Earth System Notes

The Earth System

Overview

• Our planet is a dynamic system with interconnected subsystems that influence each other.
• These subsystems include:
  • Atmosphere
  • Geosphere
  • Hydrosphere
  • Biosphere

Scale

• Processes in the Earth system operate on various scales:
  • Length: Microns to thousands of kilometers.
  • Time: Milliseconds to millions of years.

Energy

• The Earth system is powered by:
  • External source: The Sun.
  • Internal sources:
    • Radioactive decay.
    • Gravitational energy (heat from planetary formation).

Cycles

• Physical materials and energy are continually recycled in overlapping cycles.

Earth System Science

Definition

• Earth system science studies the planet as a system of interacting parts.
• It focuses on changes within and among these parts.
• Adopts a holistic approach to understanding the planet.

Components

• The Earth system is composed of interlinking subsystems:
  • Hydrosphere
  • Atmosphere
  • Geosphere
  • Biosphere

Reservoirs

• These spheres house the Earth system’s reservoirs.
• The Earth system is studied by measuring:
  • Mass or volume of material.
  • Exchange of energy passing between Earth’s reservoirs over time.
• The challenge is to determine why and how quickly these changes occur.

Hydrosphere

• Consists of oceans, lakes, rivers, groundwater, and water vapor.

Atmosphere

• Includes the troposphere, stratosphere, and clouds (containing gases, water vapor, and aerosols).

Geosphere

• Comprises continents, seafloor, sediments, lava, and soils (including dust or ash particles).

Biosphere

• Encompasses animals, plants, and bacteria (both terrestrial and marine, and soil).

Flux

• The constant exchange of energy and matter between Earth’s reservoirs is called flux.
• Reservoirs that donate energy or matter are called sources.
• Reservoirs that receive energy or matter are called sinks.

Earth as a System

Closed System

• Earth approximates a closed system where matter and energy are fixed and finite.
  • Energy is freely exchanged.
  • Matter is fixed.
• Free exchange of both energy and matter.

Key Aims of Earth System Science

• Describe the driving processes and measure the fluxes of materials and energy within and between Earth’s reservoirs.
• Explore how the volume, direction, and efficiency of these exchanges change over time.

Thought Experiment

Examples

• Energy: kinetic energy transfer between atmosphere and hydrosphere, and hydrosphere and geosphere
• Matter: carbon atoms transferring between geosphere and atmosphere, and atmosphere and biosphere.
  *What is the impact of the transfer on the sink? How can we measure the efficiency of flux?

Studying Earth System Interactions

Timescales

• Short timescales: time series observations (e.g., South Pole Station, Mauna Loa Observatory).
• Long timescales: written records, oral histories.
• Deep time: geological record.

Preparation

• Reading for Tuesday: pp. 64-76; 104-105; Chapter 7 of the University Bookshop www.wiley.com/college/skinner textbook
• Reading for Wednesday: pp. 101-105
• Watch Men of Rock: Deep Time on YouTube