厄尔尼诺：太平洋的海水变热，如何搅乱全球的天气？

Today, a term that's been in the news a lot lately — El Niño.

Many have heard the name but can't quite explain what it actually is.

Simply put, El Niño is the Pacific's water warming abnormally.

Let's start with where the name comes from — it's rather interesting.

Long ago, fishermen in Peru, South America, noticed the sea grew unusually warm every few years.

And it often happened around Christmas.

So they named it "the Christ child" — El Niño.

So why does the sea water warm up?

For that, we have to talk about the wind.

Normally, a steady wind over the Pacific keeps pushing warm water westward.

But every few years, this wind suddenly weakens.

Once the wind weakens, the warm water piled up in the west flows back east.

As the eastern water warms, the entire Pacific weather system goes haywire.

There's a detail here that really illustrates it.

Normally, cold water wells up from the deep off Peru's coast, bringing lots of fish.

When El Niño comes, warm water caps the top, the cold water can't rise, and the fish suddenly vanish.

Fishermen head out and often come back empty-handed.

That's exactly how the fishermen first noticed El Niño back then.

This upheaval affects not just the coast, but weather worldwide.

Some places get extreme rainfall, even major floods.

California, for one, tends to get hit by downpours and floods during a strong El Niño winter.

But other places fall into severe drought.

The Amazon, Australia, and parts of Africa may turn dry and hot, with crops unable to survive.

Beyond floods and droughts, El Niño has a bigger effect: it briefly makes the whole Earth hotter.

The globe is already warming, temperatures rising year by year.

Stack a strong El Niño on top, and this year and next may set new heat records.

That's why scientists are especially nervous this time.

According to their forecasts, this year's El Niño is likely to be very strong.

The numbers are alarming: about a 90% chance of reaching "strong" this year, and a 60% chance of hitting "super" level.

There's a strong chance it reaches "super El Niño" status.

If so, it could be the strongest in decades.

The last time it was this strong dates back nearly thirty years.

Of course, El Niño isn't all bad news.

For instance, it suppresses Atlantic hurricanes, making that storm season quieter.

But on balance, a strong El Niño brings more trouble than benefit.

Fortunately, unlike in the past, scientists can now forecast its arrival months ahead.

Knowing it's coming, countries can prepare earlier.

Like shoring up water systems in advance, or storing extra food and water.

There's another important point many people overlook.

When weather goes haywire, harvests shrink and food prices may rise.

In the end, El Niño affects every ordinary person's livelihood.

Ultimately, El Niño is no monster — just a natural fluctuation of Earth's climate.

But when it acts, the whole world has to adjust.

Okay, we've roughly laid out El Niño today; let's chat again next time.