When is it possible for a population growth rate to be less than zero?
1 Answer
The population growth is less than 0 whenever the death rate is greater than the birth rate, and the population is getting smaller as time goes on.
Explanation:
The growth rate of the population is the difference between the birth rate and the death rate. Say the birth rate of a certain population is 5,000 a year, and the death rate is 3,000 a year. The difference is 2,000 and hence the growth rate is 2000 per year. If the death rate were to become 8,000 deaths a year, then the difference would be -3,000 and so the growth rate would be negative.
Common causes of negative growth rates would be disease, overpopulation, or lack of food and other necessary resources. Plagues can decimate a population and drastically increase the death rate, but they usually pass as time goes on. Droughts, floods, and other natural disasters can directly kill members of a population, but can also destroy their food supply, further increasing the death rate, potentially resulting in a negative population growth rate.
In the case of humans, the population of a certain country could decrease if emigration is greater than the number of births and the number of immigrants.
