Even The Currents in The Ocean's Depths Can't Escape The Effects of Climate Change

We know that global warming affects ocean currents in a variety of ways, but there are still questions about how this relationship works. A new study tries to answer some of the questions.

Scientists pored over 66 million years of data to figure out the strength of ocean currents and how they relate to temperature changes.

Doing so provided a lot of extra data beyond the 30 years or so of satellite imagery that researchers traditionally used to look at how ocean current activity changes as the temperature of the globe keeps on rising.

The satellite data typically used to inform ocean models only cover a few decades, which leads to a poor understanding of long-term ocean variability, according to a University of Sydney researcher.

We looked at the deep-sea geological record to understand the changes.

The team found that the hiatuses in the record became less frequent as the Earth cooled down. The current speed in the deepest parts of the ocean has slowed down.

Deep ocean circulation appeared to be more busy during the hothouse climate that preceded the cooling-off era. At this time, global temperatures would have been 3-4 degrees warmer than they are today.

You don't have to live on the sea bed to be affected by fluctuations in ocean currents.

A break in sedimentation indicates vigorous deep-sea currents, while continuous sedimentation indicates calmer conditions, says Dietmar Müller from the University of Sydney.

Combining these data with reconstructions of ocean basins has allowed geologists to track where and when the breaks occurred.

The more we know about the past, the better our predictions will be when it comes to modeling how global warming will change the oceans in the future. Excess carbon and heat have already been soaked up by the ocean.

In periods of climate warming, the oceans can trap more carbon by using dissolved carbon to build their shells and then drifting down to the ocean floor after death.

As temperatures on Earth continue to rise, there will be more activity down in the depths of the oceans. Future research will have to assess how that will affect the balance of life and atmosphere.

Studies using satellite data suggest that large-scale ocean circulation and ocean eddies have become more intense over the last two to three decades of global warming.

The research has been published.