Most Noticeable Polar ice caps melting
polar ice caps
Polar Ice Caps Melting. Everyday the Suns heats the earth. The energy hits the earth almost 174,000 Terawatts. Since one million megawatts are equal to one terawatt, so the earth is heated by the sun with 174 billion megawatts energy. Because of the white reflectivity of the earth, about 30% of this energy is reflected. It means 122 Terawatts of energy absorbed by our planet.
With this energy, the earth temperature must continue constantly and continue to heat up the earth. Fortunately, it does not happen and the temperature of the earth does not rise constantly or we can say that it has own temperature stability. The reason is at night time the earth radiates into the deep space the heat which is absorbed during the day. From 122 Terawatts of energy which is absorbed from the sun, 1 Terawatts is converted into work for moving the air, the cloud and sea currents. And the difference or about 121 Terawatts, radiates back into deep space.
Radiation always happen by transfers the heat from the hotter to the cooler body. The cooling effect can be felt actually at night, but the truth is the earth is constantly cooling by radiating this energy into deep space all 24 hours. Since the effect of the sun’s radiation is to annul the cooling and go on further to warm the earth, we do not feel it during the day.
Over the millions of years our planet has achieved a balance of its temperature equating the cooling at night and the heating by the Sun.
The sea has a vast reserve of water which is capable to absorb the heat from the Sun without change in its temperature. The radiation from the sun penetrates a long distance down in the water and the heat is absorbed into a very big mass of water. In places where there are plankton or algae as a mixed layer, its depth makes some difference. The sea surface temperature (SST) observation where there was ocean mixed layer (OML) at 5 feet below surface showed a day night temperature difference of 1.5 degrees centigrade. The temperature difference was only just 0.1 degree when the OML was 50 feet deep.
1.3 billion cubic kilometers of water are held by the ocean. Physics has given us a way to calculate the rise of temperature of water knowing its specific heat, mass and the amount of heat input.
The effect of greenhouse gases on global warming for the whole planet is 1.6 watts per sq. meter which works out to a heat input of 800 Terawatts on the surface area of 500 Tera sq. meters as reported by Intergovernmental Panel on Climate Change (IPCC). Without considering the night time radiation from the sea surface, this heat input for the whole year can raise half degree temperature of the sea over a period of 111 years. It is impossible for the increase of greenhouse gases will warm the earth and enough to melt the polar ice caps from underneath.
