Water and Carbon Cycles

Exam Answer
Easy Answer

ESSENTIAL OVERVIEW

“The study of water and carbon cycles focuses on the movement of matter and energy within closed systems at a global scale and open systems at a local scale. It examines the processes, stores, and fluxes that maintain life and regulate Earth’s climate, alongside the human and natural factors that cause these systems to change over time.“

CRUCIAL KEYWORDS

Cryosphere

The portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, and ice sheets.

Carbon Sequestration

The long-term storage of carbon dioxide or other forms of carbon to either mitigate or defer global warming.

Evapotranspiration

The combined process of water surface evaporation, soil moisture evaporation, and plant transpiration into the atmosphere.

Dynamic Equilibrium

A state of balance within a system where inputs and outputs are equal, despite constant movement and change.

Infiltration

The process by which water on the ground surface enters the soil.

Core Processes & Theories

1) The Drainage Basin as an Open System

A drainage basin is an open system because it has inputs of solar energy and precipitation, and outputs in the form of evaporation and river discharge, with stores and flows in between.

2) Negative Feedback Loops

A process that occurs in a system that counteracts a change and helps restore the system to its original state, thereby promoting stability.

3) The Biological Carbon Pump

The process by which marine organisms transfer carbon from the atmosphere to the deep ocean through photosynthesis and subsequent sedimentation.

4) The Slow Carbon Cycle

The movement of carbon between rocks, soil, ocean, and atmosphere over millions of years, primarily through weathering and volcanic activity.

CASE STUDY EVIDENCE

  • The Amazon Rainforest stores approximately 80 to 120 billion tonnes of carbon, making it one of the largest terrestrial carbon sinks.
  • Deforestation in the Amazon reduces evapotranspiration, which leads to a decrease in cloud formation and regional precipitation levels.
  • The Arctic Tundra contains vast amounts of carbon locked in permafrost; however, rising temperatures are causing this to thaw, releasing methane.
  • Intensive farming practices can deplete soil organic carbon by up to 50% compared to natural ecosystems

EXAM ESSENTIALS

  • When discussing cycle changes, always differentiate between ‘natural’ causes like wildfires and ‘human’ causes like fossil fuel combustion.
  • Use quantitative data from your case studies to support your arguments regarding the magnitude of carbon or water stores.
  • Remember that the water and carbon cycles are interdependent; changes in the carbon cycle (warming) lead to changes in the water cycle (increased evaporation).
  • Analyse the impacts of change at various scales, from the local drainage basin level to the global atmospheric level.