Limits of the Planet

Question 1

Uneven environmental change

Answer 1

Quality of the environment is changing unevenly across the globe

Question 2

What are the 4 key drivers of environmental change?

Answer 2

Food
Energy
Water
Resources

Question 3

Gaia Hypothesis

Answer 3

Living organisms and inorganic surroundings interact to form a self-regulating complex system that maintains conditions for life on Earth.

Question 4

Daisy world

Answer 4

A hypothetical planet where white daisies cool the planet and black daisies heat it. This interaction is a metaphor for global regulatory processes.

Question 5

Components of the Earth system

Answer 5

Atmosphere
Geosphere (lithosphere)
Biosphere
Hydrosphere
Cryosphere

Question 6

Define the atmosphere and its functions

Answer 6

The gaseous layer surrounding the Earth

Functions:
- Receives solar radiation which warms the Earth.
- Facilitates the distribution of water across the planet.
- Contains essential gases which are necessary for life processes.

Question 7

Define the geosphere and its functions

Answer 7

The solid part of the Earth, composed of rocks and minerals.

Functions:
- Provides nutrients to the biosphere through soil formation.
- Influence the Earth’s magnetic field and geological activity.

Question 8

Define the hydrosphere and its function

Answer 8

All the water on Earth

Functions:
- Regulates the Earth’s temperature
- Supports aquatic life

Question 9

Define the cryosphere and its functions

Answer 9

The frozen water part of the Earth system

Functions:
- Reflects sunlight, regulating the Earth’s temperature.
- Stores large amounts of freshwater

Question 10

Define the biosphere and its functions

Answer 10

The global sum of all ecosystems

Function:
- Promotes essential processes for life
- Cycling of matter

Question 11

Planetary boundaries concept

Answer 11

9 critical Earth system processes that maintain the stability of the planet

Question 12

What are the planetary boundaries?

Answer 12

Climate change
Biosphere integrity
Ozone depletion
Ocean acidification
Biogeochemical flows
Land system change
Freshwater use
Atmospheric aerosol loading
Novel entities

Question 13

Planetary boundary: Climate Change

Answer 13

Threshold: 350 ppm C02
Current level: Surpassed

Question 14

Planetary boundary: Biosphere integrity

Answer 14

Genetic Diversity:
- Threshold: 10 extinctions per million species per year.
- Current: 100-1000 extinctions per million species per year

Functional Diversity:
- Threshold: Biodiversity intactness at 90%.
- Current: 84%

Question 15

Planetary boundary: Ozone depletion

Answer 15

Threshold: <95% PI O3
Current: >95% PI O3

Question 16

Planetary boundary: Ocean acidification

Answer 16

Threshold: >80% PI aragonite saturation
Current Level: 84% PI aragonite saturation

Question 17

Planetary boundaries: Biogeochemical flows

Answer 17

Phosphorus (Global):
- Threshold: 11 Tg/year
- Current: 22 Tg/year

Phosphorus (Local):
- Threshold: 6.2 Tg/year
- Current: ~14 Tg/year

Nitrogen (Global):
- Threshold: 62 Tg/year
- Current: ~150 Tg/year

Question 18

Planetary boundaries: Land-System change

Answer 18

Global
- Threshold: 75% original forest cover
- Current: 62%

Biome:
- Threshold: 50-85% potential forest cover
- Current: ?

Question 19

Planetary boundaries: Freshwater use

Answer 19

Threshold: 4000 km³/year
Current: 2600 km³/year

Question 20

Planetary boundaries: Atmospheric aerosols

Answer 20

Threshold: AOD < 0.25
Current: 0.30.

Question 21

Planetary boundaries: Novel entities

Answer 21

Threshold: ?
Current: ?

Question 22

Anthropocene

Answer 22

A proposed geological epoch marked by significant human impact on Earth’s systems

Question 23

Tipping points

Answer 23

Critical thresholds where small changes lead to drastic shifts in the state or behavior of a system. Once crossed, the changes can be irreversible.

Question 24

Malthusian Dilemma

Answer 24

Human population growth will eventually outpace food production, leading to widespread famine, conflict, and collapse.

Question 25

Criticisms of Malthusian Dilemma

Answer 25

Technological innovations have temporarily alleviated the pressures

IPAT equation suggests that affluence and technology are more significant in determining environmental impacts

The distribution of resources and consumption patterns are the problem

Question 26

Neo Malthusian

Answer 26

Extends Malthusian concerns to include broader environmental and social consequences.

Question 27

Carrying capacity

Answer 27

The theoretical limit of population that an environment can sustain indefinitely without degrading the resources on which it depends.

Question 28

Political Ecology

Answer 28

Environmental decline is not a natural outcome of population growth, but rather the result of human political and economic decisions.

Question 29

Marxist Political Ecology

Answer 29

A view that links environmental degradation directly related to the capitalist system, coining the term “Capitalocene” to describe the current epoch dominated by capitalism and its impact on the environment.