HUMAN POPULATION GROWTH

Population in Billion

You guessed it exponential growth! Is this exponential growth (J-curve) or logistic growth (S-curve)? You guessed it exponential growth!

3 million years to get to 1 billion 1830 100 years to 2 billion 1930 30 years to 3 billion 1960 15 years to 4 billion 1975 12 years to 5 billion 1987 12 years to 6 billion 1999 12 years to 7 billion 2011 Projected 8 billion 2025

At the present rate, we are adding to the world: A New York city every month A Germany every year An India every 10 years

The good news is that we are not growing as fast as we were.

However, we are not growing at the same rate everywhere in the world, take a moment to look at the data in the next slide.

https://www.cia.gov/library/publications/the-world-factbook/rankorder/2002rank.html

Zero Population growth (ZPG) Birth rate = death rate This means that the population stops growing because births and deaths occur at the same rate.

Population momentum Term that is used to describe the fact that if one has no immigration, and if one makes a sudden change in the fertility rate, the full effect of the change will not be realized until all persons have died who were living at the time the change was made.

Age Structure diagrams The age structure of a population is usually shown graphically The population is usually divided up into pre-reproductive, reproductive and post-reproductive ages The age structure of a population dictates whether it will grow, shrink, or stay the same size