One way to know if we have reached the carrying capacity of the land is to check the health of the population. Underfed, weak, diseased populations are a sign of too many numbers chasing too few resources like air, water, space and food.
The first major human impact on the environment came when hunter-gatherers learned agriculture and cleared forests for field. But the impact was within the carrying capacity of the land. With the industrial Revolution, machines began to replace humans and animals. Machines worked faster and produced more. But using machines led to more pollution than ever before.
Factory towns grew where fields’ and forests had once been. People flocked to work in cities and it caused the growth of shanty towns and slums. Factories always looking for profits, often released toxic s without treating it which meant adding to pollution.
Effects of pollution on the ecosystem –fields
Fields are pumped with pesticides and chemical fertilizers so that more crops can be produced in less time. High rise and big dams and large canals store river water and often floods fields. Soon, the soil gets too slushy to support any crop.
Easter Island or Rapa Nui is in the Pacific Ocean.
Once upon a time, around AD 500, the islands were lush green with trees. Today, they are virtually barren.
Was it a climate change during the little ice age (for 200 years from 1650) or was it a population crisis?
No one knows for sure. But some scholars firmly believe that the island was first occupied by about 400 Polynesian adventurers near AD 500. They cut down trees for boats, stilts for homes and to pull Moai or stone statues. They had enough fish to eat, so their numbers grew to thousands. The Europeans landed in the eighteenth century. The island was full of bananas, sweet potato and sugar cane.
One visitor wrote that just three days’ planting could feed the island for a year. In the absence of trees to take the impact of pelting rain, top soil was washed away. No wood for new boats, no fish for food and people began eating chickens and rats.
Once chickens and rats were over, they may have eaten other people. Sheep, introduced by Europeans, are up more of the greens. In 20002, there were just 3791 people left on the island of who only about 2274 were original Rapa Nuians.
The island had enough produces of food to begin with. Then, with the number of consumers growing, it ran out of food. The overpopulated land could not carry any more people.