Carbon is literally everywhere – it’s part of us, it’s in what we eat, it’s in our breath when we exhale, it’s in our atmosphere and it is in the fuel we commonly use to heat our homes and power our cars.

It is the basis of all life on earth and it is even part of our genes, which dictate the color of our eyes or how tall we are!

We hear a lot about carbon now, because of its role as a component of carbon dioxide or CO2. Carbon dioxide is a gas that occurs in our atmosphere, produced when animals and people respire (breathe) and it is released when fuels like coal and oil are burned to provide heat and power.

People are talking about carbon dioxide now as it is an important greenhouse gas. This means it plays a role in keeping the earth warm, which allows the world as we know it to exist.

Over the last few hundred years, the amount of carbon dioxide in our atmosphere has increased, largely due to the activity of people on the planet and now the planet is going through a period of quicker climate change, which experts agree is because of this increase in greenhouse gas levels. This is bad for the planet.

It is the basis of all life on earth and it is even part of our genes

There are other greenhouse gases too, such as methane, which I wrote about before, and a gas called nitrous oxide, which is released from nitrogen fertilisers, animal manures and other sources.

One of the key laws of physics states that in a ‘closed system’ matter can not be created or destroyed, ‘but it can be transformed from one form to another’. The earth and its atmosphere are a closed system, so the amount of carbon in the system does not change, but the location and the form in which it is stored is constantly changing. This is known as the carbon cycle.

So, if you have potatoes, carrots and beef for your dinner tonight, all these foods contain carbon – that is how we get energy from food. But a few weeks or months ago, that carbon in your food was carbon dioxide in the atmosphere. And when your body utilizes the energy in the food, you will exhale carbon dioxide back into the atmosphere and the cycle continues.

Sink or source

On earth and in the oceans, there are a number of places where carbon is stored, such as in rocks, soils (especially peat), in living organisms like animals and plants and also in fossil fuels.

These different stores are constantly changing – sometimes carbon is added to the store and in that case, it is referred to as a carbon sink. For example, a growing forest is a carbon sink because the trees are taking carbon dioxide from the atmosphere and converting it into wood.

In other cases, when carbon is being released from a carbon store, it becomes a carbon source, like when we take oil from the ground and burn it to produce heat or to drive our cars.

Governments and people all over the world are trying to slow down the rate at which carbon dioxide is being released from carbon stores. We see this every day with electric cars, or wind turbines to generate electricity. The focus here is reducing the amount of fossil fuels being used. There are also efforts to remove carbon dioxide from the atmosphere and one of the best ways to do this is through growing plants like trees, hedges and grass.

These plants take the carbon dioxide from the atmosphere and trap it in their roots, stems and leaves. Overtime, some of this carbon is transformed into soil carbon.

This process is known as carbon sequestration. Such capture will have a very important role to play in helping Ireland and the world reduce the amount of carbon dioxide in the atmosphere.

Farming in the cycle

Farming is at the centre of the carbon cycle. When grass grows, carbon dioxide is taken from the atmosphere and converted into leaves, stems and roots. Animals like cows and sheep then eat the grass and convert it into meat and milk for people to eat.

But not all the grass cows and sheep eat is converted to meat and milk, some is pooped back out onto the grass and supports the growth of new grass, but it is also used as a food source for microorganisms living in the soil, which over time help to convert some of the carbon in the poo into soil carbon.

Did you know that soils which are used to grow grass have more carbon stored within them than soils which are used to grow crops? Also, some of the carbon in the grass eaten is belched out by the cows as methane gas.

When grass grows, carbon dioxide is taken from the atmosphere and converted into leaves, stems and roots

We also have carbon dioxide capture in hedges, trees and woodlands growing on farms. This carbon remains within the trees and hedges until they are cut and is an important store of carbon too.

Perhaps one of the most important carbon stores in the world are our peat soils or bogs in Ireland. These peatlands have some of the highest carbon stores found anywhere in the world, but only when they are wet.

When these peatlands are drained, they become a source of carbon loss, so now the Government are looking at giving farmers money to rewet these peatlands, so they can once again become important carbon stores. This is going to be difficult, because when the peatlands are rewetted, they become less suitable for the farming activity that is currently taking place there.

Carbon is everywhere, it is part of who we are and the key to life on earth, but we need to be careful how we use it and how we manage it, to keep the atmosphere in a state that will allow the world to continue to be a suitable place for us to live.

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