The formula CO2 stands for carbon dioxide, an odourless and colourless gas found in nature and generated by human activities such as the use of fossil fuels. CO2 is a greenhouse gas, meaning a gas that traps in the atmosphere part of the solar radiation reflected from the earth, thus causing global warming.
Interesting notes on CO2
- Along with other greenhouse gases – water vapour, nitrogen trioxide, nitrogen dioxide and methane – CO2 makes up for a tiny fraction of the earth’s atmosphere. These gases differ in their ability to trap heat and the time scale of their impacts;
- Greenhouse gases are crucial in determining the global average temperature. Without them, the earth’s temperature would be about 33°C lower. However, increasing emissions caused by human activities cause a harmful ‘overload’ of the greenhouse effect;
The atmospheric concentration of CO2 due to anthropogenic activities has increased exponentially over the past 170 years, causing a surge described by scientists as the ‘hockey stick’ after the anomalous direction taken by the graphs.
The primary source of CO2 emissions is fossil fuels. The combustion of oil, gas and coal releases huge quantities of carbon that had taken several thousand years to accumulate underground back into the atmosphere. These molecules bind to oxygen molecules in the atmosphere and give rise to CO2.
The good news is that there are ‘carbon sinks’ in nature that absorb much of our emissions through their natural functioning. It is estimated that terrestrial and oceanic ecosystems have absorbed almost half of anthropogenic CO2 emissions between 2010 and 2020.
The bad news is that these sinks have limits that we have far exceeded, thus increasing the concentration of CO2 in the atmosphere and damaging ecosystems in a vicious cycle that increasingly reduces their absorption capacity.
The scientific and climate governance community has agreed that 350 ppm (parts per million) is the ‘safe’ level of atmospheric concentration of carbon dioxide. This level was reached in the 1980s. Today, the concentration in our atmosphere is above 420 ppm. CO2 is the key parameter of the scientific reports and diplomatic agreements produced in major international fora. This does not mean that other greenhouse gases do not have a major impact on climate. To make the global emissions picture easier to read, a single metric, CO2-eq, which stands for ‘CO2 equivalent is adopted. In a nutshell, the quantities of other gases such as methane are converted to the equivalent quantity of carbon dioxide with the same global warming potential.
zeroCO2 and CO2
zeroCO2 develops reforestation projects that contribute to the absorption of great volumes of CO2 in the atmosphere through the natural life cycle of trees.