Nature Depletion: Fewer People, Better Outcomes?
Since the early 2000s, an ambitious initiative has brought together hundreds of citizen scientists collecting biodiversity data for Japan’s Monitoring Sites 1,000 project. This massive undertaking has amassed 1.5 million species observations from 158 varied locations across the nation, providing a unique window into the ongoing changes in biodiversity.
Globally, since the 1970s, we’ve seen a staggering 73% decline in wildlife, coinciding with the doubling of the human population to 8 billion. This correlation hints at a grim reality: rapid population growth is taking a severe toll on biodiversity. However, as we look ahead, we stand at the cusp of a significant shift in human demographics, potentially influencing environmental outcomes positively.
Projections by the United Nations suggest that by 2050, we could see population declines in 85 countries, particularly in Europe and Asia. Extended to 2100, the trend points towards a global demographic downturn, leading some to speculate about the environmental benefits this could usher in.
Japan leads as the first Asian nation to experience depopulation starting in 2010, with South Korea, China, and Taiwan following suit. In southern Europe, Italy initiated this shift in 2014, followed by Spain, Portugal, and others. Termed “depopulation vanguard countries,” Japan and Italy serve as pioneering case studies to evaluate the potential environmental impacts of decreasing human numbers.
Inquiries into whether Japan might be experiencing a biodiversity “depopulation dividend” have been underway, led by a team investigating these dynamic interactions. Using extensive data on sightings of birds, butterflies, fireflies, frogs, and nearly 3,000 plant species (both native and non-native), researchers correlated biodiversity records from the Monitoring Sites 1,000 with changes in local populations, land use, and temperatures over spans of five to two decades. These landscapes have been notably influenced by depopulation trends since the 1990s.
Japan’s Unique Narrative
The research reveals that biodiversity continued to diminish in most studied areas, regardless of whether the human population was rising or falling. Notably, in places where population figures remained stable, biodiversity fared better. However, these regions are marked by an ageing demographic, predicting future declines aligning them with areas already experiencing biodiversity losses.
Japan’s population decrease contrasts starkly with the Chernobyl scenario, where a sudden evacuation led to unexpected wildlife resurgence. Instead, Japan’s gradual shifts create a complex pattern of alternating land uses amid communities that still function. While a majority of farmland persists in cultivation, sections become either abandoned, repurposed for urban expansion, or converted into intensively farmed zones, limiting the potential for natural ecosystems to regenerate and thrive.
In these settings, humans play a crucial role in ecosystem stability. Traditional practices including rice farming, orchard care, and land maintenance contribute significantly to sustaining biodiversity. Contrary to aiding nature, depopulation potentially threatens it. Some species may flourish, but often these are non-native, bringing their own ecological challenges, such as invasive grasses overtaking formerly water-rich rice fields.
Challenges are compounded by increasing numbers of abandoned houses, intricate socio-legal obstacles, and continued new construction in response to shifting domestic demographics and needs. Despite fewer inhabitants, wildlife finds itself with shrinking habitats.
Charting a Course Forward
With Japan and northeast Asia deeply into depopulation phases, and fertility rates continuously low in many developed regions, confronting this demographic shift becomes unavoidable. Immigration offers only temporary relief, as many current source countries for migrants, like Vietnam, are also moving towards demographic downturns.
Efforts geared towards biodiversity recovery, especially in areas undergoing depopulation, need active management. Rewilding initiatives are scarce in Japan, yet there is potential for local authorities to lead by transforming unused lands into community-managed conservation areas. Consideration of ecological risks—such as dwindling fish stocks and rampant deforestation—demands greater accountability from both government and business sectors.
Reevaluating infrastructure spending for a population in decline offers an opportunity; funds could be rededicated to nurturing local forests, thus generating carbon credits and ecological benefits. As depopulation evolves into a defining global trend of the 21st century, it presents a unique chance to address some of the most pressing ecological challenges. However, seizing this opportunity requires deliberate and proactive management.
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