Water, Carbon And Climate Change

Question 1

The role of water and carbon in supporting life

Answer 1

• carbon makes up 18% of the human body
• The carbon content of leaves and woody matter is approximately 50% of their biomass
• through food chains the carbon stored on plants is passed on to animals, where it provides much needed energy for, among other things, breathing, growing and reproducing . Through respiration and decomposition, carbon is returned to the atmosphere in the form of carbon dioxide.
• all living organisms need water to survive- it is needed for drinking and irrigation, it is also a source of power and energy.
• carbon in the atmosphere is essential in photosynthesis to create the atmosphere is essential in photosynthesis to create the carbohydrates needed for plant growth. It is one of the important greenhouse gases that absorb long- wave radiation emitted from the Earth, providing sufficient atmospheric warmth for life to survive.

Question 2

Water cycle Feedback loop

Answer 2

Ice reflects radiation from the Sun so less heat is absorbed by the surface. The extent of the Arctic Ice has been shrinking alarmingly in recent years exposing more water with subsequently less reflection and more absorption of hear from the Sun. This warms the water and further melts and reduces the ice coverage. This affects the type and magnitude of water transfers between land, ocean and atmosphere.

Question 3

Carbon cycle Feedback loop

Answer 3

Warmer temperatures have increased the growing season for plants and this has increased the absorption of carbon frombthe atmosphere

• higher temperatures have, however, started to melt the permafrost particularly in parts of Siberia. Organic matter (plant roots and animaks) trapped in the frozen ground act as an important carbon store. It is estimated that there is more carbon currently stored in the permafrost than exists in the atmosphere . On melting, the organic matter in the permafrost starts to decompose as oxygen is introduced. The bacteria involved in decomposition produce carbon dioxide and methane as a waste product. Thee gases bubble to the surface and escape to the atmosphere

Question 4

Water cycle/ carbon cycle Feedback loop

Answer 4

Phytoplankton are microscopic plant-like organisms that live in water. In common with terrestrial plants that they use the energy of the Sun, together with carbon dioxide (dissolved in the water), to photosynthesise, live and grow. They are the primary producers in aquatic ecosystems sustaining the food w3b. They are also important stores of carbon.

Marine phytoplankton releases a chemical substance DMS that may promote the formation of clouds (condensation) over the oceans. Increases in phytoplankton populations associated with warmer temperatures and more sunshine could therefore lead to an increase in cloudiness and global cooling. This is because clouds reduce the amount of solar radiation reaching the Earth’s surface. Of course, less sunshine might lead to a reduction in the amount of phytoplankton, thereby reducing this cooling effect. This complex feedback loop is an example of negative feedback