Effect of nuclear fallout on glacial ice

Question

I'm working on building a post nuclear war society in a nuclear winter where northern countries have risen to dominance through a combination of being non-primary targets in the nuclear war and having access to mining infrastructure as well as glaciers and ice caps. The idea is that these societies could utilize their mining infrastructure to mine the depth of glaciers or ice flows to get ice untouched by fallout.

Would that actually work?

And if so would this be sustainable into the future, or would total contamination of the ice be inevitable?

Answer 1

It would work, but:

• Large icecaps end up having surface water find their way to bedrock. You would want to mine ice that was under the surface. It would probably be easiest to scrape off the top few feet of a glacier, then harvest the melt water.

• Mountain glaciers have lots of crevasses. They aren't universal through out the mass, but using anything in the top 100 or so feet may be problematic. (below this depth, the crevasses tend to flow shut. And no, I don't know how the water on the top of the greenland icecap flows to bedrock. Erodes faster than ice flows?)

• The water itself is not radioactive, save for very small amounts of tritium from hydrogen capturing two neutrons. Since the radioactivity is associated with particulates, you should be able to make drinkable water with good filtration, and if that failed, by reverse osmosis.

• Most wells that are over a few feet deep are tapping aquifers with long refill times -- years to millenia. The rock that the water passes through will trap a very large fraction of the particles. So your only issue will be nucleotides that are readily soluble in slightly acidic rain water.

• Checking for radioactivity is simple -- if you have the geiger counter or equivalent. Indeed we can detect radioisotopes at levels well below what is practical for chemical analysis.

• Even if radioactivity is an issue, it is a bigger issue than drinking water. Your entire world is dusted with the stuff. The exposure you get walking around is going to be far larger than what you get from drinking water.

• Remember that your food comes from somewhere too.

Answer 2

It will work, but fallout dust will eventually sip into glaciers via cracks. Maybe they can cover them up with something, e.g. spray (dirty) water on top to form an a crust of solid ice.

A few other concerns:

• There aren't that many glaciers in northern hemisphere, and most of them are in Greenland, which does not have that many people to begin with.

• Scandinavian countries do not have that much mining going on (I assume all coal and ore are used up). Their main mineral resource is oil.

• If all open water is badly contaminanted, farmland will be contaminated as well. So even if survivor can get water from the north, they cannot grow food.

• If they grow food in domes or caves or greenhouses, they can just cycle the water that they have, they do not need constant shipments.

Answer 3

Let's ask Professor Search-Engine for a few numbers:

• What is the water footprint of humanity?

  Hoekstra and Mekonnen in 2012 estimated human water usage a decade earlier at about 9,087 Gm^3/y. 15% of that was gray water (let's exclude it) and 92% of that was used for agriculture. Peeling off the gray water, that's about 7.7 trillion cubic meters of water in 2002 for about 6.3 billion folks in 2002, or about 1200 cubic meters per yer per capita. That's 1.2 cubic kilometers of water for one million folks.

• Where is all the fresh water?

  Igor Shiklomanov in 1993 estimated the freshwater bound in "ice caps, glaciers, and permanent snow" at 24 million cubic kilometers, about 1% of the total water on earth and roughly equal to the amount in groundwater.

• What are the largest glaciers?

  The USGS in 1977 calculated that 90% of permanent ice pack was in Antarctica, and 10% was in Greenland. All the other glaciers on Earth combined added up to less than 1%.

• How big are the Scandinavian Glaciers?

  Lunkka in 2014 estimated that Scandinavian glacier ground coverage (different from volume) was about 0.2% of all permanent ice worldwide.

If you accept these numbers, then Scandinavia has roughly 48,000 cubic kilometers of water locked up in ice (perhaps much, much less since mountainous glaciers are much thinner than the Antarctic and Greenland sheets.

If we pretend that the 0.2% is volume (not area), then the Scandinavian glaciers can support 40 billion folks...for one year. Or 40 million for a thousand years. However, this is really the upper range - those numbers from the 1970s and 80s were before quite a bit of melting. And, of course, the 0.2% is area, not volume.

But you have bigger problems: Water locked up in ice is often not close to where it will be consumed (recall 92% for agriculture). The infrastructure and energy required to pipe or ship or truck and store and distribute all that water from, say, Scandinavia to, say, the rich farmland in Poland is enormous! Remember, we use entire kilometer-wide rivers full of water today.

Let's put that "1.2 cubic kilometers of water for one million folks annually" into perspective:

• That's a 100-tank-car train full of water every 10 minutes, day and night, all year long. A four-track main railway running from the mine to the farmland.

• That's 7.5 Trans-Alaska pipelines.

...for each million folks.

Answer 4

It would work, but it's unnecessary

Deep layers in glaciers and ice caps can quite commonly be uncontaminated by surface activity for hundreds of thousands of years, and in a few rare cases they are over a million years old.

Mining into ice is quite easy; keeping the tunnels open is much harder, but not impossible. Because of regelation and the general plasticity of ice close to its freezing point, the ice will tend to gradually flow into the tunnels and close them. This could be prevented with a tunnelling shield. In practice for a material like ice, recovery is likely to be much more efficient with something like solution mining using superheated steam, a technique that completely eliminates the complications and dangers of tunnelling.

However, none of this is necessary unless the nuclear winter has turned the entire world into a (cold) desert. Potable water is not a finite resource; it is the ultimate renewable resource. It is constantly renewed by the water cycle, which purifies water by distillation. After the few days or possibly weeks required to wash fine radioactive dusts out of the upper atmosphere, any rain or snow falling will be potable. All that is necessary is a way to collect it without it getting recontaminated by contact with soil.

On a small scale this can be done with roof collection. Heavy snow makes it easier: the few inches in contact with the ground will be suspect, but the rest is fine.

It will be much more difficult to collect on a large scale, but not impossible. In high run-off impermeable terrain such as granitic mountains, much of the hazardous material will be washed away in the first few heavy melts. Each subsequent melt will still have some, but the level will drop rapidly with every melt and soon you will be able to collect potable water from gushing mountain torrents on a light industrial scale.

A particular advantage here is that, more than almost any other type of contamination, radioisotopes in water are especially easy to detect and measure, so any source that may possibly be clean can be quickly and reliably assessed.

What if there's no precipitation?

Maybe you have the type of nuclear winter where the entire world is ice-covered. It is too cold for any surface moisture to evaporate, and so there will be no precipitation -- no rain, and no snow either. A global ice desert. This is essentially what Sagan et al. proposed with the original nuclear winter hypothesis: that the smoke of ten thousand burning cities and forests would blot out the sun long enough that the surface would cool so far, that runaway albedo causes glaciation.

This theory is not now regarded as at all likely to be true -- a nuclear war will not trigger a "snowball earth." However if it did, finding potable water is the least of your troubles. No plant life will exist anywhere on earth, and when your tinned food runs out, everyone will die. Actually, you will probably freeze to death long before then, because it's going to get really cold: somewhere in the ballpark of -150°F ... at noon at the equator.