Question

Scientific evidence indicates that the CO₂ added to the air by the burning of wood and fossil fuels is contributing to global warming, a rise in global temperature. Tropical rain forests are estimated to be responsible for approximately 20% of global photosynthesis, yet the consumption of large amounts of CO₂ by living trees is thought to make little or no net contribution to reduction of global warming. Explain why this might be the case. (Hint: What processes in both living and dead trees produce CO₂?).

Short answer

When the tropical rain forest contributes a high percentage of oxygen to the atmosphere, simultaneously they are also contributing the carbon dioxide in the atmosphere during the night. Coal is an example of fossil fuel; when it is burnt, it leads to more carbon dioxide production in the environment.

Step-by-step solution

Global warming

Global warming refers to the enhancement of global temperature due to various factors such as by emission of pollutants by vehicles and the burning of wood. The burning of fossils releases a large quantity of carbon dioxide.

Meaning of photosynthesis

The photosynthesis process occurs when there is sunlight, that is, in the daytime. The tropical rainforest has contributed a high amount of photosynthesis; in this process, carbon dioxide is taken in, and oxygen is given out.

At the nighttime, where there is no light, photosynthesis does not occur, and thereby carbon dioxide is released out in theatmosphere again that gets compensated with the daytime. The photosynthesis process requires sunlight, in which carbon dioxide molecule is utilized, and oxygen molecule is released during the formation of sugars in the plants.

Photosynthesis helps in increasing some amount of oxygen to the environment.

Effects of cellular respiration in plants

Carbon dioxide level rises in the atmosphere due to cellular respiration. In the Kreb cycle, decarboxylation occurs and also in the formation of acetyl Co-enzyme A.

Thereby cellular respiration levels ups carbon dioxide in the air that gets compensated by photosynthesis (consume carbon dioxide).