Heat waves are hitting older adults harder than ever, with heat-related deaths among people 65 and older jumping 85% since the 1990s as extreme temperatures become the new normal around the world, the UN Environment Programme (UNEP) warned today.
The latest Frontiers 2025 Report shows that older adults—especially those with chronic illnesses, limited mobility, or frailty—face serious health risks from heat waves, including breathing problems, heart disease, and other disorders that can be deadly. The report comes as communities across China, Japan, India, Europe, the US, and elsewhere face weeks of extreme heat and flooding. UNEP Executive Director Inger Andersen said heat waves are among the most frequent and deadly impacts of climate change, and the world must be prepared for the risks they pose to society’s most vulnerable people.
Older adults now make up a growing share of the world’s population, particularly in urban areas of low- and middle-income countries. They face extra risks from worsening air quality and floods in low-lying coastal cities where many live. The report calls for making cities pollution-free, resilient, and accessible with lots of green spaces. Key strategies include better urban planning, community-based disaster risk management, and improved access to climate information for older populations. Earlier this year, the UN Human Rights Council adopted a new resolution to develop an international legally binding instrument on the human rights of older persons, which could help protect those most exposed to climate change.
But older adults aren’t the only ones at risk. The report warns of other troubling climate impacts, including ancient microbes awakening as glaciers melt. If global temperatures rise more than 2°C above pre-industrial levels, this would shrink the cryosphere—glaciers, seasonal snow, ice sheets, sea ice, and permafrost—putting 670 million people at risk. Dormant fungi, bacteria, and viruses in these frozen regions could reactivate, raising the risk of antimicrobial resistance.
Floods are also stirring up toxic chemicals that were banned decades ago but have built up in sediment over centuries. As floodwaters churn up sediment and debris, these toxic chemicals get released and can re-enter urban areas or food systems. The report suggests traditional flood control measures like dikes and retention basins, improved drainage systems, nature-based solutions like sponge-city approaches, and regular monitoring of pollutants.
The report also points to the risk of aging dams, which can harm indigenous and fishing-dependent communities while degrading ecosystems. Europe and North America are increasingly removing large, older dams that have become unsafe, obsolete, or economically unviable. The report shows how dam removal can restore natural river connectivity for biodiversity and ecosystems, reversing river fragmentation and restoring natural processes.
