Chapter 18, Problem 1TYC

To determine

The consequences that occur when solar radiation reaches the Earth and also the way in which the greenhouse gases warm the lower atmosphere.

Answer to Problem 1TYC

About 70% of incoming solar radiation will be absorbed by the atmosphere or surface of the Earth and the remaining 30% reflected back into the space. Greenhouse gases in the lower atmosphere absorbs the outgoing solar radiation from the surface and then reradiated and thereby warms the air.

Explanation of Solution

There are three natural factors that regulate the climate of Earth, namely sun, atmosphere and ocean. The Sun is the ultimate source of energy that warms Earth and prevents it from freezing. The atmosphere helps in maintaining relatively constant day and night temperature and the ocean store and transport moisture and heat. These three factors maintain a fairly constant temperature on Earth.

About 70 percent of total incoming solar radiation is absorbed by the Earth while remaining 30 percent is reflected back into the space. The incoming solar radiation controls a range of processes from photosynthesis to wind movements to evaporation.

The surface of earth absorbs radiation from sun during day and emits infrared radiation having longer wavelength than that of visible light during night. The infrared radiation is absorbed by greenhouse gases such as water vapor, methane, carbon dioxide and nitrous oxide present in troposphere. This absorption warms the Earth and thereby helps to maintain a constant temperature on Earth.

The burning of fossil fuels produces greenhouse gases such as carbon dioxide and nitrous oxide. The increase in levels of these gases in the atmosphere leads to more absorption of infrared radiation. As a result warming of lower atmosphere occurs and this phenomenon is known as greenhouse effect.