data jungle adventures

A projected increase of 1.1% from 2022 levels of fossil fuels emissions is foreseen as the result of a new record reaching highs in 2023 as per the annual Global Carbon Budget. A new record to hit, but probably one that we cannot be proud of.

“…fossil fuel emissions will once more reach record highs in 2023”

DeBriefed COP28 UAE

One of the factors to fight climate change is the process of capturing and storing greenhouse gas emissions. Is that counter-intuitive in anyway? What is carbon storage? How is it estimated? And which project can we consider as an example to estimate the amount of carbon stored?

Define the definitions

Carbon Capture and Storage (CCS) is one of the important geo-engineering solutions for climate change. It is the capturing, transportation, and storing of greenhouse gas emissions from different sources that produce those gases. For instance, burning fossil fuels (gas, oil, coal), volcanic eruptions, energy-intensive industries, gas fields, etc. The destination of carbon storage is usually forests and their soil.

It is important to mention the difference between carbon sequestration and carbon storage. The first can be a natural or artificial process where carbon dioxide is removed from the atmosphere and held in solid or liquid form. It is the capture and secure storage of carbon that would otherwise remain in the atmosphere.

As for carbon storage, it builds plant structures by converting glucose in plants into cellulose and lignin. Carbon in forests is stored mostly in the soils and the above ground living biomass. This is the difference between above-ground carbon and below-ground carbon.

In all, we probably can say that carbon sequestration is the process of capturing and storing carbon in general. The fact that it can be natural or artificial turn the attention to carbon storage, that is effectively, part of carbon sequestration yet it is a man made part.

Storage: how and how much

How is the carbon stored by human effort and how can we estimate the quantity of carbon being stored in an area or another? And how much carbon do we produce during carbon storage projects?

The CCS process includes several key elements: point sources of excessive CO2 and greenhouse gases production (factories, locaitons of burning fossil fuels, etc.), pipelines, and wells. Carbon is captured at source points of pollution. It is then transported through the pipelines underground and offshore to be injected at the end into wells of former oil or gas fields or deep aquifers. Australia, Norway, the United States, Indonesia, UK, and the Netherlands lead projects of carbon capture and storage.

As for carbon storage in forest, plants, and soil, here is a deeper dive into this area. In forests, carbon can be stored under-ground and above-ground. Trees contain up to half the carbon in a forest. Thus making the management of carbon above-ground easier than that under-ground.

Trees contain up to half the carbon in a forest.

psu.edu

There are several methods to estimate the amount of carbon stored in ecosystems of forests and soils for example. Here is a quick overview of these methods’ list. Walong Sun and Xuehua Liu list vegetation carbon estimation methods and soil carbon estimation methods. The first include inventory-based estimation, satellite-based estimation, and process-based estimation As for the soil carbon storage estimation, it can happen based on either the soil type method, the life belt method, the soil carbon empirical modeling method, or the process-based modeling method. Here is a short explanation for two of each category’s method.

1. inventory-based estimation of vegetation carbon: four methods here estimate carbon storage based on inventory data of several variables. Some of these variables are: average carbon density, forest area, stand volume, diameter at breast height, and carbon content rate. The four methods are: average biomass method, volume-derived, biomass regression equation, and conversion factor continuous method.
2. satellite-based estimation of vegetation carbon: according to Walong Sun et al., three types of datasets using remote sensing technologies can be used for vegetation estimation of carbon storage: optical remote sensing data, synthetic aperture radar satellite data (SAR), and Lidar data.
3. soil type method for soil carbon estimation: three variables are needed for this method. taxonomic unit definition, soil type delineation and sampling. Based on different soil type sampling data, we obtain soil carbon storage of taxonomic unit, then we calculate regional soil organic carbon storage according to soil type map.
4. life belt method for soil carbon estimation: this method calculates the regional soil organic storage by multiplying soil organic carbon density of different life belts or ecosystems with their areas.

All these methods and others deserve a more in-depth review for a deeper understanding of the estimation process. Meanwhile, we can estimate an area’s storage carbon based on a simple method.

Project-example

In an attempt to estimate carbon storage for an area, we can build a rough estimation for an area based on a the following two simple methods:

1. The first method: it estimates the tonnes of carbon storage per hectare per weather for vegetation and soil. In desert and semi-deserts climates, vegetation is estimated to store 2 tonnes of carbon per hectares and soil provides an estimation of 42 tonnes of carbon per hectare.
   Meaning, in an area of 6.5 km2 (650 hectares) with 1.2 km2 (120 hectares) of vegetation and soil, the total estimated carbon storage is = (120 * 2) + (120*42) = 240 + 5,040 = 5,280 tonnes.

2. Another simple method provides en estimation of carbon in 4 steps:

• measure 1.3 m up the tree trunk
• at 1.3 m, measure the circumference
• estimate the dry weight based on this table
• half the dry weight is carbon

For example, an Acacia tree with a circumference of 50 cm:

• the dry weight of this tree is 106 kg (reference)
• carbon = dry weight/2 = 106/2 = 53 kg of carbon

Those high-level estimations assume that carbon is not only stored in the stems and ignores leaves, branches, roots, soil, ground cover, dead and fallen leaves.

Last words

If you want to invest in Carbon credits, then the 5,280 tonnes of carbon is equivalent to 5,280 carbon credits (with 1 Carbon credit = 1 tonne of Carbon emissions).

Would you plant a tree today to trade for carbon credits tomorrow?