2. Is the Earth able to receive the whole radiation generated by the Sun ? Why?
A
Answers
No, because the earth is protected by the ozone layers which hold all the radiation from the sun but as of now, our ozone layers has a hole which means that the radiation of the sun is directly entering the earth's atmosphere.
Answer:
The air surrounding us consists of different gases and also some particles. This layer of air, known as the Earth’s atmosphere is retained by gravity. The two main components are nitrogen (78%) and oxygen (21%). Besides containing the oxygen human beings and other organisms need to live, the atmosphere has a number of other “features” such as absorption of ultraviolet radiation from the Sun by the ozone layer and heat retention known as the greenhouse effect.
Solar radiation that is not absorbed or reflected by the atmosphere (for example by clouds) reaches the surface of the Earth. The Earth absorbs most of the energy reaching its surface, a small fraction is reflected. In total approximately 70% of incoming radiation is absorbed by the atmosphere and the Earth’s surface while around 30% is reflected back to space and does not heat the surface. The Earth radiates energy at wavelengths much longer than the Sun because it is colder. Part of this longwave radiation is absorbed by greenhouse gases which then radiate energy into all directions, including downwards and thereby trapping heat in the atmosphere.
Without this natural greenhouse effect, the Earth’s average surface temperature would be an inhospitable -18°C (0°F) instead of the 14°C (59°F) we experience today. This effect is enhanced by increasing greenhouse gas concentrations in the atmosphere due to emissions by human activities such as burning fossil fuels. The main long-lived greenhouse gases are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). But they are not the only forces at work.
Water vapour
Water vapour is the most abundant greenhouse gas. It does not stay in the atmosphere for very long but plays a key role in our climate and its variability and change.
Ozone
Ozone in the lower part of the atmosphere acts as a greenhouse gas and is a major pollutant. Higher up, in the stratosphere, the ozone layer absorbs solar ultra-violet radiation and affects how much of the Sun's heat is radiated back into space. The ozone layer shields us from the harmful effects of excessive UV radiation, which can lead to sunburn, skin cancer and eye damage.
Aerosols
The atmosphere also contains small suspended solid and liquid particles. Aerosols are small dust particles that float in the atmosphere. They result mostly from chemical reactions between gaseous air pollutants, rising sand or sea spray, forest fires, agricultural and industrial activities and vehicle exhausts.
Aerosols affect many aspects of human health and the environment, visible in the case of strong smog or haze events. Aerosols influence Earth’s climate both directly, by scattering and absorbing sunlight, and indirectly, by altering the reflectivity of clouds. In general, aerosols have a cooling effect on climate, which partially counterbalances the heating effect of greenhouse gases. Under certain circumstances, however, they may cause additional heating, such as the case of black carbon in soot.
The gases and dust particles thrown into the atmosphere during volcanic eruptions have influences on climate and cool the planet by shading incoming solar radiation. The cooling effect can sometimes last for months to years.
Albedo effect
Albedo is the ability of a surface to reflect sunlight (solar radiation). Snow and ice have high albedo – much of the sunlight hitting surfaces covered with snow and ice bounces back. In contrast, dark earthy surfaces have a low albedo, therefore, they absorb more sunlight. Thus, the proportion of Earth’s surface that is covered by ice and snow affects how much of the Sun’s solar radiation is absorbed, warming the planet, or reflected. Therefore, snow and ice which are covered in soot from pollution no longer reflect sunlight, but absorb it and so melting increases.
The more snow and ice in the Arctic and Antarctic melt, the more dark surfaces. Hence, the feedback of climate change in the Polar regions is further warming, exacerbating climate change globally.
Explanation: