Study: Ocean tides once spread massive icebergs

December 8, 2004

Connection between changes in ocean circulation and future climate remains a matter of great interest

Labrador Sea ocean tides dislodged huge Arctic icebergs thousands of years ago, carrying gigantic ice-rafted debris across the ocean and contributing to the ice age's deep freeze, say an international team of university researchers.
The study, published in the November issue of Nature, is the first to suggest that ocean tides contributed to enigmatic Heinrich events, a phenomenon where colossal discharges of icebergs periodically flowed into the North Atlantic from about 60,000 to 10,000 years ago.

The events occurred during the deep throes of the ice age and the new study shows that tides added to the chill by breaking gigantic icebergs from the ice sheet covering northern Canada. “These findings provide a link between ocean tides, ice sheets and ocean circulation and a measure of the sensitivity of climate during the last ice age,” says University of Toronto physics professor Jerry Mitrovica, a co-author of the study. “This sensitivity is important to understand, because the connection between changes in ocean circulation and future climate remains a matter of great interest.”

To track ancient tides, Mitrovica, lead author Professor Brian Arbic of Princeton University and a team of researchers used a state-of-the-art computer model that captured current open-ocean tidal variances with an unprecedented 92 per cent accuracy. They then inputted ice-age simulations of sea-level changes over time. “The results showed that the tides were highest in the Labrador Sea at the same time the Heinrich events occurred,” says Mitrovica. “We can safely assume that the tides played a key role in breaking the ice and launching the icebergs into the ocean.”

Mitrovica is careful to note that ocean circulation is just one piece of the present-day climatic change puzzle. “As an example, the Antarctic ice sheet weakens due to warming and huge blocks have broken off where tides are highest. Future climatic changes involve many different factors, but it's important to note that in our ice-age past tides defined the weak spot and acted as a catalyst for large climate events.”

The study was funded by National Sciences Foundation and the Canadian Institute for Advanced Research. Other authors include Professor Douglas MacAyeal of the University of Chicago and Glenn Milne of the University of Durham, United Kingdom.

Source: University of Toronto

Explore further: Climate change: Warm water is mixing up life in the Arctic

Related Stories

Climate change: Warm water is mixing up life in the Arctic

November 20, 2015

The warming of arctic waters in the wake of climate change is likely to produce radical changes in the marine habitats of the High North. This is indicated by data from long-term observations in the Fram Strait, which researchers ...

Jupiter's moon Europa

September 30, 2015

Jupiter's four largest moons – aka. the Galilean moons, consisting of Io, Europa, Ganymede and Callisto – are nothing if not fascinating. Ever since their discovery over four centuries ago, these moons have been a source ...

The moon

September 21, 2015

Look up in the night sky. On a clear night, if you're lucky, you'll catch a glimpse of the moon shining in all it's glory. As Earth's only satellite, the moon has orbited our planet for over three and a half billion years. ...

Extreme Pacific sea level events to double in future

September 25, 2015

Many tropical Pacific island nations are struggling to adapt to gradual sea level rise stemming from warming oceans and melting ice caps. Now they may also see much more frequent extreme interannual sea level swings. The ...

Recommended for you

Roboticists learn to teach robots from babies

December 1, 2015

Babies learn about the world by exploring how their bodies move in space, grabbing toys, pushing things off tables and by watching and imitating what adults are doing.

Getting into the flow on the International Space Station

December 1, 2015

Think about underground water and gas as they filter through porous materials like soil and rock beds. On Earth, gravity forces water and gas to separate as they flow through the ground, cleaning the water and storing it ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.