La Nina : Concern
Climate change is intensifying, and the cooling effects of La Niña may weaken in a warmer future, climate scientists warn, citing current heat trends across much of the country.
- La Niña is a climate pattern that describes the cooling of surface-ocean waters along the tropical west coast of South America.
- It is considered to be the counterpart to El Niño, which is characterized by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean.
- Together, La Niña and El Niño are the “cold” (La Niña) and “warm” (El Niño) phases of the El Nino-Southern Oscillation (ENSO). ENSO is series of linked weather- and ocean-related phenomena.
- La Niña events are indicated by sea-surface temperature decreases of more than 0.5 degrees Celsius (0.9 degrees Fahrenheit) for at least five successive three-month seasons.
- La Niña is caused by a build-up of cooler-than-normal waters in the tropical Pacific, the area of the Pacific Ocean between the Tropic of Cancer and the Tropic of Capricorn.
- Unusually strong, eastward-moving trade winds and ocean currents bring this cold water to the surface, a process known as upwelling. Upwelling can cause a drastic drop in sea-surface temperature.
