While most people understand that plants remove carbon dioxide from the atmosphere, they don’t always realise what happens next.

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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

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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.

 

CONTINUE LEYENDO EN BBC NEWS MUNDO

Can Farmers and Ranchers Pull One Trillion Tons of Carbon Dioxide out of the Atmosphere?

The short answer is yes, they can.

First, a little background: atmospheric concentrations of carbon dioxide have been rising significantly since the beginning of the Industrial Revolution. In May, the Mauna Loa Observatory in Hawaii reported an average monthly level of carbon dioxide above 415 ppm, the highest concentration of atmospheric carbon dioxide in millions of years (I,II). This accumulation represents an additional 135 ppm of carbon dioxide in the atmosphere since the Industrial Revolution, which equates to one trillion tons* of carbon dioxide, or one teraton (III). **

To avoid the harshest effects of these additional greenhouse gases in the atmosphere, we must reduce current emissions – but even that will not be enough. Even if all countries meet their commitments under the Paris Agreement, and all companies meet their individual commitments, atmospheric carbon dioxide levels will continue to climb, reaching an estimated 580 ppm by the end of the century (IV). This uncertain future cannot be averted with a business-as-usual mindset, nor a middle of the road effort. Drawing down atmospheric carbon dioxide is necessary to begin undoing the damage.
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Farming Our Way Out of the Climate Crisis

Could changing our land use and agricultural practices make a dent in addressing climate change? Yes, says Project Drawdown and a new report from the IPCC.

The Intergovernmental Panel on Climate Change (IPCC) released a new report that highlights the importance of land use and agriculture in climate change.

Good! It’s a crucial area for us to focus on, and it’s often neglected.

I’ve been working on this topicon and offsince the 1990s, and have been bewildered why it doesn’t get more attention. For some reason, when we think of greenhouse gas emissions, we envision factories, cars, and smokestacks — not farm fields, plantations, and cattle ranches. But, it turns out, land use and agriculture are among the biggest contributors to climate change — and can be among the biggest climate solutions.

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Structurally Complex Forests Better at Carbon Sequestration

Forests in the eastern United States that are structurally complex – meaning the arrangement of vegetation is highly varied – sequester more carbon, according to a new study led by researchers at Virginia Commonwealth University.

The study demonstrates for the first time that a forest’s structural complexity is a better predictor of carbon sequestration potential than tree species diversity. The discovery may hold implications for the mitigation of climate change.

“Carbon dioxide, a potent greenhouse gas, is taken up by trees through the process of photosynthesis and some of that ‘fixed’ carbon is allocated to wood,” said Chris Gough, Ph.D., corresponding author on the study and an associate professor in the Department of Biology in the College of Humanities and Sciences. “Our study shows that more complex forests are better at taking up and sequestering carbon in wood and, in doing so, they leave less carbon dioxide in the air.”

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US Could Cut Emissions More Than One-Fifth Through ‘Natural Climate Solutions’ Like Reforestation

More than one-fifth of current greenhouse gas emissions in the United States could be kept out of the atmosphere and stored in the land, according to new research.

A study led by Joseph E. Fargione, director of science at The Nature Conservancy, looks at the natural solutions that could help the US do its part to keep global warming below 2 degrees Celsius (approximately 3.6 degrees Fahrenheit), the goal adopted by the 195 countries who signed the Paris Climate Agreement in December 2015.

Photo credit: Pexels

Fargione and team examined 21 natural climate solutions that increase carbon storage and help avoid the release of greenhouse gases into the atmosphere, including conservation and restoration initiatives as well as improved management of forests, grasslands, farmlands, and wetlands. According to a study published in the journal Science Advances last week detailing their findings, the researchers’ analysis reveals that all of these natural climate strategies combined could reduce global warming emissions by an amount equivalent to about 21 percent of US net emissions in 2016.

“We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year−1 [petagrams of CO2 equivalent per year], the equivalent of 21% of current net annual emissions of the United States,” the researchers write in the study. “NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.”

The majority — some 63 percent — of the climate mitigation potential of natural solutions in the US is due to increased carbon sequestration in plant biomass, with 29 percent coming from increased carbon sequestration in soil and 7 percent from avoided emissions of methane and Nitrous oxide. Of the 21 natural solutions the researchers analyzed, increased reforestation efforts had the largest carbon storage potential, equivalent to keeping 65 million passenger cars off the road.

Climate mitigation potential of 21 NCS in the United States. Credit: Fargione et al. (2018). doi:10.1126/sciadv.aat1869

“Reforestation has the single largest maximum mitigation potential (307 Tg CO2e year−1 [teragrams of CO2 equivalent per year]),” the researchers write. “The majority of this potential occurs in the northeast (35%) and south central (31%) areas of the United States. This mitigation potential increases to 381 Tg CO2e year−1 if all pastures in historically forested areas are reforested.”

Forests provide a number of other solutions with great potential, such as increasing carbon storage by allowing longer periods between timber harvests and reducing the risk of mega-fire through controlled burns and thinning of forests, the researchers found.

“One of America’s greatest assets is its land. Through changes in management, along with protecting and restoring natural lands, we demonstrated we could reduce carbon pollution and filter water, enhance fish and wildlife habitat, and have better soil health to grow our food — all at the same time,” Fargione said in a statement. “Nature offers us a simple, cost-effective way to help fight global warming.”

Fargione and his co-authors note that close to a million acres of forest in the US are converted to non-forest every year, mostly as a result of suburban and exurban expansion and development, but that this source of greenhouse gas emissions could be addressed with better land use planning.

“Clearing of forests with conversion to other land uses releases their carbon to the atmosphere, and this contributes to rising temperatures,” said co-author Christopher A. Williams, an environmental scientist and associate professor at Clark University in Massachusetts. “Land owners and land managers are thinking about how they might use their land base to slow the pace of climate change, but until now they lacked the data needed to assess this potential.”

Williams added: “We estimated how much forest is being lost each year across the U.S., and the amount of carbon that releases to the atmosphere. Turning these trends around can take a dent out of global warming, and now we know how much and where the potential is greatest.”

The researchers also estimated the emissions reductions that could be accomplished for $10, $50, and $100 per megagram of CO2 equivalent, and found that 25 percent, 76 percent, and 91 percent, respectively, of the maximum mitigation could be achieved at those prices. This is a key finding, they say, because “a price of at least USD 100 is thought to be needed to keep the 100-year average temperature from warming more than 2.5°C, and an even higher price may be needed to meet the Paris Agreement <2°C target.”

US President Donald Trump has said he plans to withdraw the United States from the Paris Climate Agreement, but the earliest any country can do so is 2020. The US’ Nationally Determined Contribution under the Paris Agreement calls for the country to reduce greenhouse gas emissions 26 to 28 percent below 2005 levels by 2025. Reaching that goal will require the US to drastically scale back the burning of fossil fuels, but this new study shows that NCS will also have a crucial role to play.

“Reducing carbon-intensive energy consumption is necessary but insufficient to meet the ambitious goals of the Paris Agreement,” the researchers write. “Comprehensive mitigation efforts that include fossil fuel emission reductions coupled with NCS hold promise for keeping warming below 2°C.”

Forest in Borderland State Park, Massachusetts. 35 percent of the climate mitigation potential of reforestation in the United States occurs in northeastern forests. Photo via Wikimedia Commons, licensed under CC0.

 

CITATION

• Fargione, J. E., Bassett, S., Boucher, T., Bridgham, S. D., Conant, R. T., Cook-Patton, S. C., … & Gu, H. (2018). Natural climate solutions for the United States. Science Advances, 4(11), eaat1869. doi:10.1126/sciadv.aat1869

Reposted with permission from Mongabay