17. Earth's Carrying Capacity

Question 1

Idea of CC

Answer 1

A closed ecosystem has a set amount of resources and can only support so much of life.

Question 2

What’s the Easter Island Metaphor?

Answer 2

Civilization crashed.
Melaneshians colonized ~1000 AD, by the time the Dutch came in 1700s it was barren.
The forest and resources were depleted, exceeding the carrying capacity.

Question 3

What is the concept of spaceship Earth?

Answer 3

In the 1960s the human perception changed due to the spaceship mission.
We realized Earth isn’t a limitless supply of resources.
Can’t exploit Earth.

Question 4

What does the ecological footprint measure?

Answer 4

Measures the demand of human activity on the biosphere.

Question 5

What is biocapacity?

Answer 5

The amount of productive area that’s available to generate resources and absorb waste.
We want to increase this.

Question 6

What is a global hectare?

Answer 6

It expresses ecological footprint and biocapacity with the same currency.
Weigh them by their productivity.

Question 7

What are the assumptions for the ecological footprint?

Answer 7

1. Resources people consume and the wastes they generate can be quantified and tracked.
2. Resource and waste flows can be measured in terms of the biologically productive area necessary to maintain them.
3. The global hectare (gha) can be calculated for different land use types.
4. Because a single global hectare represents a single use of a particular resource, and each global hectare represents the same amount of bioproductivity, ghas can be summed to obtain an aggregate measure of the ecological footprint or biocapacity.
5. Human demand, expressed as the ecological footprint, can be directly compared to biocapacity in global hectares, and can be directly compared to biocapacity at different spatial scales (local, regional, global)
6. Area demanded can exceed area supplied if demand on an ecosystem exceeds that ecosystems regenerative capacity.

Question 8

What is the ecological footprint equation?

Answer 8

EFc=EFp+EFi-EFe

Question 9

What is EFc?

Answer 9

Consumption.

We want to know how much a region consumes.

Question 10

What is EFp?

Answer 10

Production. Resources in an area being produced and harvested.

Question 11

What is EFi?

Answer 11

Imported

Question 12

What is EFe?

Answer 12

Exported

Question 13

What is the ecological footprint of production?

Answer 13

EFp=(P/Yn)YFEQF

Question 14

What is the biocapacity equation?

Answer 14

BC=AYFEQF

Question 15

What is A?

Answer 15

Area available for a given area.

Question 16

What is YF?

Answer 16

A Ratio of national to world average yields

Question 17

What is EQF?

Answer 17

The equivalent factors

Weights the area of specific land use type to gha

Question 18

What are the limitations of the EP concept?

Answer 18

Doesn’t account for:
1. availability/depletion of non-renewable resources
2. Inherently unsustainable activities
– Heavy metals, radioactivity, etc cannot be assimilated
3. Environmental management and harvest practices
– Origin or method of extraction of a resource in a particular place are not accounted for
4. Land and ecosystem degradation
– Doesn’t measure variables that contribute to determining yields – eg. soil structure, nutrient availability, so cannot predict future BC
5. Ecosystem disturbance/resiliency of ecosystems
– Only evaluates the consequences of changes to the ecosystem that affect yield
6. Use/contamination of fresh water
– Difficult to determine biocapacity for hydrological cycles.

Question 19

What is the Global Ecological Footprint in 2007?

Answer 19

18 billion gha

2.7 gha/person

Question 20

What is the global biocapacity in 2007?

Answer 20

11. 9 billion gha

1. 8 gha/person

Question 21

Did we cross Earth’s carrying capacity?

Answer 21

Yes, in 1970-80s

Question 22

Debtors

Answer 22

EP>BC

Like US, China and Europe