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Biochar and carbon

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Biochar is a charcoal-like substance that is made by burning organic materials like crop and forestry wastes in a controlled process called pyrolysis, which is burning in an oxygen-deprived environment.  Pyrolysis produces little or no contaminating fumes and results in a stable form of carbon that can’t easily escape into the atmosphere.  Biochar is a very efficient way to convert carbon into a stable form.

Adding charred biomass to improve soil quality has been done for thousands of years.  Indigenous people in the Amazon added charcoal, food residue, and other waste to their soil.  When mixed with soil, biochar creates favorable conditions for root growth and microbial activities, which reduces greenhouse gas emissions. 

Last year, 125,000 tons of carbon dioxide were removed worldwide in the durable carbon market, which is a carbon credit marketplace for carbon removal.  About 93% of that was in the form of biochar. 

Biochar represents a value-added way to deal with agricultural waste and also to make use of dead trees in forests that should be removed to lower the risk of wildfires caused by the presence of all that dry tinder material. 

A bill to fund biochar research is pending before the Senate Agricultural Committee.  It is a rare example of bipartisan legislation.

Biochar is currently expensive to make in the US because large amounts of biomass must be shipped to one of the fewer than 50 small-scale production facilities in the country.   But with appropriate infrastructure, biochar could play an important role in efforts to sequester carbon and combat climate change.

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Biochar Is ‘Low-Hanging Fruit’ for Sequestering Carbon and Combating Climate Change

Photo, posted September 3, 2019, courtesy of Tracy Robillard / NRCS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon-Negative Concrete | Earth Wise

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Concrete is a mainstay of modern civilization.  The world produces more than 4 billion tons of it each year and the process requires high temperatures, mostly obtained by burning fossil fuels.  The chemical reactions that produce concrete also produce large amounts of carbon dioxide.  In all, cement production is responsible for about 8% of total global carbon emissions by human activities.

This situation is the impetus for a wide range of research activities aimed at reducing the environmental impact of concrete production.  Researchers at Washington State University have recently developed a way of making carbon-negative concrete: a recipe for concrete that absorbs large amounts of carbon dioxide.

There have been attempts in the past to add biochar to concrete.  Biochar is a type of charcoal made from organic waste that sucks up carbon dioxide from the air.  In earlier attempts, even adding 3% of biochar would dramatically reduce the strength of the concrete.

The WSU researchers found that treating biochar with concrete washout wastewater makes it possible to add much more biochar to concrete without reducing its strength.  Mixing it with biochar adds calcium, which induces the formation of the mineral calcite, which in turn strengthens the concrete.

The researchers were able to add up to 30% biochar to their cement mixture.  Within a month, the resultant concrete was comparable in strength to ordinary concrete.  But at the same time, the biochar was able to absorb up to 23% of its weight in carbon dioxide from the air.  The new concrete is potentially the most environmentally friendly concrete ever developed.

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Researchers develop carbon-negative concrete

Photo, posted January 31, 2012, courtesy of Michael J. Nevins / U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfires And Carbon

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This summer has been an unprecedented year for fires in the Arctic.  Major fires have burned throughout the Arctic in Russia, Canada, and Greenland.  In total these fires released 50 million tons of carbon dioxide in June alone, which is as much as Sweden emits in an entire year.

In an average year, wildfires around the world burn an area equivalent to the size of India and emit more carbon dioxide to the atmosphere than global road, rail, shipping and air transport combined.

Ordinarily, this is part of a natural cycle.  As vegetation in burned areas regrows, it draws CO2 back out of the atmosphere through photosynthesis.  This is part of the fire-recovery cycle, which can take less than a year in grasslands, but decades in forests.  But in Arctic or tropical peatlands, full recovery may not occur for centuries.

A recent study looked at and quantified the important role that charcoal plays in helping to compensate for carbon emissions from fires.  In wildfires, some of the vegetation is not consumed by burning, but instead is transformed to charcoal – referred to as pyrogenic carbon.   This carbon-rich material can be stored in soils and oceans over very long time periods.

Researchers have combined field studies, satellite data, and modelling to quantify the amount of carbon that is placed in storage in the form of charcoal.  Their results are that the production of pyrogenic carbon amounts to about 12% of the CO2 emissions from fires and can be considered a significant buffer for landscape fire emissions.

Charcoal does not represent a solution to the problem of increasingly intense wildfires, but it is important to take it into account in understanding what is happening.

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How wildfires trap carbon for centuries to millennia

Photo, posted August 17, 2018, courtesy of the Bureau of Land Management Oregon and Washington via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Pulling Carbon Out Of The Air

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The world is increasingly united in the desire to reduce carbon emissions into the atmosphere.  There is much emphasis on reducing and someday eliminating our use of fossil fuels, which is the main culprit in the situation we find ourselves in today.  More and more we are embracing the use of renewable energy sources to produce electricity and we are starting to slowly move away from internal combustion engines to power our cars.

[Read more…] about Pulling Carbon Out Of The Air

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