Climate’s effect on Pacific sea levels comes via another ocean

A NOAA tide gauge.

NOAA

A new study examines sea level changes in the tropical Pacific Ocean with the aim of determining how much of its rise is due to anthropogenic causes.

Part of the challenge of this work is that the Pacific experiences a natural oscillation in sea level that is caused by the Pacific Decadal Oscillation (PDO), a decade-long cycle in ocean currents and temperatures. The length of the PDO makes it difficult to distinguish an overall long-term pattern (if such a pattern exists) from the short-term variability.

Added to this is the fact that accurate sea level measurements, taken using satellite altimetry, only go back as long as we’ve been using satellites—a few decades.