Frontiers 2025: The weight of time: Facing a new age of challenges for people and ecosystems

The Frontiers Report spotlights emerging environmental issues before they escalate into global or regional crises. While these issues may currently appear localised or small-scale, early intervention is critical to prevent them from becoming widespread challenges.

The 2025 edition of the Frontiers report, The Weight of Time: Facing a new age of challenges for people and ecosystems, includes the following chapters:

• Demographic challenge: Growing old in a changing environment: the world is undergoing significant demographic and environmental shifts, with the global population aged 65 and older projected to increase from 10% in 2024 to 16% by 2050 - primarily in low- and middle-income countries. Concurrently, climate change is exacerbating environmental risks such as heatwaves, air pollution, and floods, which disproportionately threaten older adults. Since environmental conditions critically influence health in later life, proactive urban planning must prioritize age-friendly, resilient cities with reduced pollution, improved accessibility, and expanded green spaces to safeguard this vulnerable population.
• Forgotten but not gone: Remobilization of legacy pollutants by flood events: Many regions have faced an increase in the frequency and magnitude of severe storm events with extreme rainfalls and floods. While the direct effects of these floods on life and infrastructure are widely recognized, indirect outcomes are often overlooked. An underestimated issue is the remobilization and redistribution of chemical contaminants in river sediments by frequent and severe flooding, posing environmental challenges and socioeconomic repercussions.