Climate Cycles Link Floods and Droughts Worldwide

Scientists who track Earth's water levels from space have uncovered a clear link between major climate cycles and water extremes around the world. El Niño and La Niña events, which shift sea temperatures in the Pacific Ocean, are causing floods and droughts to happen at the same time in regions thousands of miles apart. This discovery, based on two decades of satellite data, points to a global pattern in water crises that has grown stronger in recent years.

Background

El Niño and La Niña are part of a natural climate pattern called ENSO, or El Niño-Southern Oscillation. El Niño happens when waters in the central and eastern Pacific warm up more than usual. La Niña follows when those same waters cool down. These shifts change weather patterns across the globe, often leading to heavy rains or long dry spells in different places.

For years, researchers watched how these events affected local areas. Australia might flood during one La Niña while parts of South America dry out. But until now, no one had connected the dots on a worldwide scale. Teams from places like the University of Texas at Austin used satellites to measure total water storage on land—everything from soil moisture to groundwater and lakes. They looked at data from 2003 to 2023, covering many ENSO cycles.

This work builds on earlier studies that tied ENSO to regional weather. In the past, La Niña brought too much rain to southeast Asia and Australia but drought to the Horn of Africa and South America. El Niño did the opposite in many spots, soaking the Americas while drying out places like India and Indonesia. The new findings show these effects ripple out much farther, hitting continents together.

Key Details

The researchers found that strong ENSO events push water levels to extremes in far-off regions at once. During El Niño years, some areas get bone-dry while others drown in rain. The patterns flip for La Niña.

Take the mid-2000s El Niño: South Africa saw extreme dryness, and the pattern matched dry spells elsewhere. In 2015-2016, another El Niño hit the Amazon hard with drought. La Niña in 2010-2011 brought floods to Australia, southeast Brazil, and South Africa all at the same time.

The Global Shift Around 2011

Data showed a big change about a decade ago. Before 2011, wet extremes outnumbered dry ones across the planet. After 2012, dry conditions took over as the main problem. This flip lines up with a long-term pattern in the Pacific that amps up ENSO's drying effects.

ENSO now drives most water extremes worldwide. When these cycles get intense, they override local weather and sync up disasters. Satellites caught this by tracking changes in water storage month by month, continent by continent.

"ENSO has a synchronizing effect on water storage extremes across continents," said a lead researcher involved in the study.

Right now, a weak La Niña hangs on, with signs it will fade by early 2026. Forecasts point to neutral conditions through spring, then a possible El Niño by summer. That could mean more wet weather in the southern U.S. and drought risks in India and other spots.

What This Means

Water shortages and floods no longer stand alone. They connect through these ocean cycles, making planning harder for farmers, cities, and governments. In farming areas like the U.S. Corn Belt or India's monsoon zones, a synced dry spell could cut crop yields everywhere at once.

Dry extremes now dominate, raising risks for drinking water, rivers, and ecosystems. Places like the Amazon and Horn of Africa already feel this, with droughts lasting years. As the planet warms, even weak ENSO events pack more punch, blending with heat to worsen fires, crop failures, and migration.

Governments watch Pacific sea temperatures closely. A coming El Niño in 2026 could flood the U.S. South while starving rains in Asia. Neutral phases bring steadier weather, but the long-term trend toward dryness means building reservoirs, smart farming, and early warnings matter more.

This global view changes how we fight water crises. Aid groups now see patterns linking Africa’s droughts to South America’s. Cities from California to eastern China prepare for linked risks. The satellite data keeps updating, tracking if dry spells keep winning out.