Global distribution of carbonate rocks and karst water resources

TLDR

Karst regions provide freshwater, biodiversity, and cultural resources, and the World Karst Aquifer Map is the first comprehensive global geodatabase of karstifiable rocks. The study aims to evaluate the World Karst Aquifer Map for carbonate rock karst, addressing global occurrence, topography, climate, and population distribution. The authors conduct a statistical analysis of WOKAM data, focusing exclusively on carbonate rock karst. The analysis shows that 15.2 % of the ice‑free continental surface is karstifiable carbonate rock, with Europe having the highest percentage (21.8 %) and Asia the largest area (8.35 million km²), and that 1.18 billion people (16.5 % of the global population) live on karst, underscoring its global importance for water management.

Abstract

Abstract Karst regions offer a variety of natural resources such as freshwater and biodiversity, and many cultural resources. The World Karst Aquifer Map (WOKAM) is the first detailed and complete global geodatabase concerning the distribution of karstifiable rocks (carbonates and evaporites) representing potential karst aquifers. This study presents a statistical evaluation of WOKAM, focusing entirely on karst in carbonate rocks and addressing four main aspects: (1) global occurrence and geographic distribution of karst; (2) karst in various topographic settings and coastal areas; (3) karst in different climatic zones; and (4) populations living on karst. According to the analysis, 15.2% of the global ice-free continental surface is characterized by the presence of karstifiable carbonate rock. The largest percentage is in Europe (21.8%); the largest absolute area occurs in Asia (8.35 million km 2 ). Globally, 31.1% of all surface exposures of carbonate rocks occur in plains, 28.1% in hills and 40.8% in mountains, and 151,400 km or 15.7% of marine coastlines are characterized by carbonate rocks. About 34.2% of all carbonate rocks occur in arid climates, followed by 28.2% in cold and 15.9% in temperate climates, whereas only 13.1 and 8.6% occur in tropical and polar climates, respectively. Globally, 1.18 billion people (16.5% of the global population) live on karst. The highest absolute number occurs in Asia (661.7 million), whereas the highest percentages are in Europe (25.3%) and North America (23.5%). These results demonstrate the global importance of karst and serve as a basis for further research and international water management strategies.