Science News · Science

Southwest Megadrought: Causes and Uncertain Future

The American Southwest faces its driest period in 1,200 years, a megadrought since 2000 impacting communities like Kearny, Arizona, with severe water restrictions.

Scientists cite rising temperatures and declining precipitation, exacerbated by climate change, as causes. Some research suggests human emissions have disrupted the Pacific Decadal Oscillation (PDO), a natural climate cycle.

The Colorado River's flow is down 20% since 2000. Reservoirs are at historic lows, leading to federal water cuts for Arizona, California, and Nevada.

Tree ring data shows this is the most severe drought in over a millennium, characterized as a 'warm drought' due to rising temperatures.

The PDO influences regional weather. A cool phase, potentially prolonged by human emissions, favors drought in the Southwest.

Studies suggest human emissions have altered the PDO, potentially locking in drought for decades. The Southwest may face increasingly arid conditions.

Even if the PDO shifts, simulations indicate the region won't return to past wet conditions. Communities must improve water conservation for a drier future.

Kearny faces critical shortages as its water source reservoir is less than 1% full, threatening its supply.

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