Biological carbon sequestration

The National Weekender
ENVIRONMENT

By GODFRIED ANGI
ABOUT 25 percent of global carbon emissions are captured by plant-rich landscapes such as forests, grasslands and rangelands. When leaves and branches fall off plants or when plants die, the carbon stored either releases into the atmosphere or is transferred into the soil. Wildfires and human activities like deforestation can contribute to the diminishment of forests as a carbon sink.
Grasslands
While forests are commonly credited as important carbon sinks, California’s majestic green giants are serving more as carbon sources due to rising temperatures and impact of drought and wildfires in recent years.
Grasslands and rangelands are more reliable than forests in modern-day California mainly because they don’t get hit as hard as forests by droughts and wildfires, according to research from the University of California, Davis. Unlike trees, grasslands sequester most of their carbon underground. When they burn, the carbon stays fixed in the roots and soil instead of in leaves and woody biomass. Forests have the ability to store more carbon, but in unstable conditions due to climate change, grasslands stand more resilient.
Ranchland carbon sequestration
Ranches with their large swaths of grazing grasses have the ability to store carbon in their soil. As livestock graze, they encourage plants to grow and capture carbon dioxide from the atmosphere
Plants feed carbon to microorganisms living in the soil, benefiting plant growth, drought resistance and the climate
And so the nutrients that came from the animals are more readily available, not only for the plants but also for all the soil microbes. And so that just kind of creates more activity and in theory more carbon sequestration. Ranchlands can potentially sequester up to 330 million metric ones of carbon dioxide in the soil
Geological carbon sequestration
Geological carbon sequestration is the process of storing carbon dioxide in underground geologic formations, or rocks. Typically, carbon dioxide is captured from an industrial source, such as steel or cement production, or an energy-related source, such as a power plant or natural gas processing facility and injected into porous rocks for long-term storage.
Carbon capture and storage can allow the use of fossil fuels until another energy source is introduced on a large scale.
Technological Carbon Sequestration
Scientists are exploring new ways to remove and store carbon from the atmosphere using innovative technologies. Researchers are also starting to look beyond removal of carbon dioxide and are now looking at more ways it can be used as a resource.
Graphene production
The use of carbon dioxide as a raw material to produce graphene, a technological material. Graphene is used to create screens for smart phones and other tech devices. Graphene production is limited to specific industries but is an example of how carbon dioxide can be used as a resource and a solution in reducing emissions from the atmosphere.
Direct air capture (DAC)
A means by which to capture carbon directly from the air using advanced technology plants. However, this process is energy intensive and expensive, ranging from $500-$800 per ton of carbon removed. While the techniques such as direct air capture can be effective, they are still too costly to implement on a mass scale.
Engineered molecules
Scientists are engineering molecules that can change shape by creating new kinds of compounds capable of singling out and capturing carbon dioxide from the air. The engineered molecules act as a filter, only attracting the element it was engineered to seek.
Impacts of carbon sequestration
About 25 percent of our carbon emissions have historically been captured by Earth’s forests, farms and grasslands. Scientists and land managers are working to keep landscapes vegetated and soil hydrated for plants to grow and sequester carbon.
As much as 30 percent of the carbon dioxide we emit from burning fossils fuels is absorbed by the upper layer of the ocean. But this raises the water’s acidity, and ocean acidification makes it harder for marine animals to build their shells. Scientists and the fishing industry are taking proactive steps to monitor the changes from carbon sequestration and adapt fishing practices.
In the next article we will discuss the carbon cycle

  • Godfried Angi is the principal scientist at Yeyue Environmental Services