As resources in a population become less available population growth will decline. An ecosystem can support the growth of a population up to a certain number which is called the carrying capacity of the ecosystem.
Once the carrying capacity is reached in an ecosystem the growth of the population will stop and there will not be any increase in the number of individuals due to limitation of the resource for growth.
So if the resource in the population becomes less available then it can not support the high growth of a population because it decreases its carrying capacity and ultimately decrease the population growth.
Since variations in air pressure drive the winds on Earth, isobars also give meteorologists an easy way to assess wind direction and speed. Closely spaced isobars indicate large pressure changes over a small area, causing wind speeds to increase.