“Carbon sequestration” doesn’t exactly roll off your tongue or come up in day-to-day conversations – at least not for most of us. But perhaps it’s time more of us became aware of carbon sequestration and its role in controlling or deferring the impact of global warming.
Climate change is a top concern of individuals, environmentalists, scientists, businesses committed to green initiatives, and organizations too numerous to mention. How many allude to carbon sequestration (CS) as a major concern?
CS does present opportunities to reduce the accumulation of greenhouse gases and atmospheric damage from burning fossil fuels.
So What Is Carbon Sequestration?
CS refers to the capture and storage of carbon forms including carbon dioxide as a proposed means to alleviate global warming. In nature, carbon sequestration can be observed in chemical, physical, and biological processes.
For an example of naturally occurring sequestration, we need to look no further than the trees of a forest. Trees take in carbon dioxide and hold it as a natural carbon sink (more on carbon sinks below) – unless the tree burns or dies, releasing its carbon biomass. Oceans also absorb CO2 from the atmosphere.
Nature’s carbon cycle has performed well for millions of years, until humanity came along with industrial progress that threw everything out of balance.
Additional CS through artificial means supplements natural sequestration. Emissions such as CO2 from manufacturing and other industrial facilities can be transitioned to subsurface storage including reservoirs, depleted oil fields, and ocean waters. The intent is to reduce the impact of emissions into the atmosphere that would otherwise accelerate climate change.
Artificial methods of carbon sequestration include:
- Reforestation – Replacing trees that have been stripped by timber harvesting restores the carbon absorption process, although it takes a great deal of time for these trees to mature into effective carbon “sponges.”
- Ocean deposits – Capturing CO2 and then injecting it into the oceans’ depths is another way to store excess carbon that has been generated by businesses and power plants. In theory, the CO2 will be diluted and absorbed by the waters. Some scientists question the potential impact on marine life with this approach.
- Underground sequestration – This involves essentially burying captured carbon below ground in areas known to be rich in such geological elements as calcium, where the CO2 can harmlessly combine with calcium to form limestone.
Carbon Sinks – How They Factor into Carbon Sequestration
Carbon sinks are naturally occurring or artificially created storage points for carbon-containing elements that include carbon dioxide. Carbon sinks may store carbon for the long-term – even indefinitely.
In nature, good examples of carbon sinks are:
- Trees and other plants – they absorb carbon dioxide, incorporating it into their carbon biomass
- Oceans – one of the largest natural carbon sinks
- Soil – carbon is also absorbed into the Earth’s soil, giving soil a carbon content higher than plants or the atmosphere
Artificial carbon sinks are created for man-made sequestration, utilizing various techniques. Some methods are still under evaluation for effectiveness and environmental impact, such as ocean injection.
Large-scale projects in mineral sequestration are being undertaken that create carbon sinks in geological areas rich in magnesium. This generates magnesium carbonate much more rapidly than this occurs in nature. The intention is to provide useful, reusable products without releasing the carbons into the atmosphere, removing them from a damaging carbon cycle.
This process of carbon sinks removing carbon dioxide from the environment is the process of carbon sequestration.
Why Are Carbon and Carbon Sequestration Important?
Carbon is the essential component of all life on Earth, from the least complex plant life to the human body. Carbon has the ability to combine with other compounds and elements to form a wide array of other materials. Living things contain nearly 10 million carbon-based compounds.
It is this very property of carbon that makes carbon sequestration occur in nature, and that makes it possible by artificial means.
Hydrocarbons are mainly composed of hydrogen and carbon, providing the basis for the fossil fuels we rely on. As carbon-based elements, they consist of decomposed and fossilized plants or other organic material.
This illustrates the importance of implementing artificial carbon sequestration properly to alleviate irreversible damage to the environment.
Will Carbon Sequestration Persevere?
The US Geological Survey (USGS) offers insight into the process of sequestration, both natural and artificial:
- Former Secretary of the Interior Sally Jewell reported that in the Eastern US, forests, wetlands, and farms are effectively contributing to a reduction in greenhouse gasses that cause climate change.
- New methods of deep groundwater sampling have created a more accurate way to evaluate the effectiveness of sequestration.
- A study published through the USGS alludes to the importance of monitoring sequestration, risk assessment, storage effectiveness, and the capability to verify carbon content.
Other factors pointed out by the USGS indicate potential issues with natural CS such as methane gas emissions from wetland carbon sinks that reduce the effectiveness of their sequestration properties.
Although natural carbon sequestration has been occurring since life began on Earth, the effectiveness and impact of artificial sequestration will be measured and evaluated over time.
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