Global water reserves and major cities face critical climate threats

The United Nations and the World Meteorological Organization (WMO) have issued warnings regarding a destabilizing global water cycle. The planet is experiencing an imbalance characterized by alternating periods of extreme water scarcity and excess. A decade-long decline in freshwater reserves—including groundwater, lakes, rivers, and soil moisture—is being exacerbated by rising global temperatures and the El Niño phenomenon.

Of particular concern is the rapid depletion of ‘slow reserves,’ such as glaciers and groundwater, which traditionally act as a buffer during droughts. Glaciers have seen significant mass loss across all regions for four consecutive years.

Simultaneously, rising sea levels and land subsidence are threatening major global metropolises. In New York, projections suggest tidal flooding could affect one in five streets in lower Manhattan by 2100. Venice faces increasing pressure on its MOSE barrier system as the Adriatic Sea rises, while Jakarta and Shanghai struggle with the dual threat of rising oceans and sinking land caused by groundwater extraction.