In a typical situation, emissions from which category of activities comprise the largest amount of CO2 release into the atmosphere?

Emission of CO2 from burning of fossil fuels (coal, natural gases and oil) is the activity that releases the largest amount of CO2 into the atmosphere.

Explanation:

The emission of CO2 is a major world crisis which is one of the single most contributor to global warming and rapid climate change. Fossil fuels produced from the remains of living organisms millions of years ago, under intense heat and pressure, has been the major fuel source for human industrial and domestic activities. Industries rely heavily on fossil fuels to power their machines and for industrial heating, movement and transportation now heavily depends on fossil fuel energy, and even basic heating and cooking process now depends on fossil fuel. Some of this activities rely on fossil fuel directly, or indirectly; by depending on power generated from power houses that generates electricity from the combustion of fossil fuels in huge generators. The after effect of all these energy demand is that more CO2 than ever is constantly released into the atmosphere.