El Niño Southern Oscillation.
Or ENSO.
ENSO is a pattern of trade winds and ocean temperatures
in the eastern tropical Pacific that impacts global climate.
It has three phases:
El Niño, La Niña and neutral, shifting between them every few years.
Weaker trade winds during El Niño
allow warm water to pile up in the eastern tropical Pacific.
This warming ocean temperature tends
to drive warmer temperatures globally and wetter conditions in the southern U.S.
La Niña acts like El Niño’s reverse.
Stronger trade winds keep the eastern tropical Pacific cool,
driving cooler global temperatures and a drier southern U.S..
We've been experiencing a rare triple dip or three years of La Niña, impacting
drought in the American Southwest and producing slightly
cooler global temperatures than we might expect otherwise.
ENSO’s minor effects on global temperature are one reason the past few years
have been slightly cooler than 2020 or 2016 -- El Niño years.
However, temperature shifts ENSO brings aren't nearly as significant
as the global pattern of warming caused by humans.
In fact, current La Niña -- cooler -- years are warmer than previous El Niño
-- warmer -- years.
With or without ENSO, warming on Earth is here and we are causing it.