Factors affecting the Earth’s temperature
The Sun is the Earth’s primary source of energy.
As shown in Fig 2.1, solar radiation reaches the Earth in the form of shortwave radiation. After going through a number of physical processes including reflection, absorption, evaporation, conduction, convection and radiation, some of the energy is directly reflected back to space, some is distributed to different Earth systems, e.g. atmosphere, ocean, land and ice sheet, and some is radiated back to space in the form of longwave radiation.
If the energy reaching the Earth is more than the energy leaving the Earth, positive energy imbalance will result and the Earth will warm.
If the energy reaching the Earth is less than the energy leaving the Earth, negative energy imbalance will result and the Earth will cool.
Fig 2.1 Earth’s energy budget i
There are three factors affecting the Earth’s temperature, namely, the solar radiation reaching the Earth, Earth’s albedo and atmospheric concentration of greenhouse gases.
Fig 2.2 Factors affecting the Earth’s temperature