Interactions

 The people in two groups can avoid interacting with each other, remaining in isolation. They each have an amount of habitat (resources that meet the needs of people and other species), and waste (resources that displace habitat).

People in each group can interact with each other, with several results based on the rates of change of people, habitat, and waste. 

COMPETITION: 

Domination – One group dominates the other by killing its members.

War – The groups fight each other, replacing people with waste. 

COOPERATION:

Sum – The groups live together, meeting their basic needs and not changing the amount of people or waste.

Restoration – The groups live together, increasing habitat by having less people and less waste. 

Cleanup – The groups live together, increasing habitat and reducing waste. 

EXPLOITATION:

Consumption – The groups reduce habitat by converting it into people and waste.

Collapse – Habitat is reduced to less than what is needed for people to survive, resulting in mass die-off.

If one group is the global population and the other is the next year’s global population, then mostly consumption has occurred, with very few years of cleanup. Collapse is likely soon.

ABOVE: Example of two groups and results of interaction. Area is proportional to the amount of resources. The amount of people is equal to the needs they consume.