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, features the following chapters:
The frozen Pandora’s box: Reactivation of microbes in a warming cryosphere
For millennia, diverse microorganisms have remained dormant in the cryosphere - regions where water is frozen solid. Climate warming could reactivate and remobilize them into new environments, potentially altering microbial communities, introducing pathogens, or causing biodiversity loss as some might fail to survive thawing. This chapter explores these impacts, emphasizing the urgent need to preserve microbial biodiversity, as some species may aid in developing biotechnologies, disease therapies, and insights into climate and evolution.
Clearing the path: Barrier removal for river restoration
While dams have provided significant benefits, they have also disrupted indigenous and fishing communities while damaging river ecosystems. Removing dams and barriers is an increasingly accepted strategy to restore river health, and has gained momentum, particularly in Europe and North America, where large, older dams that have become unsafe, obsolete, or economically unviable are being removed. The practice has emerged as a vital strategy for ecological restoration -by reestablishing natural river connectivity, dam removal helps reverse ecosystem fragmentation, benefiting aquatic and terrestrial biodiversity while enhancing resilience against future environmental challenges.
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.
