Why is Carbon important?
- Carbon dioxide is an important ingredient for photosynthesis, which helps plants prepare their own
- The carbohydrates, fats, proteins also contain carbon in some form or the
- Endoskeletons and exoskeletons of organisms like marine animal shells are also made up of carbonate
What is the Carbon cycle?
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the various spheres of earth.
The carbon cycle can be understood easily as two interconnected subcycles:
- Biological carbon cycle
- Geological carbon cycle
Let us begin with the first one.
- Biological carbon cycle: Autotrophs capture carbon dioxide from the air or bicarbonate ions from the water and use them to make organic compounds such as sugar. Heterotrophs like herbivores and humans consume these autotrophs and this organic carbon that is sugar is passed through food chains and webs. To release the energy stored in carbon-containing molecules, such as sugars, autotrophs and heterotrophs break these molecules in a process called cellular
respiration. In this process, the carbons of the molecules are released as carbon dioxide. Decomposers also release carbon dioxide when they break down dead organisms.
- Geological carbon cycle: On land, carbon is stored in the soil as organic carbon from the decomposition of living organisms or as inorganic carbon from weathering of terrestrial rock and minerals. Deep under the ground, we find fossil fuels which are the remains of plants and animals that are decomposed under anaerobic conditions. These fuels are very very precious and non- renewable as it takes millions of years to When humans burn these fuels, carbon is released back into the atmosphere in the form of carbon dioxide. Thus completing the cycle.
There is yet another way, where carbon can enter back into the atmosphere that is during volcanic eruptions.
The geological pathway of the carbon cycle takes much longer than the biological pathway. It can in fact take around millions of years for the geological pathway of the carbon cycle to complete its one round.
Carbon cycle
  What is the Greenhouse effect?
The greenhouse effect is a process that occurs when gases in Earth’s atmosphere traps the Sun’s heat reflected from earth.
Greenhouse effect
Greenhouse
 Let us try understanding this effect better.
A few gases let in light but keep heat from escaping, like the glass walls of a greenhouse. These gases that are responsible for trapping heat are called greenhouse gases. Examples of the same are carbon dioxide, water vapour, nitrous oxide, methane.
In the atmosphere, greenhouse gas molecules trap some of the heat, and the rest escapes into space. Without this process, life would not have been possible on the earth as it keeps the earth warm. But now the same life-saving process is proving to be life-threatening. Because the concentration of greenhouse gases is increasing due to increased air pollution and also due to the extensive cutting of trees. Hence more heat is getting trapped in the atmosphere.
As a result, the average temperature of the earth’s atmosphere is gradually increasing. This is called global warming. Global warming is the major reason for the erratic rainfalls, hotter summers, floods, glacier melting and many more