271–280 of 290 posts
IIRC water in earth's mantle is magnitudes greater than the volume contained in our oceans. I think only part of Earth's H2O story is illustrated by this graphic.
The USGS visualisation is based on a 1993 work, discovery of mantle water is later (roughly 2017).
IIR, the Earth's mantle is understood to contain several times the total water content of the oceans, glaciers, lakes, etc. Obviously that water would be somewhat less accessible and quantifiable, but... Anyone familiar with the current geoscience on this?
Earlier quoted context omitted.
> The water discovered in the mantle is not in a form familiar to us – it is not liquid, ice, or vapor. Instead, it is trapped inside the molecular structure of the minerals in the mantle rock. IMHO this is not a productive comparison. Hydrogen and oxygen ions inside minerals in rock is far too much of a stretch of imagination to call as water. https://www.earth.com/news/ringwoodite-mineral-confirms-vast...
> Hydrogen and oxygen ions inside minerals in rock is far too much of a stretch of imagination to call as water. Agreed and to follow that thread to the end: We can't impact that water in a meaningful way. We can't pollute it in dozens of ecosystem-altering ways. We can't alter it's ability to host systems that sustain life. We can't bulk-melt the frozen part & in turn alter the salinity + elevation of a liquid part.…
Earlier quoted context omitted.
The article has a strong focus on "available to humans" and "that humans depend on". Many of the water beneath the crust is exactly that, pumping it up is an important source of drinking water. (In my country, the Netherlands, it's the primary, almost only, source of drinking water)
An interesting point, perhaps it's just me, but my initial reaction to this was that, for purposes of comparison, the volume of "usable" or maybe inhabitable land be measured instead, as opposed to the volume of the entire planet including mantle, core, etc. this graphic seems very prone to misinterpretation and usage as a memetic weapon against globalization, as it is.
I long assumed that the Earth is a "water planet" because water is mostly what you see from a distance. It wasn't until I did the math that I realized that is really about wet rocks in space vs dry rocks in space. Earth isn't made of water, it's just a damp rock. Or a bowling ball that you squirted a dozen times with a spray bottle.
Understandably, since, in this case, surface area is more intuitively captured by our brains than volume.
Also because we are very small. The amount of water, from our perspective, makes it look like a water planet.
Earlier quoted context omitted.
I'm aware, notice my comment specifically states "the Earth's *surface* " not just "the Earth". However, my kitchen counter is a flat surface, it's common knowledge the Earth isn't flat and the average ocean depth is 3,682 meters
The earth is smoother than a billiard ball when accounting for relative size. Highly likely the earth is actually flatter than your countertop when accounting for size.
Earlier quoted context omitted.
No it comes out of the tap as water.
No tap water comes from the mantle.
I think it’s important to keep in mind that if you did this same visualization on a planet with ten times Earth’s radius, but the same ocean depth and water distribution, then the water blobs would seem even smaller in comparison to the planet. I’m just not sure it’s a particularly useful illustration to compare the volume of water on a planet to that of the planet itself.
Earlier quoted context omitted.
We can go a step further with the pedantry, and say that the commenter above is using an unreasonably narrow definition of the work "exponential" and that there are others which allow x^2 to be described as "exponential". https://www.merriam-webster.com/dictionary/exponential
We could, but I would describe it as "mathematically accurate". Which is not incompatible with "unreasonably narrow", given that the definition of "exponential" has recently gotten polluted enough that it is now often synonymous with "fast growing". But what's the point of arguing over definitions if we're going to start with a baseline of saying that there is no basis upon which to argue definitions other than recen…
> > there are others which allow x^2 to be described as "exponential".
> Those same definitions allow x1000 to be described as "exponential". (x1000000 would be "more exponential"!)
> If you're describing something as exponential, then either you're just saying "fast growing", or you're trying to describe the type of growth. If you're describing the type of growth, then neither x1000 nor x^2 is exponential. The fact that x^2 has an exponent in it is no more relevant than saying that x1000=x10^3 and x10^3 has an exponent in it.
I don't agree with this. These are categorically different.
In f(x)=x*1000, as x increases, the function's output increases linearly. The slope of the derivative is 0.
In f(x)=x^3, as x increases, the function's output increases more than linearly. The slope of the derivative is positive and linear.
In f(x)=3^x, as x increases, the function's output increases much more than linearly. The slope of the derivative is positive and is itself a function of x.
These are all categorically different, and refer to something different than "fast-growing". "Exponential" in the mathematical sense, means the derivative is a function of x. "Exponential" in the colloquial sense means that the derivative has a positive slope. "Fast growing" just means that the derivative is large, even if it is a constant.
NB: The infographic and articles are based on a 1993 publication. More recent research, from about 2017, suggests that there's about as much water in Earth's mantle as in all the oceans, so we either need another drop roughly the volume of the first, or the second drop should be greatly expanded. See: "There’s as much water in Earth’s mantle as in all the oceans" (2017) https://www.newscientist.com/article/2133963-th…
> The water discovered in the mantle is not in a form familiar to us – it is not liquid, ice, or vapor. Instead, it is trapped inside the molecular structure of the minerals in the mantle rock. IMHO this is not a productive comparison. Hydrogen and oxygen ions inside minerals in rock is far too much of a stretch of imagination to call as water. https://www.earth.com/news/ringwoodite-mineral-confirms-vast...
In a separate, private graphic, I’d show the available water next to the number of 1 GW reactors, the pile of annual uranium mining output to feed those reactors, and annual calendars it would take to assemble all that to extract the water and dispose of the waste in a way that won’t harm our ecosystem further to express, “if you want this water in a form you colloquially understand, the species possibly can’t afford it”. In case some wise ass decides to bring up that mantle water. But that additional detail would even help technically inclined audiences reading the infographic.