Environmental damage is proportional to the population density. Overpopulation leads to fresh water and food shortage. Compared to the population growth, the increase in carbon emissions was faster in developing countries than in high-income ones. The populationrelated factors are expected to be critical in the dynamics of climate changes. Related topics of temporary and fictive marriages, sexual and reproductive coercion are discussed here. Besides, the current conflict in Ukraine is briefly delineated. The need for the birth control in overpopulated parts of the world has been obfuscated by conflicting national and global interests: the population growth has been regarded as a tool helping to the sovereignty and defense. High fertility has been propagandized to boost up military and labor resources. Smoldering international conflicts contribute to higher birthrates. An authority concentrated in the most developed parts of the world could counteract the global overpopulation, ethnic and gender shifts thus preventing international conflicts.