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The Indo-Pacific Warm Pool shown in orange. Credit: NASA
The world’s biggest hot tub isn’t in Cancún or South Beach or even Las Vegas. Instead, it extends almost half-way around the world, from the east coast of Africa to the middle of the Pacific Ocean. The water in the heart of this band peaks at about 86 degrees Fahrenheit, making it the warmest ocean water on the planet.This giant hot tub is the Indo-Pacific Warm Pool. It encompasses a large part of the Indian Ocean plus a much smaller part of the Pacific. But its influence extends far beyond that — it impacts the climate of much of the world.
It does so because the warm water at the surface evaporates, carrying heat and moisture high into the atmosphere. The moisture forms clouds that are driven by high-level winds, bringing rainfall to some regions but keeping it away from others.
Which regions get the rain depends in part on the size of the warm pool, which varies by millions of square miles over a period of a couple of decades. When it’s bigger, Australia and South America see drier winters. And when it’s smaller, regions from the Mediterranean Sea to the Pacific Northwest see wetter summers.
Overall, the warm pool has grown larger and warmer over the last few decades — a likely result of global climate change. That could bring drought conditions to parts of Africa, create stronger hurricanes in the Atlantic Ocean, and even have an effect on the length and intensity of El Niño events. So the changes in this hot tub are no party — they can have serious consequences for much of the planet.
