Oliver Steeds reveals how much we really know about our oceans

Uh, I think it's probably true in some regard.

Uh, I think, you know, why it's the case is relatively simple.

To go to Mars is, um, uh, is something which we can do in terms of from a mapping exercise.

And to map Mars, we need satellites, um, and the satellites can punch through, uh, you know, the atmosphere that's there to be able to give us a, a readout on what's there on the surface.

When we come to planet Earth or planet ocean, 71% of it's covered by the sea, and satellites have a lot of trouble actually getting through water.

Um [clears throat] and so as things stand, I think something like 30%, which is protect- uh, which is mapped already.

Um, but also we know that there's probably another 20, 30%, uh, which is already mapped, which is data held by businesses and commerce and governments and military.

So that's a key part of why we haven't m- mapped all of it, because we kinda have mapped quite a chunk of it, but we don't have access to that data.

We have the technology to do all the mapping.

Um, so ultimately it comes down to, um, the motivation to do it, which is what's undermining our efforts to be able to fully map it.

But when it comes to, you know, I think in order to have a conversation about the future, you have to go back in time a little bit, and I think as I would, I would guess that the history of kind of ocean mapping is w- how far across do we have to go to get to land? Where is the land? N- For, it's only fairly recently in human history that we've started to consider going down and understanding what's underneath and why.

How long ago did we start doing that, and why is it necessary? What's the point of mapping the ocean?

Um, well, we started m- modern marine science with the Challenger expeditions in the 1870s.

Um, and so that's when they started to get ocean depths, and that was just with a lead line.

So that's where Challenger Deep, the deepest part of the ocean, came from, from the HMS Challenger expeditions, dropping a lead line down there and going, "Whoa, it's about seven miles down." Um, [clears throat] but obviously technology has advanced significantly from, from that point.

Um, so we now have the tech that we can, we can map the full ocean depth to extraordinary resolution, as we've seen with the Five Deeps Expedition, for example, which mapped the trenches, which is in the hadal zone from about 6,000 to 11,000 meters down.

But that's only a very small percentage of, of, uh, the seabed.

That's 1 or 2%.

Um, so we can do it.

Um, the average depth is 4,000 meters of the ocean as well.

So, you know, to get good maps, you need to have some good tech, which just tends to be mounted on the hulls of large vessels, either, uh, commercial vessels, military or science vessels, um, to be able to gather that map, that information.

And I, I ask this question with genuine sincerity.

I, you know, I'm-- as I said to you before we recorded, this is not my area of expertise.

I won't pretend it is.

But what is the point? What is down there? Why, outside of curiosity, which I would argue is a good reason anyway-