It’s coming. Winds are weakening along the equatorial Pacific Ocean. Heat is building beneath the ocean surface. By July, most forecast models agree that the climate system’s biggest player – El Niño – will return for the first time in nearly four years.
El Niño is one side of the climatic coin called the El Niño-Southern Oscillation, or ENSO. It’s the heads to La Niña’s tails.
Life in the southwestern U.S. as we know it exists thanks to the water of the Colorado River, which flows for approximately 1,450 miles from the Rockies to the Gulf of California.
The river gets its water from the Colorado River drainage basin, which spreads some 246,000 square miles.
The term La Niña may be one that casual weather observers as well as aficionados hear meteorologists using from time to time, especially when breaking down long-term weather trends or providing a sneak peek at conditions expected during an upcoming winter or hurricane season. But, what exactly is La Niña? Let’s take an in-depth look.
The key to how winter in the United States may unfold often lies thousands of miles away in the open waters of the equatorial Pacific Ocean. It’s there where the roots of a climatological phenomenon known as La Niña originate and eventually help shape weather patterns worldwide.
There isn’t a one-size-fits-all approach to forecasting climate patterns when there’s an El Niño or a La Niña pattern in place.
El Niño and La Niña patterns are part of the El Niño Southern Oscillation, which monitors sea-surface temperatures in the equatorial Pacific Ocean.
When sea-surface temperatures in this region are above average, it’s called El Niño; when they are below average, it’s called La Niña.
We aren’t talking about major changes in water temperatures but typically more minor swings — usually on the order of plus or minus a degree Celsius — 1.8 degrees Fahrenheit — or less.
There are instances when water temperatures have been as much as eight degrees Fahrenheit above average — a very strong El Niño — but it’s not common.
The amount and location of available terrestrial water is changing worldwide. An international research team led by ETH Zurich has now proved for the first time that human-induced climate change is responsible for the changes observed in available terrestrial water.
Across much of the United States, the flood risk is far greater than government estimates show, new calculations suggest, exposing millions of people to a hidden threat — and one that will only grow as climate change worsens.
