So we’ve learnt about the greenhouse effect and that greenhouse gases are responsible for this process. Now then, what’s causing these greenhouse gases to increase?
The short answer? Humans. The long answer? Well, also humans, actually. But there is a bit more to it…
First of all, let’s take a closer look at the greenhouse gases. The term “greenhouse gases” is a generic term that refers to a group of gases found in the atmosphere that display heat-trapping properties. There are several different types of greenhouse gases, all of which are naturally found in our atmosphere (remember, the greenhouse effect is a natural process that keeps our Earth warm enough to support life). The problem is that we humans have increased the amount of these gases in the atmosphere drastically. The main greenhouse gases are:
Carbon dioxide (CO2):
emitted from: combustion (burning); this includes burning fossil fuels to produce energy
probably the most widely known greenhouse gas, CO2 is the most emitted greenhouse gas, and therefore has the biggest impact on global warming compared to all the other greenhouse gases
Methane (CH4):
emitted from: rotting (such as rotting waste in landfills), extracting fossil fuels, agriculture
did you know that cow burps emit over 104 million tonnes of methane each year?
Nitrous oxide (N2O):
emitted from: fertilisers, burning fossil fuels, treating sewage
Fluorinated gases (F-gases):
emitted from: refrigerators, aerosols, air conditioners
In 1985, a hole was discovered in the ozone layer of our atmosphere above Antarctica. It was quickly discovered that CFCs, a particularly harmful type of F-gas, were responsible for this depletion in ozone. In 1987, the Montreal Protocol was adopted, and as of 2023 has been signed by 197 countries to phase out the usage of CFCs. This treaty has been one of the most successful environmental actions in history.
There are also other types of greenhouse gases, such as water vapour and ozone, but they are found in much smaller amounts and do relatively less damage to our environment.
All of the greenhouse gases heat the planet in different amounts. The overall impact a greenhouse gas has on the warming of the planet is known as its “radiative forcing”, and it is measured based on how long it stays in the atmosphere, how much of it is found in the atmosphere, and how effectively it can trap heat. The stronger a greenhouse gases’ radiative forcing, the bigger its impact on global warming. The greenhouse gases listed above are actually ranked by their radiative forcing, meaning that carbon dioxide has the most impact on global warming while F-gases have the least.
Now we know that there is an excess amount of greenhouse gases in the atmosphere, which in turn is causing an excess of the greenhouse effect and driving global warming. But why are we emitting so many greenhouse gases to begin with? And why can’t we just stop emitting them? Find out in the next article on Climate change 101!
Credits:
Image - BioExplorer
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