How could there possibly be 2 million killed in the wars on just one side. Total losses would approach 4 million together. There couldn’t be that many people here since the flood could there?
I have written a little about Book of Mormon population numbers before, but I don’t believe I’ve ever done it for the Jaredites. Calculating potential population purely from elapsed time take the form of the following equation:
[base population] * ([population growth rate] ^ [number of years elapsed])
The Jaredites arrived in the New World after the fall of the tower of Babel, which occurred about 2000 BC. Coriantumr, the last warring Jaredite, lived to see the people of Zarahemla. This would have been no earlier than 600 BC, since Lehi’s party was just starting their journey at that time. This means the Jaredites had more than 1400 years of growth, but we’ll use this value as a safe lower limit.
When the Jaredites arrived, the sojourning party consisted of Jared, his brother, and “about” 22 other men (Ether 6:16). If we assumed each of these other men represented a family of four we have 88 people, plus Jared’s family of at least 14 (Jared, wife, and 12 children) and his brother’s family of at least 24 (brother, his wife, and 22 children) (Ether 6:20). That’s 126 people for our starting population. For the sake of round numbers, let’s be stingy and call it 100 people.
For population growth rate we’ll have to guess. This value is based on the increase in a population year over year from birth and immigration. We’ll have to estimate this since we don’t have access to Jaredite census records. The current global population growth is 1.1%, but since we’ve been playing it safe we’ll use China’s value which, although notorious for trying to reduce it’s growth, still averaged 0.85% the last 20 years. When we plug it into the equation it will be 1.0085 since each year the new population is 100.85% of the previous year.
That now bring our equation of low values to:
100 * (1.0085 ^ 1400)
So at the time of the final Jaredite battle, the population could have been as numerous as 14,004,369 people! In fact, with this base population and growth rate, it would take 1250 years to reach 4 million, meaning they could have reached that size and plateaued for 150 years. A greater base population and larger population growth rate will, of course, get us to 4 million sooner with a much larger population at the last battle.
Since we’ve done the math and you’re still with me I’ll ask and answer a follow-up question. If the math says there should have been more than 14 million people, why are we only hearing about Coriantumr’s 2 million (Ether 15:2)? Shouldn’t it be more like 7 million or more?
There’s another factor of population size that comes into play called carrying capacity. This means that if the environment only supports 2 million people, then you will not have more than 2 million people. Increasing birthrates or immigration will only result in more starvation or predator-related deaths. Carrying capacity is not a hard upper limit, since historically we’ve been able to affect carrying capacity through ingenuity. For instance, a region with a naturally low carrying capacity due to lack of water to support crops can have the carrying capacity increased by introducing irrigation. Typical population growth charts will show explosive growth from the compounding growth rate, followed by a tapering off as it approaches the carrying capacity, followed yet again with explosive growth as capacity barriers are overcome.
Based on the account in the book of Ether, the limiting factor of the Jaredite population looks to be the carrying capacity of the region they settled rather than the amount of time they had to fill it.