Global warming explained
Since we are constantly receiving energy from the sun, how isn’t our planet constantly getting warmer?
The sun radiates energy towards Earth, but every planet has its own radiation and our planet is not an exception. This might not seem evident at first sight since Earth’s radiations are in the infrared wavelength. Meaning that they are invisible to humans. So, planet earth has a way of cooling off and that way is to emit infrared radiation into space. There is a balance between how much energy is received from the sun and how much energy is emitted into space. So that’s how our planet reaches an equilibrium temperature that turns our planet into a livable environment.
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Did you know greenhouse gases are actually good for us?
Yes, no kidding! Greenhouse gases are not that bad. Without greenhouse gases, planet earth would have an average temperature of -18°C and be inhabitable for humans. So yes, we are alive thanks to greenhouse gases. Why we call them greenhouse gases is due to the fact that they turn Earth into a huge greenhouse! The greenhouse gases are transparent to sun rays but are opaque to the infrared radiation from Earth. So they let the sun rays through and absorb/reflect a portion of the outgoing infrared emissions from Earth. This will prevent a portion of the heat from escaping and as a consequence, it will augment the planet’s equilibrium temperature.
Did you know water is a greenhouse gas? And the most important one at that?
Yes, greenhouse gas is not caused only by CO2. Water is a natural greenhouse gas and is responsible for about 66-85% of the total greenhouse effect on Earth (including clouds) while CO2 is only responsible for 9%-26%. The water vapor that exists in the atmosphere is very important for keeping the temperature equilibrium of planet Earth.
So what is all the fuzz about global warming and greenhouse gasses?
Anthropogenic (human-made) greenhouse gases are responsible for the well-known phenomenon called Global Warming. On this list, we can name carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Technically, when we burn fuels and emit greenhouse gases into the atmosphere, it will cause the greenhouse effect to become stronger than its natural state. In consequence, more heat will be prevented from leaving the planet and the temperature of the planet will rise until it reaches a new equilibrium that is higher than the previous one.
But water is mostly responsible for the greenhouse effect. Why do we care so much about CO2?
It is true that water is the main contributor to the greenhouse effect, but it is not the cause of global warming. CO2, CH4, and N2O that we produce in our human activities will slightly increase the greenhouse effect and make the planet slightly warmer. As the planet gets warmer the amount of water vapour in the atmosphere will increase and further intensify the greenhouse effect. Therefore, there will be a forcing effect that will warm the planet even more. This cycle will keep happening and the planet will get warmer and warmer until it reaches a new equilibrium with a higher temperature.
It’s like a ball sitting at the top of a hill in equilibrium. Once you disturb its equilibrium it will start going downhill.
Also, water does not stay long in the atmosphere. Its short residency time does not allow enough time to contribute to global temperature change. There is large inertia in the global warming effect. It takes years for us to see the warming effect of the greenhouse gasses we have produced today. As water does not have a long residency time it can not have much impact on its own in global warming.
Ask your questions, doubts, and thoughts relating to global warming below and I will add them to this page! 🙂
