Roman fish tanks track ancient sea level

Sea level has barely changed in the last two thousand years, rising at an accelerating pace only in the past two decades or so.

Roman fish tanks in Cyprus, built at a precise level relative to high tide, show that sea level has barely changed in two millennia. As noted in the main story, seas have begun to rise detectably, and at an accelerating rate, only in the last two decades or so.Photograph by James Schutte/Alamy Stock Photo

Return to main article:

Geophysical proofs are not the only kinds of evidence Mitrovica marshals to illuminate the history of sea-level rise. One of his favorite examples comes from a fellow researcher at the Australian National University, Canberra. Kurt Lambeck, a professor of geophysics, has used 2,000-year-old Roman fish tanks to illuminate changes in sea level. In an era long before refrigeration, wealthy Romans built holding tanks beside their coastal villas so they could eat fresh fish whenever they wished. Sluice gates positioned with their tops eight inches above the high-water mark let seawater in and out, flushing the tanks with the natural ebb and flow of the tides. To work, they had to be built at a precise level relative to high tide.

Lambeck, after correcting for known geophysical influences such as the ongoing changes in Earth’s shape due to the ice age, showed that there has been virtually no change in sea level at these sites since the height of the Roman empire. The finding refutes climate skeptics’ claim that sea level has been rising continuously for a long time. Had the water been rising at two millimeters per year for two millennia, these tanks would today be under four meters of water. Lambeck’s work thus underscores the significance and implications of Mitrovica’s recent finding that sea level rise has accelerated dramatically in the past two decades.

Read more articles by Jonathan Shaw

You might also like

In Sermon, Garber Urges Harvard Community to ‘Defend and Protect’ Institutions

Harvard’s president uses traditional Memorial Church address to encourage divergent views.

A New Narrative of Civil Rights

Political philosopher Brandon Terry’s vision of racial progress

This Astronomer is Sounding a Warning on 'Space Junk'

As debris accumulates in low Earth orbit, the danger of destructive collisions continues to rise.

Most popular

Harvard art historian Jennifer Roberts teaches the value of immersive attention

Teaching students the value of deceleration and immersive attention

How MAGA Went Mainstream at Harvard

Trump, TikTok, and the pandemic are reshaping Gen Z politics.

Shakespeare’s Greatest Rival

Without Christopher Marlowe, there might not have been a Bard.

Explore More From Current Issue

David McCord in suit reading a book at cluttered wooden desk in office filled with framed art and shelves.

The Pump Celebrates Its 85th Birthday

Giving Harvard traditions their due 

Man in gray sweater standing in hallway with colorful abstract art on wall.

How Do Single-Celled Organisms Learn and Remember?

A Harvard neuroscientist’s quest to model memory

James Muller in white lab coat leaning on railing in hospital hallway.

Free Speech, the Bomb—and Donald Trump

A Harvard cardiologist on the unlikely alliances that shaped a global movement to prevent nuclear war