Water and Carbon cycles: Water, carbon, climate and life on Earth

Question 1

On a local scale, the water and carbon cycles are both ____ systems.

Answer 1

Open

Question 2

On a global scale, the water and carbon cycles are both ____ systems.

Answer 2

Closed

Question 3

What is a dynamic equilibrium in a system?

Answer 3

When energy inputs equals outputs despite changing conditions.

Question 4

What causes positive feedback?

Answer 4

When a chain of events amplifies the impacts of the original event.

Question 5

What causes negative feedback?

Answer 5

When a chain of events nullifies the impact of the original event.

Question 6

What is the cryosphere?

Answer 6

Frozen parts of the planet e.g. ice caps, glaciers, permafrost

Question 7

What is the lithosphere?

Answer 7

The outer section of the earth (crust and upper-mantle)

Question 8

What is the biosphere?

Answer 8

Living and dead organic matter e.g. animals, plants

Question 9

What is the hydrosphere?

Answer 9

All the water on earth e.g. in lakes, water vapour, oceans

Question 10

What is the atmosphere?

Answer 10

Gases that surround the earth.

Question 11

Outline a moorland:

Answer 11

• An expanse of waterlogged, acidic soil and peat- MAJOR stores of CO2.
• Many moorlands have been drained by large channels (no longer submerged) and have been converted into highly productive farmland/plantations in tropical areas due to their fertile soils.
• Caused an icnreased flood risk in local areas as surface storage is reduced by the drianing and streamflow is increased from digging ditches.

Question 12

Outline how the 2 cycles occur in tropical rainforests (natural and deforested):

Answer 12

Natural:
- 75% of precipitation is intercepted by trees, 35% of this reaches the ground and infiltrates soil, 35% is used by plants and is returned to the atmosphere via evapotranspiration.
- 25% evaporates almost immediately.
- Trees suited to warm and humid conditions promotes photosynthesis- trees act as carbon sink.
- Decomposition and respiration releases CO2 back into the atmosphere and soil where it is stored.

Deforested:
- Most precipitation reaches the ground immediately with little vegetation interception, leading to higher SRO and flood risk.
- Less evapotranspiration, so the atmosphere is less humid and rainfall decreases.
- Less photosynthesis, low decomposition rates.
- Fires to clear lands releases CO2 back into atmosphere and soil.

Question 13

Outline how the 2 cycles are interconnected in rainforests:

Answer 13

• Rain over tropical rainforests may occur over deforested land, causing soil erosion.
• Soil and ash will flow into rivers and increase the carbon content of rivers. This water will leave the rainforest cycle as an output via streamflow, leading to desertification, less evapotranspiration and higher temperatures.
• High temperatures could lead to forest migration as some habitats become unsuitable for trees as the climate changes, causing desertification in these areas.
• Alternatively there is reduced rainfall in the intact forest as there is less evapotranspiration in the deforested area. This causes drought periods and the irainforest to deteriorate.

Question 14

Outline methods to mitigate climate change:

Answer 14

Mitigation: Setting targets to reduce greenhouse gas emissions, using renewable energy sources, carbon capturing and sequestration.
Global intervention: COP26 with the Paris Agreement (2 degrees temperature increase since pre-industrial times limit).
Local scale: Improving home insulation, recycling, wise energy usage e.g. public transport, smart meter, calculating personal carbon footprint.