Context: Greenhouse gases (GHG) such as carbon dioxide (CO2), methane and nitrous oxide play an important role in the atmosphere but when it surpass its normal range caused global warming.
GHGs in atmosphere

• The Earth’s atmosphere is made up of different gases. The temperature of the atmosphere depends on a balance between the incoming energy from the sun and the energy that bounces back into space.
• Greenhouse gases (GHG) such as carbon dioxide (CO2), methane and nitrous oxide play an important role in the atmosphere.
• They absorb some of the sun’s heat and release it back in all directions, including back to the atmosphere.
• Through this process, CO2 and other GHGs keep the atmosphere warmer than it would be without them.
• However, fossil fuel-run industries and other human activities add GHGs to the atmosphere. This, in turn, increases atmospheric temperature, causing global warming.

Assessing the carbon level

• In 1958, American scientist Charles David Keeling calculated the amount of CO2 in our atmosphere.
• When he started his measurements in 1958, the CO2 levels were around 315 parts per million (PPM).
• When he died in 2005, the project was taken over by his son Ralph Keeling. By 2014, CO2 levels had increased to about 400 PPM.
• With his systematic study of atmospheric CO2, Keeling became the first person to alert the world about the increasing levels of CO2 in the atmosphere.

Reasons for rising CO2 levels

• Scientists first argued that the increasing release of methane and CO2 was due to agriculture and livestock.
• But, with the start of the Industrial Revolution in the 18th century, the use of fossil fuels and CO2 levels rose simultaneously.
• Nations that underwent the Industrial Revolution used huge amounts of fossil fuels and became centres of high CO2 emissions, while nations with an agrarian economy emitted less GHGs.
• Over the years, as CO2 levels increased, it sparked off debates and arguments between the GHG-emitting rich industrial nations and the victims of global warming — the poorer nations.