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Africa’s Forests Are Currently Emitting More CO2 Than They Absorb

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Congo’s rainforest ranks as the second largest globally

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Africa’s forests currently release more carbon dioxide than they can absorb, complicating global efforts to achieve net-zero emissions.

The continent’s forests and shrublands were once among the largest carbon sinks, contributing to 20% of all carbon dioxide absorption by plants. The Congo rainforest, the second largest in the world after the Amazon, is often termed the “lungs of Africa,” absorbing roughly 600 million tons of CO2 each year. Unfortunately, this vital ecosystem is diminishing due to logging and mining activities.

Recent research indicates that Africa’s forests lost an annual average of 106 million tonnes of biomass between 2011 and 2017, following a period of growth from 2007 to 2010. This loss translates to approximately 200 million tons of CO2 emissions annually, primarily linked to deforestation in the Congo. Heiko Balzter from the University of Leicester, UK, highlights this concerning trend.

“To lose tropical forests as a means of mitigating climate change means we must significantly reduce emissions from fossil fuel burning and strive for near-zero emissions,” he states.

Balzter and his team utilized satellite data to measure aspects like canopy color, water content, and height at selected locations to calculate biomass levels. These findings were compared to on-the-ground measurements, although such data are scarce in Africa.

However, Simon Lewis from University College London cautions that satellite technology cannot accurately identify tree species within a forest and fails to reliably estimate carbon absorption in forests with high biomass or emissions from those compromised by selective logging. For example, a dense hardwood like mahogany retains more carbon than a lighter wood like balsa of equivalent size.

“Deforestation rates in the Democratic Republic of Congo have surpassed those of the 2000s, a fact we cannot deny,” he asserts. “Nonetheless, it remains uncertain if this will significantly alter the carbon balance across the continent.”

The study also overlooks the wet peatlands that lie beneath much of the Congo rainforest. These peatlands absorb modest quantities of CO2 annually and sequester around 30 billion tonnes of ancient carbon.

In recent years, the Amazon rainforest, once a significant carbon sink, has emitted more CO2 than it absorbs. While deforestation in the Amazon is somewhat regulated, the situation is worsening in Congo.

In the Democratic Republic of Congo, impoverished farmers often clear rainforests for slash-and-burn agriculture, while many foreign-owned companies engage in illegal logging of valuable hardwoods such as African teak and coralwood.

During the recent COP30 climate summit in the Amazon, Brazil unveiled the Tropical Forests Forever Facility, a fund designed to provide investment returns to tropical nations at the rate of $4 per hectare of remaining forest. However, contributions to this fund have only reached $6.6 billion, a fraction of the $25 billion target.

Balzter believes this initiative could be more effective than carbon credits, which reward “avoided” emissions that often lack real value.

“It’s crucial to establish this tropical forest permanent facility swiftly if we intend to reverse the trend of increased carbon emissions from Africa’s tree biomass,” he emphasizes.

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Source: www.newscientist.com

Chemistry expertise speeds up rocks’ ability to absorb CO2

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Olivine rock naturally reacts with carbon dioxide, but it’s a slow business

Renhour48 via Wikimedia/CC0 1.0 Universal

The new process will allow crushed rocks to capture carbon dioxide more quickly from the air by turbocharged with already widely adopted carbon removal techniques.

Natural silicate minerals such as basalt react with water and CO2 to form solid carbonic acid materials, a process known as reinforced lock weathering (ERW). Research suggests Spreading crushed silicate rocks on farmland increases the amount of carbon the soil can absorb, while improving farmer crop yields.

but Matthew Canan Stanford University in California believes that the carbon advantage of ERW is exaggerated as natural silicates do not reach the climate quickly enough to extract large amounts of carbon from the atmosphere. “The data is very clear. They don’t weather at a useful speed,” he says.

Conversion of silicates into more reactive minerals increases weathering rates and makes ERW a viable climate solution, he says. Canaan and his colleagues Yuxuan Chen Stanford University also developed a method for producing magnesium oxide and calcium silicate using a process inspired by cement production.

“When you take calcium sources and magnesium silicate and heat it, you can make calcium silicate and magnesium oxide,” says Canaan. “The core reaction is what is called ion exchange, and it exchanges magnesium for calcium.”

“The reason it’s strong is because calcium silicate is reactive and so is magnesium oxide,” he says. “I put one reactive thing in and two come out.” The ingredients get the weather thousands of times faster than standard silicates, says Canaan.

The ki used in this process must be heated to 1400°C for the reaction, and energy may be provided by natural gas. This means that this method generates significant carbon emissions, but Canaan can capture these at sources or use several reactive minerals to capture the emissions at the site. It suggests that booking can offset it.

When the emissions associated with material production are taken into consideration, one ton of reactive material removes about one ton of carbon dioxide from the atmosphere. Researchers can now create 15 kilograms of reactive rocks per day, but they hope to turn the idea into a commercial venture by selling the materials to farmers for use on farmland.

Rachel James The University of Southampton, UK, challenges Canaan’s claim that traditional ERWs do not work, pointing to many documented examples of intensified weathering tests. However, she welcomes attempts to accelerate the weathering rate of silicate.

“The climate crisis now requires action, so what you can do to speed up weathering rates is extremely beneficial,” she says. “Weathering is essentially a slow process and frankly, we want to see meaningful carbon dioxide removal on a timescale of 10 years or more than 50 years.”

However, she warns that the team is likely to face problems with expanding production and deployment. She says that using minerals in agricultural systems does not guarantee that all captured carbon is permanently trapped.

Phil Renforth At Heriot Watt University in Edinburgh, UK, the proposal is said to be a smart idea, but it takes more research to understand how it should be unfolded. “They essentially produce cement minerals, which may not be an ideal candidate mineral in addition to agricultural soils,” he says.

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Source: www.newscientist.com

Scientists claim that New building biomaterial can absorb carbon dioxide from the atmosphere

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The new biomaterial, called C-ELM, incorporates live cyanobacteria in translucent panels that can be attached to the interior walls of buildings. The microbes embedded in these panels grow through photosynthesis, absorbing carbon dioxide from the air and attaching it to calcium through a biomineralization process to produce calcium carbonate, which traps carbon.

C-ELM is Camptonema Animal Cyanobacteria extracting carbon dioxide from the atmosphere. Image courtesy of Prantar Tamuli.

One kilogram of C-ELM (cyanobacterial engineered biomaterial) can capture and sequester up to 350 grams of carbon dioxide, while the same amount of traditional concrete releases as much as 500 grams of carbon dioxide.

A 150-square-metre wall covered with these C-ELM panels will trap around one tonne of carbon dioxide.

“By developing C-ELM materials, my goal is to transform the construction of future human settlements from one of the largest carbon emitting activities into one of the largest carbon sequestration activities,” said Planter Tamri, a graduate student at University College London.

“I was inspired to develop this material through my study of stromatolites – natural stone structures that formed over millions of years from sediments trapped by algal mats, the oldest living organisms on Earth.”

Tamri et al. Camptonema AnimalA type of photosynthetic cyanobacteria, it grows in long filamentous structures that help attach the microbes to the surrounding material within the panel.

The calcium carbonate produced by the cyanobacteria helps strengthen the panels.

The panels themselves are designed to provide a variety of aesthetic and structural benefits to buildings.

It is lightweight, sound absorbing, translucent enough to let light through, and has insulating properties, making buildings more energy efficient.

The first such panel was unveiled at an exhibition in the “Bioscope” pavilion at St. Andrews Botanic Garden in Scotland.

Designed by design collective Studio Biocene, the exhibit showcased low-carbon, low-impact building methods that mimic the natural environment.

“The potential of this type of biomaterial is enormous,” said Professor Marcos Cruz, from University College London.

“If mass-produced and widely adopted, it has the potential to dramatically reduce the construction industry's carbon footprint.”

“We hope to scale up the production of this C-ELM and further optimize its performance to make it suitable for use on construction sites.”

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This article is a version of a press release provided by University College London.

Source: www.sci.news