Carbon Storage and Sequestration, what are they exactly?

While often considered synonyms, Carbon Capture and Carbon Sequestration are discrete concepts.  Carbon Capture is the sum of the carbon sources stored by a forest, while Carbon Sequestration is its variation over time (Cantanzaro & D’Amato, 2019).

Carbon stored is stored in forests in five pools: Aboveground Biomass, live-belowground biomass, litter, deadwood, and soil organic matter (See Figure 1).  According to the Global Climate Observing System (GCOS, 2019), live Aboveground Biomass (ABG) is one of fifty-four essential climate variables due to its importance in the global Carbon Cycle (CC). It is difficult to measure on a finer scale because data are usually representative of large geographical extensions through the equatorial, tropical ecosystems. Accordingly, scientists have developed innovative methodologies and models to quantify the amount of carbon stored in ABG and other carbon pools in other regions of the world. 

Figure 1. Carbon pools stored in a forest.

Underlying the concepts of Carbon Capture, Carbon Storage is the all-important CC. According to the U.S. Geological Survey (USGS, 2022), the simplest way to quantify and map the CC is by identifying carbon-emitting sources and those that act as reservoirs. Carbon can be released into the atmosphere naturally (respiration of heterotrophic organisms, forest fires, and volcanic eruptions) or artificially (fossil fuel emissions, transportation, and agriculture). 5.5 billion tons of carbon from fossil fuels are released into the atmosphere each year. 60% remains in the atmosphere (University Corporation for Atmospheric Research, 2011), while the remainder is absorbed by carbon reservoirs (also defined as sinks)—natural areas that have the capacity to accumulate large quantities of carbon, including, wetlands, forests, soil, and the ocean. An infographic detailing the carbon cycle is presented in Figure 2. 

Figure 2. Carbon cycle.

 

References 

Catanzaro P., and A. D’Amato (2019). Forest Carbon: An essential natural solution for climate change. University of Vermont, USA.  

Global Climate Observing System (GCOS, 2019). Essential climate variables.  GCOS-WMO. https://ane4bf-datap1.s3.eu-west-1.amazonaws.com/wmod8_climatedata/s3fs-public/biomass_ecv_factsheet_201905.pdf?UIj2pnLviZJQEYAmaNuHOB3_fWsMjQoS.

University Corporation for Atmospheric Research (UCAR, 2011). Biogeochemical Cycles. https://scied.ucar.edu/learning-zone/earth-system/biogeochemical-cycles. 

U.S. Geological Survey (USGS, 2022). Carbon Cycle. https://www.usgs.gov/media/images/usgs-carbon-cycle.