In short, greenhouse gases (GHG) trap heat in the atmosphere and warm up the earth. It’s important to note that they’re not all bad though – if it wasn’t for greenhouse gases holding in heat from the sun, the earth wouldn’t be kept warm and we’d all be living on an ice block. The difficulty comes when we have too much greenhouse gas...
Too much greenhouse gas makes the world too warm and in doing so upsets eco-systems, weather patterns, ocean currents and essentially messes with life on earth as we know it.
The most abundant greenhouse gases in the atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbons (CFCs). Here is a brief overview of these prominent greenhouse gases:
- Water vapour – water in its gaseous state – heats energy in the air and accounts for somewhere between 36 per cent and 85 per cent of the earth’s greenhouse effect (depending how many clouds are about). Unlike other GHGs, water vapour doesn’t hang around, becoming rain or snow only days or even hours after it has been generated through evaporation.
- Carbon dioxide (CO2) perpetuates the earth’s warming effect and has scientists biting their fingernails, since its warming influence is larger than all the other greenhouse gases combined (thanks to its long atmospheric life of up to 200 years). CO2 accounts for over three-quarters of man-made GHGs and is predominantly released from fossil-fuel burning – meaning it has a pretty big part to play in global warming.
- Methane is actually far more potent than CO2 – around 25 times more. It is released from natural sources like wetlands, but also a huge amount comes from cows burping and, to a lesser extent, farting. In fact, rearing cows is often said to produce more greenhouse gases than having that car in your driveway. We can’t control cows’ belching habits, but it does raise questions about the role that agriculture has to play in climate change.
- Nitrous oxide is super effective at trapping heat (200-300 times more so than CO2), but makes up only a small part of the atmosphere. Major contributors to its increase are believed to be nitrogen-based fertilisers and sewage treatment plants.
- The ozone is both a natural part of the atmosphere and man-made through air pollution. Its radiative force is about 1,000 times as strong as CO2, but since it’s being created and destroyed all the time, it has a short shelf life and its global warming potential is far less.
- Chlorofluorocarbons (CFCs) were commonly found in deodorant and other spray cans until the 1970s, when it was decided that making a hole in the earth’s ozone layer was not a good thing. Environmental campaigners did a great job at ushering in a much more ozone-friendly alternative: HFCs (hydrofluorocarbons), which still contribute to the warming effect, albeit in a smaller way.
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Read more from our content series as we explore everything you need to know about climate change (but were too afraid to ask) in the run up to Paris 2015!