The climate crisis is a big enough challenge as it is, without having to unpick the lingo. Our jargon-busting guide is on hand to help you feel informed, empowered – and able to tell your carbon dioxide from your greenhouse gases. Plus, what better time to brush up than while you’re stuck at home?
Carbon, just like love, is all around...because, put simply, we’re all mostly made of this stuff. The same goes for animals, plants, trees, and soil.
Carbon is a chemical element, the sixth most abundant on the planet. Its pure forms include diamond and graphite, and when combined with other elements it forms molecules. It’s these carbon-based molecules that are within us all. Every cell in our body contains carbon because it helps us function. We use it to make proteins, carbs, and fats.
In this context, carbon’s far from a dirty word! But when we talk about it in terms of global warming – as in ‘carbon footprint’ or ‘carbon emissions’ – what we actually mean is slightly different.
When people mention ‘carbon’ in the context of the climate crisis, they’re usually referring to a particular form of carbon - carbon dioxide. And too much carbon dioxide isn’t a good thing. Want to know why? Read on...
Carbon Dioxide (CO₂)
This is a gas formed when one atom of carbon joins with 2 atoms of oxygen (the bit we all remember from school).
Along with all living things, we emit CO₂ when we breathe. It makes up about 0.04% of our atmosphere here on earth. Doesn’t sound like much, does it? But even though it’s a small proportion of our air, CO₂ does a very important job. It acts like a blanket, trapping heat from the earth and keeping the earth warm enough for us humans (and every other living creature) to live here. This is called the ‘greenhouse effect’ because it is just like a greenhouse - sunshine goes in, gets trapped, and it stays warm inside. So far so good.
So why does everyone talk about CO₂ like it’s a bad thing? Carbon dioxide only becomes the bad guy when we release too much of it. Right now, by cutting down trees that absorb CO₂, while at the same time burning fossil fuels to create energy, we humans are letting CO₂ levels in the atmosphere get seriously out of balance. And once CO₂ gets released into the atmosphere, it stays there for a very long time. Over the last few decades, we’ve added CO₂ to the atmosphere at such a rate (on average, 1.5% a year for the past decade) that the earth’s ‘blanket’ is getting thicker and the world is heating up. We call this ‘global warming' - and that’s what is causing our climate to change more rapidly than it has ever done before in living history.
Greenhouse gases (GHGs)
CO₂ isn’t the only gas that has this ‘greenhouse effect’ - there are a few other gases too – the main ones being water vapour, methane (CH4), nitrous oxide (N2O) and ozone. And we’re releasing many of these into the air at a faster rate too. According to the Mauna Loa observatory data, the concentration of climate-heating GHGs has been steadily rising year after year. Since the start of the industrial revolution, the planet has warmed up about 1°C. So if we don’t act fast, the world could heat up by as much as 6oC this century!
Even though there are a few GHGs contributing to global heating, you’ll hear about ‘carbon’ (meaning carbon dioxide) the most often. This is because CO₂ is the gas that we release most from our human activities, like burning fossil fuels. What’s more, to make it easier to track how all these different GHGs are contributing to global heating, scientists measure the emission of all these gases using a unit that is catchily named ‘carbon dioxide equivalent’ (CO2e), which sounds much nicer when it’s shortened to just ‘carbon’.
Speaking of which...
Carbon Dioxide Equivalent (CO2e)
It might sound complicated, but it’s actually an easy way of measuring and comparing the various GHGs and expressing them in one common unit.
Different GHGs stay in the atmosphere for different lengths of time, and absorb different amounts of heat. So they have different impacts on how much they warm up the earth. But by saying how much carbon dioxide you would need to cause the equivalent amount of warming, you can get an idea of each GHG’s relative impact.
For example, 1kg of methane released causes 25 times more global warming than 1kg of CO2 over a 100 year period. This means methane has a CO2e of 25.
Want to learn more about carbon? We hear you – just go here.
And do you fancy some planet-friendly lockdown activities? Read this.