All about the Atmosphere

What is the Atmosphere?

The atmosphere is made up of layers of gases surrounding our planet.

Earth’s atmosphere is a mixture of gases with 78% of Nitrogen, 21% of Oxygen and 1% of other gases. The atmosphere acts as a shield from the sun’s incoming ultraviolet (UV) radiation. This keeps the planet’s temperature regulated and warm enough for life to thrive. The layers in the atmosphere are heated by the sun which in turn causes the convection of air current and weather patterns around our planet.

What are the layers of the Atmosphere?

The atmosphere comprises 5 distinct layers which are:

1. The Troposphere: The layer closest to the earth’s surface. It is about 10 km (6 miles) above Earth’s surface. Most of the earth’s weather, including the clouds we see, rain that pours, winds we feel and the air we breathe occurs in the troposphere. Did you know? : Most aeroplanes fly in the troposphere to avoid turbulence.
2. The Stratosphere: It is the second layer and lies above the troposphere. It extends to about 50 km (30 miles). The ozone layer is in the stratosphere. Ozone absorbs most of the sun’s radiation that would otherwise harm plants, animals and us. It is a very dry layer with very little water vapour so very few clouds form in this layer. Weather balloons go as high as the stratosphere.
3. The Mesosphere: The third layer is the mesosphere. It extends up to about 80 km (50 miles) above Earth’s surface. This is where most meteors burn up upon entry. This layer is the coldest layer -180 degrees Fahrenheit.
4.  The Thermosphere: The fourth layer, the thermosphere or ionosphere reaches about 80-480 km ( 50-300 miles) above the earth’s surface. It is very thin and very cold. Did you know that the Aurora – northern lights/southern lights happen in this layer?
5. The Exosphere: This layer is also called the Magnetosphere. It ends where the earth’s gravity almost becomes zero. Satellites orbit the earth in this last layer of the atmosphere.

How has our Atmosphere changed?

The atmosphere has kept our earth warm and livable for nearly 4 billion years. Did you know without the atmosphere, the Earth’s surface would be frozen all the time?

Water vapour, nitrous oxide, methane, ozone and carbon dioxide are naturally occurring heat-absorbing gases in the atmosphere. They are called greenhouse gases. And the more greenhouse gases in the atmosphere, the warmer the earth gets. Human activities like burning fossil fuel for industries, generating electricity, and transport are releasing a huge amount of carbon into the atmosphere. This carbon combines with oxygen in the air to form carbon dioxide. Another way humans are putting carbon dioxide in the atmosphere is by cutting trees and burning forests. Today there is 50% more carbon dioxide in the atmosphere since the industrial revolution. This has warmed the earth’s temperatures by a little more than 1*c. As global temperatures rise, the climate starts to change. It affects the weather and impacts our world and all living things around us in a big way. Extreme weather and rising sea levels cause habitat loss, disrupt food chains,  and threaten animals, plants and us.