Carbon Sink

Carbon Sink

A carbon sink is a process or a reservoir that absorbs and stores carbon dioxide from the atmosphere. The primary aim of carbon sinks is to mitigate the effects of human-made carbon emissions on the Earth's climate. Carbon sinks play an important role in the global carbon cycle, which involves the exchange of carbon dioxide between the atmosphere, oceans, and the land.

Types of carbon sinks

Natural carbon sinks include oceans, forests, and soil. Oceans play a significant role in the global carbon cycle, as they are estimated to absorb about 25-30% of the carbon dioxide produced by human activities. Forests, on the other hand, are estimated to absorb and store about two billion tons of carbon dioxide per year. Soil also serves as a carbon sink, although the extent of this sink is less well understood. Soil, ocean and forests are the most absorbing factor for carbon sink in the world.

Soil absorbs around 25% of all carbon emissions each year. A large portion of this is stored in peatland or permafrost. Peatlands are a type of wetland that occur in almost every country worldwide. They cover only 3% of Earth's landmass, but store vast amounts of carbon twice as much as the world's forests.

Oceans are the main carbon sinks, absorbing up to 50% of CO2. Plankton, Coral, algae and fish are responsible for this capture. Phytoplankton are responsible for absorbing 25% of all carbon emissions. These microscopic marine algae and bacteria absorb as much carbon as all the trees and plants on land combined.

The world's forests absorb 2.6 billion tones of CO2 each year. Forests and plants grab carbon from the atmosphere to use in photosynthesis. Some of this carbon is transferred to soil when plants die and decompose.

Artificial carbon sinks are man-made structures that are designed to absorb and store carbon dioxide. For example, carbon capture and storage (CCS) technology is a form of artificial carbon sink. CCS involves capturing the carbon dioxide emissions from power plants or industrial processes and storing it in underground reservoirs. Another example of an artificial carbon sink is reforestation or the planting of new forests, which can absorb and store large amounts of carbon dioxide. For More about CCS Technology , Refer here .

Carbon sinks play a crucial role in mitigating the effects of climate change. By absorbing and storing carbon dioxide, they reduce the amount of this gas in the atmosphere, which is the main driver of global warming. However, the effectiveness of carbon sinks in reducing global carbon emissions is limited. For example, while forests can absorb large amounts of carbon dioxide, they also release carbon dioxide through processes such as decay, wildfires, and deforestation. Moreover, the capacity of carbon sinks to absorb and store carbon dioxide is finite, and as the levels of carbon dioxide in the atmosphere increase, the ability of carbon sinks to absorb and store this gas decreases.

In conclusion, carbon sinks play an important role in mitigating the effects of human-made carbon emissions on the Earth's climate. While they can effectively reduce the levels of carbon dioxide in the atmosphere, their effectiveness is limited, and their ability to absorb and store carbon dioxide decreases as atmospheric levels increase. Thus, it is important to find alternative methods to reduce carbon emissions and limit the impacts of climate change.

Carbon Capture Utilisation and Storage

 Carbon Capture Utilisation and Storage 

Carbon capture Utilization and storage (CCUS) is an attempt to remove carbon dioxide from the atmosphere after burning gas, oil, coal or biomass. The technology can capture the carbon and use it wisely whenever there are important ways to do so. This technology could play a diverse role in meeting global energy and climate goals.

Why carbon needs to stored ?

Carbon emissions have continued to grow at an average of 1 to 2% per year over the past 81 years. If this trend continues into 2050, we will reach a point where our emitted carbon has reached 60 billion metric tons. Across all these years, the carbon emission ranged from 4.25 billion tons to 37.12 billion tons—which is 873.5% in total! Can you imagine living without oxygen? The world would be filled with only Carbon Dioxide gas evolving around us - lots of environmental pollution, along with unpredictable climate changes and natural disasters could occur as a result。

To achieve a more stable and healthy environment, the United Nations has enacted several policies designed to reduce carbon emissions. These agreements were signed in Paris at the end of 2015, with the goal of bringing atmospheric levels of CO2 down to zero by 2050. This is known as "Net Zero" energy production - meaning that we would generate as much renewable energy as needed to offset our own emissions every year. It's an ambitious but achievable goal!

Are we stick with our goals and moving towards it ? Might be Yes ! Might be No !. We will discuss this in our upcoming articles.

Carbon Capture Utilization and Storage

Various Industries uses various technologies to capture the carbon. But the Foremost and commonly used technics are only two they are ,

• Point Source Carbon Capture
• Direct Air Capture

Point source carbon capture

Point source carbon capture is the process of capturing CO2 emissions before they are released into the atmosphere. It is a pre-emissive technology , that is the carbon is captured before the emission. The Flue gas is harnessed from the Factory chimney, its between 100-165 degrees. Since the temperature is very high it needs to be cool down to 30 degrees. This process happens in a direct contact cooler, the temperature is reduced and Caustic soda (NaOH) is added to remove sulfur dioxide and hydrochloric acid from the flue gas and the cooled flue gas then goes to the bottom of the absorber. Then the solvent is injected in the other side of the absorber. The CO2 molecules in the flue gas react with solvent. The solvent which use for carbon capture is Mono ethanol amine(MEA). Mono ethanol amine has the tendency to combine with carbon , that is the carbon is easily attracted and combines with Mono ethanol amine. The rest of the flue gas without the content of CO2 it again pass back to the chimney. This MEA and CO2 combination is termed as rich amine solution, consists of only carbon and MEA. Then this rich amine is pumped into a desorber where the mixture is heated to about 120 degrees .This thermal cracking breaks the bond between the MEA and CO2. Then the CO2 is compressed for utilization and storage.

pictorial representation of point source carbon capture

Direct Air Capture(DAC)

Direct Air Capture is  a technology that uses the chemical reaction to pull carbon dioxide out of the air. It is a post-emissive technology that is the carbon is captured after the emission process. The key advantage of this technology is it can be placed anywhere, irrespective of industries. If some area is highly polluted we can simply place this technology there. It is not mandatory to place this technology in nearby Industries.

Big Fans are used to suck large amount of polluted air directly out of the atmosphere. Behind the fan, the carbon absorbent material is placed to absorb the carbon. In DAC, PVC sheets are used to absorb the carbon. PVC sheets acts as a filter too. Every single surface inside the stack is wetted with carbon dioxide absorbing solution. In most cases, Amine solution is used. Air containing CO2 flows over the surfaces and when CO2 molecules encounter the liquid then converted into carbonate. The Geometry of the packing material ensures that much of the liquid is possible is exposed to the passing air. It also disturbs the flow creating turbulence , so most of the air streaming through actually makes contact with the solution. The net result, the Carbon dioxide is trapped in solution for further processing.

        Scenarios behind the fan

                  pictorial representation of direct air capture

Storage and Utilization

When comes to storage , both Point source method and Direct Air capture method stores in a similar way. The Captured CO2 is sent to the reservoir/ sea beds through pipelines, it can be stored for several years and after that time period these CO2 gas converts into minerals. This is where the CO2 is well utilized.

In order to produce synthetic fuels, captured carbon must be stored in special equipment. Once this carbon is captured, it can then be used in food processing or combined with hydrogen to create synthetic fuel. In a transition towards net-zero emissions, the use of CO2 for producing synthetic fuel will increasingly require capture from sustainable bioenergy sources or from the atmosphere. In Industry applications, Captured CO2 is used as an enhanced oil recovery method



Do you ever wonder why carbon is the most important factor for climate change? After all, oxygen and nitrogen make up nearly 99% of the atmosphere. So why are these two elements not considered as important when it comes to climate change?

 Click here to find the answers

Why Carbon is important for Stable Environment ?

Carbon Cycle : 

The carbon cycle is a term for the biological process by which carbon moves from one form to another in Earth's atmosphere. Humans and animals inhale oxygen, but trees inhale carbon dioxide. Thus, all plants, humans and animals are part of this cycle.

Carbon dioxide: 

                         Carbon dioxide is an important gas for life on Earth. It is essential to maintaining a protective blanket around the planet (the Earth's atmosphere).

So why carbon dioxide is important to earth's atmosphere?

The key parameter is Carbon dioxide is one of the primary green house gases on Earth. Before going on to the topic we shall have a short discussion about green house gas.

Green house gases are gases in the earth's atmosphere that traps heat. As we know the earth is located at a distance of 150 million km (approx.) from the sun. The earth naturally have a protective layer which acts as shield outside the surface. This layer is termed as ozone layer that acts as shield outside its surface. This layer protects us from harmful ultraviolet rays from space and cosmic rays within our solar system. If this protective layer gets destroyed due to increased amounts of solar radiation reaching Earth. This sun rays will have  a direct impact on Earth . Some of the examples are the rays can directly affect the human and these rays are responsible to decrease the human Immune system and there might be a high probability of increasing Cancer  in humans . These rays can affect the environment by melting the glaciers. So then there will be increase in Sea level and starts with climate change. These are only few examples. The atmosphere contains several different types of greenhouse gases, including water vapor, carbon dioxide (CO2), methane (CH4) and ozone (O3). These gases absorb infrared radiation emitted by Earth's surface and re-radiate it at longer wavelengths than would be possible for them if exposed to vacuum; this is what makes CO2 a greenhouse gas. 

These are the fundamentals about our mother earth and green house gas effects.

So why Carbon ?

Carbon dioxide is one of the most important greenhouse gases on Earth. The atmosphere contains many other gases besides carbon dioxide, but it accounts for only about 0.039 percent of the total mass of air in our planet's atmosphere.

                                                        

                         All materials on the planet are composed of carbon . Even in human bodies, DNA and proteins are long, basically infinite polymers based on carbon. Fats and sugars are based on carbon. Most molecules cells use to communicate with each other are based on carbon. The most important molecule in cells is glucose, and most of the signaling that goes on between cells occurs via organic molecules called hormones that are made from glucose.

Carbon, the second most abundant element in the universe and first major component of living organisms, can be divided into three pure materials: graphite, coal and diamonds. These materials have an impact on human life in a variety of ways. Graphite is used in pencil leads, lubricants and polishes, lamps and batteries as well as in electric motors and some electronic devices. Coal is the main source of thermal power plants; thus electricity we use is indirect from these plants. Diamonds are used for jewelry but also for scientific research because their hardness makes them ideal for cutting and polishing equipment. Even though all three purest carbons are not alive, human usage with these materials is very high due to their variety of uses.

Carbon has a natural affinity for forming bonds with a wide variety of elements. In this drug (Furosemide), carbon is connected to other carbons, oxygen, chlorine, nitrous oxide and sulfur. Furosemide is a medical drug which is used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It may also be used for the treatment of high blood pressure.

a. Furosemide Structure (Carbon composition)

                                    

Carbon can also bond in different ways as 

1. Stable

2. Reactive

3. Tetrahedral

4. Rings

5. Chair

                          

                                                             b. Carbon bonding types 

Carbon, in its natural form, is a very light and malleable material. Greenhouse gases like carbon dioxide and methane are important contributors to the greenhouse effect because they can trap heat from the sun.

Why Carbon ? Why not Oxygen or Nitrogen ?: 

Did you realize why carbon is the most important factor for climate change, given the fact that oxygen and nitrogen play a much lesser role? 

Apart from all the gases, only Greenhouse gas (carbon dioxide) can absorb heat radiating from earth's surface and release in all directions - which includes back towards earth surface. Without carbon dioxide earth's natural green house effect would be too weak to keep the Average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, peoples are supercharging the natural green house effect, causing global temperature to rise. According to the observation of National Oceanic and Atmospheric Administration (NOAA) global monitoring lab, in 2021 Carbon dioxide alone was responsible for above two thirds of total heating influence of all human-produced green house gases. 

Another reason carbon dioxide is important in Earth's system is that it dissolves into the ocean like the Fizz in a can of soda . It reacts with water molecules, producing carbonic acid which lowers the ocean pH level and results in Ocean Acidification.

 

The data was collected and monitored for last 100 years from the above graph and as per the Global Carbon report, in 2022 the carbon emission is 37.5 billion tones from all over the world. It is one percent more than 2021. The conclusion from these facts that whenever there is high emission of Carbon it directly proportional to increase in Global temperature rise.  So, the carbon play is very high important to environment.