However, if in the coming decades America continues with net immigration of about 1.2 million annually, as currently assumed, the US population would reach 420 million by year 2060. Although this projected growth would be an increase of more than 100 million, the US population would fall to fourth place as Nigeria takes over the number three position with a projected population of 460 million in 2060. The populations of the three countries currently larger than Nigeria – Brazil, Indonesia and Pakistan – are expected to peak around midcentury and begin declining thereafter due to projected low fertility rates falling below replacement levels. Also in the longer term, the gap between projected US population, with 1.2 million immigrants annually, versus the larger US population, with 10 million immigrants annually, widens rapidly, resulting in a difference of 1.1 billion Americans at the close of the century…

America could easily accommodate a larger population given its considerable size and abundant resources. A population of 1.6 billion would increase the nation’s density from today’s 33 persons per square kilometers to 165 persons in 2100, about half the level in Massachusetts today. This future density is well below current densities in Germany at 231 per square kilometer; Japan, 335; and the United Kingdom, 255. Even if the world’s entire population of 7.1 billion were to reside in America, the nation’s resulting density of 732 persons per square kilometer would still be less than current densities of Bahrain, at 1,818; Bangladesh, 1,033; and Singapore, 7,447.

Increased demands for food, housing and energy could be handled with a revitalized US economy and developing underutilized land and natural resources, including natural gas and renewable sources of energy. Innovation and technology could alleviate negative environmental impacts, as has been demonstrated over the nation’s two-century history.