THE FORECAST that future wars will be fought over water has been made long enough for it to become both a platitude and subject to doubt. Demand for water has surged because populations have grown and rising prosperity has enabled them to live more water-intensive lives. But supply of the wet stuff is already coming under ever greater pressure, as climate change, crudely put, makes dry places drier.

Yet the great water-based conflicts that were feared—India v Pakistan, Ethiopia v Egypt, Brazil v Paraguay, China v any of the countries downstream from the Himalayas—have not come to pass. Maybe, argue optimists, the world is better at sharing this resource than is often assumed.

This complacent argument ignores two truths apparent from the latest update to the Water Conflict Chronology, a database of water-related conflicts maintained since the 1980s by the Pacific Institute, a think-tank in Oakland, California. First, for as long as human history has been recorded, water has played a role in conflict, even though it has rarely been the sole cause of it. Second, water-related struggles are becoming far more common. Its database includes over 900 instances, and shows a clear acceleration in recent years.

The institute distinguishes between three types of violence. Sometimes water itself can be used as a weapon, as when the Spartans poisoned the drinking water in Athens in the second year of the Peloponnesian war, in 430BC. Or, just last year, al-Shabaab, a terrorist group, diverted water from the Jubba river in Somalia, causing a flood that forced opposing forces to move to higher ground, where they were ambushed.

Sometimes water is the trigger. Fighting over grazing land in central Mali this year has led to massacres and the displacement of 50,000 people. Ariel Sharon, an Israeli commander in the six-day war of 1967 who went on to become prime minister, wrote that the war really started when Israel was provoked by the diversion of the Jordan river.

Third, water installations can also be the target of military action. The institute notes that the large number of new additions to its chronology results in part from more comprehensive data collection. But it also reflects a big increase in attacks on civilian water systems. Indeed, almost wherever there has been warfare this year, water installations have been in the cross-hairs—in Syria, Ukraine and Yemen, for example.