Gases in the Atmosphere

Composition of the Atmosphere

The Earth’s atmosphere is made up of various gases, primarily nitrogen (78%), oxygen (21%), argon (almost 1%) and traces of other gases such as carbon dioxide, water vapour and noble gases.
Natural processes such as volcanic activity, natural decay, photosynthesis, and respiration among other processes contribute to the make-up of the atmosphere.

The early atmosphere, often associated with the volcanic activity, was likely rich in nitrogen, water vapour, carbon dioxide, and noble gases.
As the Earth cooled, most of the water vapour condensed and formed the oceans.
Over billions of years, living organisms evolved and participated in a process called photosynthesis, which began to reduce the amount of carbon dioxide in the atmosphere while increasing the amount of oxygen.

Human activities have been linked to changes in the composition of the Earth’s atmosphere, mainly through the increase in carbon dioxide.
Burning fossil fuels such as coal, oil, and natural gas releases stored carbon into the atmosphere as carbon dioxide.
Deforestation, the clearance of forests, reduces the rate at which carbon dioxide is removed from the atmosphere during photosynthesis.
These activities have contributed to a marked increase in atmospheric carbon dioxide over the past 200 years, leading to global warming and climate change.

The increase in atmospheric carbon dioxide contributes to the greenhouse effect, a natural warming of the Earth.
The greenhouse effect occurs because certain gases in the Earth’s atmosphere trap heat from the sun and prevent it from escaping into space. This makes the Earth’s average temperature warmer than it would be.
The augmented greenhouse effect, caused by increased levels of greenhouse gases primarily from human activities, is causing the Earth’s average temperature to rise. This phenomenon is known as global warming.

Besides carbon dioxide, other gases like methane, nitrous oxide, and CFCs (chlorofluorocarbons) also contribute to the greenhouse effect.
Methane is mainly produced from agricultural practices and waste management. Nitrous oxide is released during industrial activities and during the combustion of fossil fuels and solid waste.
CFCs, while not naturally occurring and less common due to their restriction, are potent greenhouse gases if released into the atmosphere.

Global warming and climate change have several potential consequences, including more frequent and severe weather events, sea level rise, and effects on ecosystems and species.
Strategies to mitigate the impact include reducing greenhouse gas emissions, for instance through use of renewable energy sources and improving energy efficiency, planting more trees (afforestation), and using carbon capture and storage technologies where carbon emissions are collected and stored underground.