Fewer people doesn’t always mean better outcomes for nature – just look at Japan

Since 1970, 73% of global wildlife has been lost, while the world’s population has doubled to 8 billion. Research shows this isn’t a coincidence but that population growth is causing a catastrophic decline in biodiversity.

Yet a turning point in human history is underway. According to UN projections, the number of people in 85 countries will be shrinking by 2050, mostly in Europe and Asia. By 2100, the human population is on course for global decline. Some say this will be good for the environment.

In 2010, Japan became the first Asian country to begin depopulating. South Korea, China and Taiwan are following close behind. In 2014, Italy was the first in southern Europe, followed by Spain, Portugal and others. We call Japan and Italy “depopulation vanguard countries” on account of their role as forerunners for understanding possible consequences in their regions.

Biodiversity continued to decrease in most of the areas we studied, irrespective of population increase or decrease. Only where the population remains steady is biodiversity more stable. However, the population of these areas is ageing and will decline soon, bringing them in line with the areas already seeing biodiversity loss.

While most farmland remains under cultivation, some falls into disuse or abandonment, some is sold for urban development or transformed into intensively farmed landscapes. This prevents widespread natural succession of plant growth or afforestation (planting of new trees) that would enrich biodiversity.