"Polymetallic nodules are lumps of minerals that range in size from just a few millimeters to tens of centimeters and are found in the abyssal areas of the oceans basins of the world. Known deposits are found in various quantities around a water depth of 3500 to 6000 meters. They lie on a relatively flat seafloor of soft sediment in a large surface area. It is estimated that the nodules present in the Clarion Clipperton Fracture Zone (CCFZ) contain more nickel (Ni), manganese (Mn) and cobalt (Co) than all land-based reserves combined. Furthermore, they contain significant amounts of copper (Cu) and molybdenum (Mo) (1)."
* There's thought to be several regions of the seabed where the mining operation can basically just scoop up the top layer and get economically extractable ore out of it.
* The seabed is international waters, not under the jurisdiction of any country. I know UNCLOS does prescribe some rules for deep-sea mining, but it wouldn't surprise me if some of the ambitions for mining here were based off of being able to dodge undesired (from the mining companies' perspective) national rules around mining, such as taxes or environmental regulations.
* The ocean floor is a lot more of a dead zone than anything terrestrial. (That doesn't mean it's entirely dead). Again, I suspect many are hoping that environmental destructiveness in the seafloor goes much more unnoticed, because there's much less love for preserving microscopic Archaea species than fluffy birds or the like.
Is this a case where most people would expect nasty nothingness, and therefore the discovery of "creatures greater than 2cm" megafauna is "surprisingly diverse" ?
If there's any danger, its from the billions of cubic meters under the ocean floor (the source of the nodules, seeping from underneath). More carbon than all the oil we ever burned in our civilization so far.
Is that in any danger of accelerated release? I've not heard of that.
In the long-term, yes, it will eventually reach a steady state. In the long term, though, we'll all be dead.
In the short-term, on timescales that human beings care about, no, we can release too much of it too quickly, before the system reaches a steady equilibrium. Methane has an atmospheric half-life measured in decades, so getting too much of it, too fast, can significantly spike temperatures.
> For the second year in a row, his team have found crater-like pockmarks in the shallower parts of the Laptev Sea and East Siberian Sea that are discharging bubble jets of methane, which is reaching the sea surface at levels tens to hundreds of times higher than normal.
https://www.theguardian.com/science/2020/oct/27/sleeping-gia...