A new satellite view shows ocean heights rising in the Pacific, another telltale sign of El Niño.
On Tuesday, NASA’s Earth Observatory released a map showing ocean heights in the tropical Pacific in early May compared to May 1997, the year an El Niño formed against which all other El Niños are measured. That year’s El Niño helped fuel extreme weather around the globe and contributed to 1998 being one of the warmest years in recorded history.
NASA’s image shows that while El Niño conditions haven’t yet formed, this year is following a trajectory similar to 1997.
El Niño is generally defined by an abnormal tongue of hot water stretching from the coast of South America into the Pacific Ocean. Currently, ocean surface temperatures in that region have been slowly warming, but they aren't close to El Niño levels yet.
The related measure of ocean height provides another way to look at El Niño and the conditions that precede it, and NASA’s satellites have captured a rise of water in the eastern Pacific. The map above shows areas where the ocean is higher than normal in reddish brown and lower than normal in green. The maximum rise is only about an inch off the coast of Central and South America, but that tiny tweak is a hint of bigger things underway.