Melting Ice, Rising Risks: UN’s Chilling Climate Call
Nairobi: As relentless heat waves, devastating floods, and a rapidly thawing cryosphere grip communities across China, Japan, India, Europe, the USA, and beyond, the UN Environment Programme (UNEP) has issued a dire warning about the escalating threats posed by climate change, particularly to older persons and fragile ecosystems. The Frontiers 2025 Report, titled The Weight of Time – Facing a new age of challenges for people and ecosystems, released today, highlights the alarming risks of extreme heat, which has become “the new normal,” alongside the reactivation of ancient microorganisms due to melting glaciers and permafrost, and the release of long-banned toxic chemicals through floods. This seventh edition of the report, part of UNEP’s Foresight Trajectory initiative, underscores emerging environmental threats while proposing actionable solutions to safeguard vulnerable populations and ecosystems. Notably, the report’s first edition in 2016 warned of rising zoonotic disease risks, four years before the COVID-19 pandemic, underscoring its prescience.
The report draws urgent attention to the vulnerability of adults aged 65 and above, who form a growing segment of the global population, particularly in urban areas of low- and middle-income countries. Heat waves, among the most frequent and deadly consequences of climate change, have driven an estimated 85% surge in heat-related deaths among older persons since the 1990s. Those with chronic illnesses, limited mobility, or frailty face heightened risks of respiratory, cardiovascular, and metabolic diseases, alongside increased mortality. Deteriorating air quality and flooding in low-lying coastal cities, where many older persons reside, further exacerbate these dangers. To address this, the report advocates transforming cities into pollution-free, resilient, and accessible spaces through better urban planning, expansive vegetation, community-based disaster risk management, and improved access to climate information tailored for older populations. Earlier this year, the UN Human Rights Council adopted a resolution to develop an “international legally binding instrument on the human rights of older persons,” offering a potential framework to enhance protections for those most exposed to climate impacts.
The report also raises grave concerns about the thawing cryosphere, which has lost an astonishing 28 trillion tonnes of ice between 1994 and 2017, with the rate of ice loss accelerating by 57% over those 24 years. Projections indicate that by 2100, the world’s glaciers could be halved, even if global temperature rise is limited to 1.5°C above pre-industrial levels, while 24 to 69% of near-surface permafrost is expected to thaw. Glaciers are no longer merely shrinking—they are vanishing. This rapid cryosphere warming is reactivating and remobilising modern and ancient microorganisms into new terrestrial and aquatic environments. A 2022 estimate suggests that 2.9 x 10^22 microbes will be discharged annually into downstream ecosystems in the Northern Hemisphere over the next 80 years due to glacier melting. Some cryospheric microorganisms may not survive the thaw, leading to a loss of microbial diversity and valuable genetic information, while others could thrive, profoundly altering the structure and function of existing microbial communities and surrounding ecosystems.
The reactivation of ancient pathogens poses a particularly alarming threat. Research indicates that some re-emerging microbes could infect plants, animals, and humans. For instance, in the 1990s, coliform bacteria up to 2,000 years old were isolated from Canadian Arctic ice samples. In 2015, researchers reactivated Bacillus anthracis strains from sediment layers in Siberia’s Yakutia region, deposited since the 1300s. A 2016 anthrax outbreak in Russia’s Yamal region, which killed over 2,000 reindeer and hospitalised 90 herders, was linked to permafrost thaw and abnormally high summer temperatures that likely reactivated B. anthracis in soil reservoirs. Fungi with pathogenic potential have also been isolated from cryospheric habitats, and a 2023 experiment successfully reactivated 13 new viruses from Siberian permafrost, demonstrating their ability to infect Acanthamoeba hosts. While widespread outbreaks are unlikely, scientists are intensifying efforts to assess the threat of these ancient pathogens.
Compounding these risks is the transfer of virulence-related and antibiotic-resistance genes through horizontal gene transfer, a process unique to the microbial world where genetic material moves between unrelated species. Researchers have detected thousands of virulence factors in microorganisms from 21 Tibetan glaciers, alongside antibiotic-resistance genes in pristine frozen areas and ancient ice-core samples, some preserved for thousands or even millions of years. This “genome recycling” could accelerate microbial evolution, potentially creating new strains with higher virulence. Cryospheric microorganisms, known as psychrophiles, are adapted to thrive in extreme cold through strategies like producing antifreeze compounds, synthesising molecules to enhance membrane fluidity, and entering dormant states. Their cold-active enzymes have significant biotechnological applications, used in industries for producing pharmaceuticals, food, beverages, detergents, and high-quality chemicals. Psychrophilic enzymes also aid in developing antimicrobials, organic polymers, and biofertilizers, while providing insights into the evolution of life on Earth and the potential for extraterrestrial life in icy environments.
The report further warns of the remobilisation of banned chemicals, phased out decades ago, which floods can unearth from centuries-old sediment. As floodwaters stir up debris, toxic chemicals risk contaminating urban areas or food systems. To mitigate this, the report recommends traditional control measures like polders, dikes, and retention basins, alongside improved drainage systems, nature-based solutions like sponge-city approaches, regular pollutant monitoring, and economic impact studies. The report also addresses the risks of ageing dams, which harm indigenous and fishing-dependent communities and degrade ecosystems. In Europe and North America, removing obsolete or unsafe dams is gaining traction, restoring natural river connectivity and supporting biodiversity. However, ecological recovery varies by region. Upstream, migratory fish rapidly recolonise newly accessible habitats, but non-native species may also spread. In former reservoir zones, draining leads to new river channels and pioneer vegetation, though sediment pulses can initially harm sensitive species. Downstream, resumed sediment flow supports habitat revival but requires careful management, especially for larger dams with significant sediment buildup. The success of dam removal depends on factors like the number of barriers, sediment type, and surrounding land use changes, with multiple stressors like urbanisation often limiting full restoration.
Inger Andersen, UNEP’s Executive Director, emphasised the urgency, stating, “Heat waves are among the most frequent and deadly impacts of climate change, along with floods and shrinking ice cover. We must be prepared for the risks these impacts pose, especially for society’s most vulnerable, including older persons. Yet as this year’s Frontiers Report shows, solutions exist that can help protect communities and restore ecosystems long thought to have been lost.” To slow cryosphere loss, the report urges cutting greenhouse gas emissions, including black carbon from diesel engines, agricultural burning, and wildfires, limiting tourism in fragile frozen regions, and exploring reflective geotextile sheets to shield glaciers, despite their high cost and environmental drawbacks. For permafrost, small-scale rewilding experiments with large grazers like bison and reindeer aim to harden snowpack but face scalability challenges. The report stresses the need for biobanks to preserve cryospheric microorganisms, whose genetic material could unlock therapies and biotechnologies while shedding light on climate history and microbial evolution. As global temperatures threaten to exceed the 1.5°C threshold by 2030, the report underscores the irreversible loss of stable ecological systems and the urgent need to manage these unavoidable consequences.
– global bihari bureau
