Uncontrolled migration—spurred by a growing populations, fewer resources like water or arable land as well as increasing conflict—has become a contentious political issue, particularly in advanced economies like Europe and the United States, argue demography experts Joseph Chamie and Barry Mirkin. Passions run high as liberals support assistance and an emphasis on human rights of displaced people while conservatives advocate limits and enforcement. Resources are limited and government responses to unwanted migrants vary including information campaigns, financial assistance to countries with conditions on tougher policies to block migrants, mechanisms for legal migration, refugee support, border security as well as various deportation, relocation, and amnesty programs. Separate or combined, the responses are not enough, Chamie and Mirkin conclude, and ignoring the challenges poses consequences for host nations, governments and migrants.

The United Nations has released population data confirming the continuation of long-term global demographic trends and a larger global population than previously projected.