A warmer world is expected to produce more intense rainfall, but a new study suggests that doesn’t necessarily translate into more usable water.

Researchers reporting in Nature found that rainfall across much of the world has become increasingly concentrated into larger storms separated by longer dry periods. While annual precipitation may remain stable—or even increase—the new pattern can actually leave soils, vegetation, and groundwater drier over time.

The international research team analyzed global precipitation records from 1980 through 2022 using a statistical approach adapted from economics. Rather than focusing only on how much rain falls each year, they examined how evenly rainfall is distributed throughout the year.

Their conclusion is striking: when rain arrives in intense bursts, much of it runs off or evaporates before it can soak into the ground. Soil can absorb only so much water at once, leaving ecosystems with less moisture despite heavier storms.

The researchers project that if global temperatures rise by 2 degrees Celsius above preindustrial levels, roughly 27% of the world’s population could experience abnormally dry land conditions driven by increasingly concentrated rainfall—even in places where total precipitation increases.

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The study also found regional differences. Rainfall has become markedly more concentrated across much of the western United States and the Amazon Basin, while parts of northern Europe and Canada have experienced more evenly distributed precipitation, likely because warming has increased both rainfall and snowfall throughout the year.

According to the researchers, the findings suggest that water managers may need to rethink traditional assumptions about drought and flood risk. Communities could face both more destructive flooding during major storms and longer periods of water stress afterward as less moisture remains stored in the landscape.

The results do not suggest that climate change simply means either wetter or drier conditions. Instead, they point toward a more complicated future in which the timing and intensity of rainfall may become just as important as the total amount that falls. For regions already balancing flood control, agriculture, and shrinking water supplies, understanding that distinction could prove increasingly important.