GeoMag

L AY E R S O F T H E E A R T H

AMRIT SHARMA

LAYERS OF THE EARTH

Layers of the Earth The weather and climate have a profound influence on the Earth and its inhabitants; the climate is part of our daily experience and is the premise for our health, food and well-being. The effects that humans have on the climate is arising to be a matter of concern, yet there are layers to what we can control and the effect this has on our world. This leads to the climate system, which consists of 4 major components: (1) atmosphere, (2) hydrosphere, (3) cryosphere, (4) land surface/ biosphere. All these elements are directly affected by the Sun, which is the largest external force that will be affecting these components. Atmosphere The atmosphere is defined as the layers of gases surrounding a planet, as the air and gases that engulf objects in space like planets and stars. It is the most unstable part of the climate system as it is always changing and changing alongside the Earth’s evolution. The Earth’s atmosphere is composed of about 78% nitrogen, 21% oxygen, and 0.93% argon. All these gases have very little interaction with the sunlight emitted but very few gases in the 1% absorb and emit infrared radiation. The result of these 15 interactions is greenhouse gases. 0.65% of the water vapour is known to be a natural greenhouse gas. Slightly lower down the earth (35km) is the ozone layer which plays an essential part in protecting the Earth from harmful ultraviolet radiation from the Sun. The greenhouse gases formed put holes in our ozone layer and damage it to the extent where damaging radiation is reaching the Earth. Hydrosphere The hydrosphere is the part of the Earth’s surface that is covered by water; every body of water makes up this layer. This includes oceans, seas, rivers and lakes. Furthermore, the water on Earth is ironically not only on Earth but also within the atmosphere e.g. clouds, and also under the surface of the Earth e.g. water in frozen forms underground. In the case of the hydrosphere, the water molecules are absorbed by Sun. This leads to higher temperatures as the water is evaporated and thus the water cycle.

Cryosphere The cryosphere, including the ice sheets of Greenland and Antarctica, is all the frozen regions of the Earth. Examples of the cryosphere includes snow, sea ice, lake and river ice, icebergs, glaciers, and ice caps, ice sheets and ice shelves, permafrost and seasonally frozen ground, and solid precipitation. The cryosphere of the Earth is made up of these distinct types of frozen water and it contains three-quarters of the world’s freshwater. The cryosphere is highly reflective of all solar energy; the excessive amounts of water stored in all these ice sheets may cause sea levels to vary in their volume. Biosphere In terms of land surface, anything from vegetation to soil controls how energy received from the Sun is returned into the atmosphere. Therefore, the biosphere influences the amounts of some of the major greenhouse gases such as methane, carbon dioxide, and nitrous oxide that come into contact with the rest of the atmosphere. The land surface may also be considered as a part of the biosphere as this is the portion where life is found and sustained. So, the sky where birds fly may be considered as the biosphere; in contrast higher up the atmosphere life cannot be sustained and is not part of the biosphere.

Crocodile Munro Todd

08 | Geographical Magazine • Merchant Taylors’ School

2021/22 Edition | 09