Gases

The atmosphere is predominantly made up of nitrogen (about 78%) and oxygen (about 21%), with traces of other gases like argon and carbon dioxide. One key point to note is the variable concentration of these gases at different altitudes. Oxygen, for example, becomes almost negligible at heights above 120 km.

Carbon dioxide is of particular interest meteorologically. While it constitutes a tiny fraction of the atmosphere, its role in climate is disproportionately significant. It allows incoming solar radiation to pass through but absorbs and reflects back the Earth’s outgoing radiation, thus acting like a thermal blanket for the planet. This is the basis of the greenhouse effect, which is critical for maintaining temperatures that can sustain life.

Over recent decades, however, the concentration of carbon dioxide has been increasing, largely due to human activities like burning fossil fuels and deforestation. This is intensifying the greenhouse effect, contributing to global warming.

Ozone is another important atmospheric component, mainly concentrated in the stratosphere between 10 and 50 km above the Earth’s surface. It plays a critical role in absorbing the sun’s harmful ultraviolet rays, thereby protecting life on Earth.

Water Vapour

Water vapour varies significantly in its concentration in the atmosphere, influenced by factors like altitude and geographical location. In warm, tropical regions, water vapor can make up to 4% of the air by volume. In contrast, in arid deserts and polar regions, this can be less than 1%.

Water vapour has a multi-faceted role in atmospheric processes. Like carbon dioxide, it also acts as a greenhouse gas. It traps heat radiated from Earth, preventing it from being lost to space. In this way, it acts like a blanket around the Earth, maintaining a balanced temperature that neither gets too hot nor too cold for life to exist.