Question

exponential growth/decay

Answer 1

That is the equivalent of 2.5 California's per year, or 1 new Germany per year. It is 1.6 million people per week (one New Mexico per week), or 221,000 people per day (one Charlotte, NC added per day!).

An astounding growth rate, even though the net reproductive rate is actually quite small. But growth is not evenly distributed around the world. Certain countries are growing faster than others, while some are actually losing growth (deaths and emigration exceed births plus immigration - Albania is an example).

Why the Increase in Human Population Growth Rates This Century?

Remember, only two things affect population growth: births and deaths. So, have these changed?

Birth rates: have been constant for many years at about 22 babies/1000 people/year

Death rates: have declined dramatically due to more food, less disease, more social structure

Death Rates in 1900: 20/1000/year Net Reproductive Rate 1900: 22-20/1000 = 0.002 or 0.2%

Death Rates in 2000: 9/1000/year Net Reproductive Rate 2000: 22-9/1000 = 0.013 or 0.13%

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