- Venus is too hot, Mars is too cold but Earth is just right
- Earth’s average temperature sits between the boiling and freezing temperatures of water.
- This makes it ideal for life
Insulating gas blanket
- Earth’s “perfect” surface temperature for life is often thought to be because of it’s orbit distance from the Sun. This is only part of the story.
- All of the different components of Earth’s climate system (atmosphere, hydrosphere, lithosphere and living things) absorb energy from the sun.
- None of them absorb 100% of the available energy. A lot of the energy is reflected instead of being absorbed
- Albedo is the term that we use to describe how much of the suns energy is reflected from any surface of the earth
If we were 100% dependent on the Sun to keep us warm half of our planet would freeze every night when it is facing away from the Sun
- These 2 problems require us to have another way to keep Earth’s surface temperature from fluctuating
- The solution is that Earth’s atmosphere acts as a warming blanket helping to regulate our surface temperature
Blanket makes up and function
- The gasses that cause this blanket effect are called “greenhouse gases”
- They are mainly water vapour (H2O) Carbon dioxide (CO2) Methane (CH4) and Nitrogen Dioxides (N2O)
- These gasses have the ability to trap radiated energy from the Earth’s surface and then release it back
- This prevents the Earth’s energy from being lost in space
How do these gasses do this?
- All of the gasses are made up of 2 or more elements tightly bonded together
- When they absorb energy from the Earth’s surface it causes each of the elements in the gas to vibrate
- Once the element settles back down the energy is released to be absorbed by another gas molecule or surface
- Scientists have been using the term “greenhouse effect” to describe the regulation of earth’s temperature since the 1800s
- In the 1950s the term was used to describe the effects of climate change
- Now we use the term anthropogenic greenhouse to describe the effects of climate change
- It is important to remember that without the Earth’s natural greenhouse effect, life would not be possible