Carbon dioxide and why it matters

Burning logs, woodchips and pellets releases carbon dioxide (CO2) that will remain in the atmosphere for decades. This may come as a surprise considering the mantra that energy wood is “carbon neutral”. So what exactly is going on?

Carbon is the fourth most abundant element in the universe and its ability to form complex molecules such as DNA and proteins is what makes life on Earth possible. Although our Planet is a closed system and therefore neither gains nor loses carbon, this doesn’t stop carbon from constantly moving about within this system. 

Most carbon is stored in rocks and sediments, with the remainder found in living organisms, the oceans and the atmosphere (the term “carbon sinks” is used to refer to places where carbon is stored outside the atmosphere). Plants and other living organisms constantly exchange carbon with the atmosphere when they breathe, photosynthesise and die. The oceans also absorb CO2 and have been growing increasingly acidic as a result. In the form of CO2 in the atmosphere it also helps control the Earth’s temperature. This is because CO2 is a heat-trapping gas, also known as a greenhouse gas (GHG). 

GHGs are emitted from natural processes such as volcanic eruptions, but also by burning fossil fuels and fromwildfires and log fires. They act like a blanket, preventing some heat from escaping the Earth out into space. This is a natural and important phenomenon because space is very cold and our Earth is constantly losing heat (infrared radiation), but Earth also receives heat in the form of sunlight (solar radiation). If more heat/energy enters Earth’s atmosphere than leaves it, then the atmosphere warms up. 

And the Earth is warming up thanks to the “thickening blanket” of human-produced (or anthropogenic) CO2. Although other GHGs are also involved, CO2 accounted for around 2/3 of the total heating influence of all anthropogenic GHGs in 2021. Data from ice cores reveal more CO2 in our atmosphere than at any point in the past 3 million years, with CO2 levels having increased by 50% in the last 200 years alone. The more we burn, the more we overshoot what carbon sinks can remove each year and the greater the concentration of atmospheric CO2.

And the hotter our Planet will get.