Carbon dioxide (CO2)

Definition

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in Earth's atmosphere in trace amounts. It plays a crucial role in the carbon cycle, serving as a key component for photosynthesis and respiration, while also acting as a greenhouse gas that contributes to climate change and global warming.

5 Must Know Facts For Your Next Test

1. Carbon dioxide is produced naturally through processes like volcanic eruptions, respiration of animals, and decomposition of organic matter.
2. Human activities, such as burning fossil fuels and deforestation, have significantly increased atmospheric CO2 levels since the Industrial Revolution.
3. CO2 is essential for photosynthesis; plants absorb it from the atmosphere to produce oxygen and glucose.
4. The concentration of CO2 in the atmosphere is measured in parts per million (ppm), and current levels are over 400 ppm, significantly higher than pre-industrial levels.
5. As a greenhouse gas, CO2 absorbs infrared radiation, contributing to the greenhouse effect and leading to global temperature increases.

Review Questions

• How does carbon dioxide play a role in both photosynthesis and respiration?
  • In photosynthesis, carbon dioxide is absorbed by plants and converted into glucose and oxygen using sunlight. This process is vital for plant growth and supports life on Earth. Conversely, during respiration, animals inhale oxygen and exhale carbon dioxide as a byproduct of metabolizing glucose for energy. This exchange of gases illustrates the interconnectedness of life processes within ecosystems.
• Evaluate the impact of human activities on atmospheric carbon dioxide levels since the Industrial Revolution.
  • Human activities have dramatically increased atmospheric carbon dioxide levels due to industrialization, primarily through the burning of fossil fuels like coal, oil, and natural gas. Deforestation further contributes to this increase by reducing the number of trees available to absorb CO2. This rise in CO2 levels has been linked to climate change, as more greenhouse gases in the atmosphere lead to increased global temperatures and disruptions in weather patterns.
• Synthesize information about the carbon cycle and explain how carbon dioxide influences climate change.
  • The carbon cycle involves continuous movement of carbon among Earth’s atmosphere, oceans, soil, and living organisms. Carbon dioxide plays a crucial role as it is exchanged between these reservoirs through processes such as photosynthesis, respiration, and decomposition. Increased CO2 from human activities enhances the greenhouse effect, trapping more heat in the atmosphere and leading to climate change. Understanding this cycle helps highlight the importance of reducing CO2 emissions to mitigate global warming effects.

Related terms

Photosynthesis:

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of carbon dioxide and water.

Carbon Cycle: The series of processes by which carbon compounds are interconverted in the environment, including the movement of carbon through the atmosphere, hydrosphere, lithosphere, and biosphere.

Greenhouse Gas: Gases in Earth's atmosphere that trap heat, contributing to the greenhouse effect and global warming, with CO2 being one of the most significant.