Biologists expect that at least half of the roughly 10 million species alive today will go extinct during the next few centuries due to habitat losses alone. Among global trends affecting biodiversity, the most hopeful is the recent slowing of human population growth. This is to a large extent the product of changing ideals of family size and improved access to family planning. An early peak in human numbers, a possibility within the next 40 years, would dramatically improve the prospects for saving wild species and the ecosystems in which they live and evolve.
Population growth is among a handful of underlying causes leading to biodiversity loss .
Recent studies conclude that the underlying causes of biodiversity loss include population growth, migration to ecologically sensitive areas, poverty and inequity, policies that promote unsustainable resource consumption, and a lack of environmental awareness. In order to slow biodiversity loss, nations will need to address these root causes. Growth in demand for food and housing, each rooted in population growth, has contributed to the loss of biodiversity. Both the conversion of species-rich forests and wetlands to cropland and the increasing intensity of fertilizer and pesticide use are major factors in the extinction of species, and they are direct responses to increases in food demand. Suburban sprawl and urban concentration also increasingly contribute to habitat loss and degradation.