Ultramarine: the science of our oceans and waterways
Feb 13, 2026 · 19 min · 11 segments
Ocean currents are the hidden systems that regulate Earth’s climate, moving heat and energy around the planet. But as the ocean warms, those currents are beginning to shift, with major consequences…
Ellen PhiddianGuest
David BoldemanHost
How connected is the world's ocean system really? Are we talking, you know, one drop of water literally is doing a lap around the earth? And how long does that take?
But to go around the entire world at the speed that these ocean currents move, we're talking hundreds, thousands of years.
But it takes a really, really long time to sort of make its way through an entire revolution.
And so is it going to all parts of the world or are there some parts where the currents aren't as strong? How does that work?
Yeah, so there is kind of a broad system of ocean currents that are sort of followed around the world.
So all of the big ocean basins have what we call these ocean gyres, where ocean water tends to move towards the equator up the west side of the ocean.
We have these ocean gyres in all of the big ocean basins, so like the Indian Ocean, the Pacific Ocean, North Atlantic, the South Atlantic.
Along the eastern side of those basins, water tends to move up from the pole towards the equator or down from the pole towards the equator in the northern hemisphere.
And then down the other side, the western side, it tends to move down from the equator.
That doesn't happen absolutely everywhere in the world, but that is kind of one of the big things that happens.
You sort of see this clockwise or counterclockwise movement around these big ocean basins.
So for instance, in West Australia, there's a little warm current that's forced through Indonesia that goes down the West Coast, and that causes a lot more rain around Western Australia than you'd normally expect.
I can't say with certainty, like if you put a drop of dye in at this point in a thousand years, it's going to be on this ocean, on this continental shelf, but it is sort of very slowly moving.
And that's because back to the point of the, let's call it the red dye, because I'm just going to pick a color.
How connected is the world's ocean system really? Are we talking, you know, one drop of water literally is doing a lap around the earth? And how long does that take?
But to go around the entire world at the speed that these ocean currents move, we're talking hundreds, thousands of years.
But it takes a really, really long time to sort of make its way through an entire revolution.
And so is it going to all parts of the world or are there some parts where the currents aren't as strong? How does that work?
Yeah, so there is kind of a broad system of ocean currents that are sort of followed around the world.
So all of the big ocean basins have what we call these ocean gyres, where ocean water tends to move towards the equator up the west side of the ocean.
We have these ocean gyres in all of the big ocean basins, so like the Indian Ocean, the Pacific Ocean, North Atlantic, the South Atlantic.
Along the eastern side of those basins, water tends to move up from the pole towards the equator or down from the pole towards the equator in the northern hemisphere.
And then down the other side, the western side, it tends to move down from the equator.
That doesn't happen absolutely everywhere in the world, but that is kind of one of the big things that happens.
You sort of see this clockwise or counterclockwise movement around these big ocean basins.
So for instance, in West Australia, there's a little warm current that's forced through Indonesia that goes down the West Coast, and that causes a lot more rain around Western Australia than you'd normally expect.
I can't say with certainty, like if you put a drop of dye in at this point in a thousand years, it's going to be on this ocean, on this continental shelf, but it is sort of very slowly moving.
And that's because back to the point of the, let's call it the red dye, because I'm just going to pick a color.
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