The Earth’s atmosphere consists of a variety of gases that wrap the entire surface of the planet. These gases, which are held in place by gravity, are made up of 78% nitrogen, 21% oxygen, 1% argon and trace amounts of a variety of other gases. It also contains a variable amount of water vapour, on average around 2%. The atmosphere is essential to all life on Earth. It provides oxygen for us to breathe, it filters out harmful light, and it stores the heat created by the sun. Without the atmosphere, the Earth would be a frozen, lifeless rock floating in space.
The planet’s ability to retain the sun’s heat depends primarily on the trace gases, more commonly known as greenhouse gases, contained within the atmosphere. This is made possible by the more complex molecular structure of the greenhouse gases which allows them to capture the heat created by the sun. This effectively creates a warm blanket protecting us from the cold of outer space. It also means higher concentrations of greenhouse gases in the atmosphere make the Earth warmer and lower concentrations of greenhouse gas in the atmosphere make the Earth cooler. Due to the burning of fossil fuels, and a variety of other human activities, concentrations of greenhouse gases in the atmosphere are increasing, which is resulting in progressively rising global temperatures. Of these gases, the most prominent is carbon dioxide, with all other gases measured in relation to the impact carbon dioxide has on our atmosphere.
Since the beginning of the industrial age, the amount of carbon dioxide equivalent in the atmosphere has increased from around 285 to 430 parts per million (ppm). This is the greatest amount of carbon dioxide equivalent in the atmosphere in nearly five million years. Incredibly though, if our greenhouse gas emissions continue to increase at the current rate, we could soon be locked into concentrations of more than 1,000 ppm. That is nearly a four-fold increase from pre-industrial levels and will almost certainly lead to a global temperature rise of some 4°C. While a temperature rise of this magnitude may not sound like a problem to many of us, the consequences would be cataclysmic.
To demonstrate just how serious things are, let’s assume that our emissions continue to increase at the current rate and see what scientists believe our planet is going to look like by the end of the century.
Image created by SUPER RADICAL LTD. Earth underlay sourced from ‘Station View of Tropical Storm Arthur‘, taken by NASA and reproduced in accordance with NASA guidelines. Satellite overlay sourced from ‘Hubble in Orbit‘, taken by the ESA/Hubble and reproduced under Creative Commons license CC BY 4.0. Stars underlay sourced from ‘Starry Night‘ taken by Kamil Porembiński, released on Flickr and reproduced under Creative Commons license CC BY-SA 2.0.
Barrels of oil equivalent is based on 1628.2 kWh of energy being contained within each barrel. Data sourced from Unit Juggler – 'Converter: Barrel of Oil Equivalent to Kilowatt-Hour' – unitjuggler.com.
The volume of one tonne of carbon dioxide is equivalent to 556.2 cubic metres. Sourced from International Carbon Bank and Exchange – 'CO2 Volume Calculation' – www.icbe.com.
For further information about any of the sources listed, please visit the ZERO EMISSION WORLD Works Cited page.