Final answer:
Population changes in the 21st century have caused several issues for Americans, including debates over cultural identity and citizenship, the influence of religion on society and policy, and the sustainability of resource consumption as the global population increases.
Step-by-step explanation:
As Americans entered the 21st century, various issues emerged due to changes in the population dynamics. Population growth coupled with advances in medical technology have led to increased longevity, shifting populations from rural to urban settings, and changes in family size as a result of factors like birth control and higher child-rearing costs. This transition raises important questions about sustainability, resource consumption, economic impact, and social dynamics.
New ethical and cultural disputes surfaced around definitions of citizenship, cultural identity, and the role of religion in society, affecting public policy on topics like climate change, gay and lesbian rights, and reproductive rights. At the same time, globalization facilitated an integrated world economy, posing challenges related to environmental impacts, such as deforestation and desertification from over-farming.
The integration of demography, fertility, mortality, and migration is crucial for understanding the distribution and impacts of the global population. The current patterns of consumption appear to be unsustainable given the projections of population growth and the resultant strain on Earth's resources. Amidst the concerns about overpopulation, there are also fears of depopulation, which could lead to aging populations and economic stagnation due to a lack of a robust labor force.