Carbon Cycle and Climate Change Explained

Carbon Cycle

CO2 is produced by combustion of biomass and fossilized organic matter.

Animals such as reef-building corals and molluscs have hard parts composed of CaCO3 and can become fossilized in limestone.

Carbon Return to Atmosphere

Processes by which carbon returns to the atmosphere include:

• Combustion
• Oxidation
• Respiration
• Volcanic eruption
• Decomposition
• Release from the Ocean

Carbon Reservoirs and Sinks

Major reservoirs and sinks for carbon include: coal, soil, gas/oil, limestone, and the atmosphere.

Carbon dioxide is converted by autotrophs into carbohydrates via photosynthesis and returned to the atmosphere as CO2 through respiration (these are carbon fluxes).

Carbon in Aquatic Ecosystems

In aquatic ecosystems, carbon exists as dissolved CO2 and bicarbonate ions.

CO2 diffuses from the atmosphere into water or is taken up directly by aquatic autotrophs.

CO2 is also produced by respiration in both terrestrial and aquatic organisms.

Methane Production and Fate

Methane (CH4) is produced from organic matter in anaerobic conditions by methanogenic archaea. It can diffuse to the atmosphere or accumulate in the ground.

In the atmosphere, methane is oxidized to CO2 and H2O.

Methane (CH4) is a colorless, flammable gas and the major constituent of natural gas. It is used as a fuel and is an important source of hydrogen and various organic compounds.

Climate Change

Greenhouse Gases and Their Impact

CO2 and water vapor are among the most significant greenhouse gases.

Other important greenhouse gases include methane (CH4) and nitrous oxide (N2O).

The impact of a greenhouse gas depends on its ability to absorb longwave radiation and its concentration in the atmosphere.

Greenhouse gases absorb longwave radiation, trapping heat in the atmosphere.

Concentrations of greenhouse gases directly influence global temperatures and climate patterns.

There is a strong correlation between the rising atmospheric concentration of CO2 since the Industrial Revolution and the increase in global average temperatures.

The recent increase in CO2 concentration is primarily due to the increased combustion of fossilized organic matter.

What are Greenhouse Gases?

Greenhouse gases are atmospheric gases that absorb infrared radiation and re-emit heat in all directions.

This process increases the Earth's temperature, leading to global warming.