Ice core scientists in East Greenland reach bedrock | Hacker News Reader

Ice core scientists in East Greenland reach bedrock

news.ku.dk

This is a very important project. There is a joke in here about "why not wait 2 years for the ice to melt off if you wanted to look at the mud underneath?" But as the article states, "'This will change climate models because it redefines our basic understanding of how ice moves,' explains Dorthe Dahl-Jensen." Much, if not the majority, of climate science is the creation of models (differential equations mostly) that describe the "response to influence" of the big chunks of things that cause the climate on the planet. The better the model, the better able we are to guess what will happen next (which is sorely needed in a system where you cannot control the input variables by declaration).

One of the big unknowns in the model is "where will the clouds show up?" That unknown stems from our understanding of the water capacity of air by temperature, the increase in air temperature leads to the air holding more water, and water is the basis for cloud formation. If the clouds form "low" they increase albedo and create colder temperatures, if they form "high" they act as a semi-mirrored surface and reflect light that has been reflected from the surface back down for another shot at generating heat.

Much of the IPCC's work has been done in MATLAB[1,2] so if you have a reasonably powerful workstation you can play around with various initial conditions and settings yourself to see what might happen in the future.

No matter what the far future holds, the near future holds more violent storms as storms are powered by the temperature differentials of the air, land, and sea.

It is of note (for me, probably not for many others) that we don't have good models for how an ice age starts. There are a few papers that talk about ice ages being a response to warming (hit a tipping point, generate clouds, and get a "nuclear winter" scenario without the nuclear part). But much of the nuclear winter work has been refined and that scenario is generally considered unlikely AFAICT from what people seem to be publishing these days. Turco's work[3] and things that cite it are a good jumping off point if you want to read up on that. It isn't perfect because smoke/soot are not clouds (different albedo numbers, different cooling attributes) but the accumulation and dispersion of atmospheric obstructions is solid stuff.

[1] Some code and information used to generate plots in the IPCC reports -- https://github.com/IPCC-WG1/Chapter-9

[2] Mathworks trying to get you to buy their climate data toolbox -- https://www.mathworks.com/discovery/climate-stress-testing.h...

[3] Climate and Smoke: an Appraisal of Nuclear Winter -- https://www.science.org/doi/abs/10.1126/science.11538069

Wow, thanks for the links, this is really neat

You're adding important context but I would like to clarify something to highlight just how complex climate change really is. I also am going to make a few related comments, as I do most of my research on melt in Greenland. Full disclosure: I do know some of the people in this article but I have never been to eGRIP specifically. I will be in Greenland in a week nearby though.

   No matter what the far future holds, the near future holds more violent storms as storms are powered by the temperature differentials of the air, land, and sea.

This is true, sort of. There's a lot nuance needed for this broad statement. In particular, "Arctic amplification" means that the pole-to-equator temperature gradient is actually weakening. If you were inclined to believe the covid lab leak theory you would also be inclined to jump on this and say "then the extreme storms are nonsense". However, what's really happening is that the waves in the upper atmosphere ("Rossby waves") are getting more wave-y. Which is really saying that additional energy from CO2 warming is resulting in stronger transport and more significant variability. It's not resulting in larger gradients. Although sometimes the gradients are also extreme.

Climate is a question of two things, time scales and spatial scales. Dumping a bunch of CO2 in the atmosphere messes with both.

I also want to point out that this isn't the first time a core has been dug to the bed of the Greenland ice sheet. It's also not the second. Some comments seem to be implying this. I have a bad taste for science reporting/announcements like this that fail to provide context. Of course this is important work but it's following up and improving on several previous deep core drilling experiments. We still have many samples from these previous cores. This is still a very good thing to research and will hopefully provide important new insight. But there is significant previous work it builds on [1]. And the title kind is vague enough that outsiders/the public might not understand that.

Also also, to be a little vitriolic, the IPCC Matlab code is a crime against humanity and fuck Mathworks.

[1]https://www.sciencedaily.com/releases/2021/03/210315165639.h...

Also work on ice, though not with cores. Just 2nd'ing this as being a great point. Arctic amplification is fascinating and IMO understudied relative to its importance.

The distinction I believe the article is trying to make around the "first-core-to-ground" sentiment, is that this is the first time a core has been drilled through the full thickness of an ice *stream*. These are regions of an ice sheet with very rapidly moving ice. Ice loss from ice streams may have a larger and more immediate impact on sea level than other regions in Greenland and Antarctica. However, I do not actually know whether this is the first core drill ed through an ice stream, but I'm assuming that was the article's intent.

I'd add that although the intergrated yearly average pole-to-equator gradient is indeed weakening, in terms of extreme storms this probably doesn't matter since the gradient is still very strong in winter months in the Northern Hemisphere, and if you pump the atmosphere with more water vapor from the tropics, then intense seasonal storms and extreme flooding can be expected for at least half the year in the Northern Hemisphere - and in midlatitudes, the east-west motion of frontal systems complicates the issue further (though it seems increased water vapor is driving that engine more than anything else).

The Artic amplification effect appears to be having a big effect in the summer months as the decreased gradient allows the polar jet stream to meander southwards, resulting in random persistent blocking events (responsible for recent spate of heat waves) related to Arctic amplification effects on the jet stream (in both hemispheres). Good discussion here:

https://www.carbonbrief.org/jet-stream-is-climate-change-cau...

> IPCC Matlab code is a crime against humanity and fuck Mathworks.

High five and +1.

> If you were inclined to believe the covid lab leak theory you would also be inclined to jump on this and say "then the extreme storms are nonsense".

What does the "COVID lab leak theory" and the "belief" in it have to do with this? conflating these two does only one thing, it further polarises and politicises the already heavily polarised and politicised debate around (anthropogenic) "climate change". It is already nearly impossible to have an objective discussion on this subject without conflating it with other similarly polarised subjects so adding this trip wire does not improve things, at all.

A lot of modeling is moving toward Julia, so if you don't want to give money to Mathworks here are some alternatives: https://juliaclimate.github.io/Notebooks/

I have moved all my "matlab like" work (mostly signal processing) into Octave for that same reason.

GNU Octave is surprisingly good. I had old MATLAB work from university that I wanted to revisit for teaching purposes, and was surprised by the lockout imposed by the pricing model of MathWorks[1] (120 € for an individual license, 260 € for teaching)

1: https://nl.mathworks.com/pricing-licensing.html?prodcode=ML&...

Note that the individual license for Matlab is $149/year [0], which isn't crazy IMHO.

0 - https://www.mathworks.com/pricing-licensing.html?prodcode=ML...

Agreed, it's sofa change for an institution. But I remember cost being a big obstacle when I first wanted to learn serious programming around 1990, so I feel like free programming languages are better.

The institutional cost is more AFAIK, but should still be pocket change -- one productive week pays for it. But the price is just high enough to trigger all sorts of weird management wastes. Especially if you envision wanting more than one installation, or are in an austerity-culture organization.

While you're dealing with the time and aggravation of budget approval and recurring license management, I've got my Python and Arduino toolchains installed on literally every computer that I touch: At home, my office, the labs, etc.

Given the added burdens of...

- managing licenses across multiple devices

- limiting the people you can share code with to ones that are willing to deal with licenses

- budgeting for an ongoing subscription / renewing as needed

...I'd say that even $10/year is too much. Ecosystems that create collaboration barriers like these are no place for important work.

The support and documentation for MATLAB is really unparalleled though. Worth every penny when you want to focus your time on being productive, rather than banging your head against the language.

That sounds like a welcome change from the 2000s where we had to hound them for even obvious flaws.

Different worlds I suppose, but for me it doesn't count as "productive" unless my audience is successful. So having support for myself doesn't get me very far.

Without any toolboxes though, and you'd typically need a handful of those depending on what field you're working in and that's another $45 per toolbox. But also anyone just getting started may not know which toolboxes they need upfront which increases the uncertainty about the price.

I really wish they had a more reasonably priced all you can eat home license that included all toolboxes.

Sure, if you work alone, don't collaborate, and don't require any extra toolboxes.

I've seen various communities move from Matlab to Python, Octave, R, and Julia notebooks (that now support several languages). Ease of collaboration (including git repos and notebook interfaces), transparency of the platform (to tell what it's really doing), and ability to use computational resources.

I had a request from a grad student to run a simulation on a 40 node cluster. Said cluster cost $110k, including 40 nodes costing a bit over $2k each and some networking/storage. This would have reduced their embarrassingly parallel projects for their phd from 6-12 months to 5 to 9 days. Sadly the required matlab licenses would have cost more than $110k (the cost of teh hardware) because of the licenses and extra toolboxes. They cried. They had to delay their graduation and either reduce it's scope or rewrite it.

As a "cloud person", I just want to add a few things to the description of how clouds affect the climate (and why high clouds have a wamring effect).

All clouds are white, so they all reflect sunlight back into space (during the day), cooling the Earth.

All clouds are (almost) black in the infra-red, meaning the amount of energy they emit in the infra-red is determined by their temperature. Colder clouds emit less energy.

Almost all clouds are colder than the surface beneath them, which means they emit less infra-red energy to space than a clear day would. This reduces the amount of energy the Earth emits to space, so warming the climate.

High clouds are colder than low clouds, so have a stronger warming effect.

In summary:

Low clouds - Reflect sunlight (cooling), don't trap much infra-red (little warming)- Net: Cooling effect

High clouds - Reflect sunlight (cooling), trap lots of infra-red (stronger warming) - Net: Warming effect

I wish I were a cloud person.

When I read that first sentence, I thought “what has cloud (software) to do with this”

Not series, maybe a bit serious:

Cloud computing energy use appears to be on an exponential trend driven by general trends (all things automated), with new forms of automation compounding competitive pressures (deep learning models quickly getting larger, more powerful, more useful, and more versatile in a way erasing many lines holding back past competition.)

At some point, it seems inevitable that computing usage will be a first level climate driver, regardless of how green the energy is.

Harnessing orbital solar, fission and fusion power, may solve the CO2 energy problem, without requiring us to steal the biosphere's energy needs, but will eventually create a massive waste heat energy problem.

Unless we find someway to efficiently transfer mass amounts of heat energy off of Earth.

Or we eventually limit computing on Earth, and export that to the Moon and beyond.

I’m so ready to deploy to the EARTH-LUNAR-1 region and backup to JUP-EUROPA-1.

How significant a climate change factor is waste heat energy across all sources currently?

I once was told I was using the word clustering wrong (I was doing k-means, not computers).

This thread likely reads very interestingly for those with the "Cloud to Butt" [1] chrome plugin

[1] https://chrome.google.com/webstore/detail/cloud-to-butt-plus...

I didn’t install the plug-in, but made a mental substitution and reread the thread. Now I am chuckling like a grade schooler over some madlibs and dribbled coffee down my shirt.

Maybe I should describe my job differently...

That's interesting. How relevant is energy transport in comparison to the optical effects?

Eg: my understanding is that hurricanes are net cooling because they transport heat from the ocean surface to the upper atmosphere. Presumably the same can be said for cumulonimbus/thunderheads? Or perhaps it is more relevant when they form in the day and when they dissipate at night?

This is related to my reply above, but clouds in general move heat upwards in the atmosphere through latent heating.

When you evaporate water from the surface, you cool it (like sweating keeps you cool). This water vapour is then lifted by convection until it cools enough to condense and form a cloud. As the water vapour condenses, the opposite happens and it heats the atmosphere locally (this further invigorates the convection)

Once you have condensed enough water (and the water droplets/crystals are large enough), you form precipitation. This falls back to the surface (some evaporates along the way), where the process starts again.

This transporting of energy through the water cycle is an important component of how energy moves in the Earth system - you can see it on this figure as 'latent heating', moving energy away from the surface at something like 80Wm^-2

https://www.globalchange.gov/browse/multimedia/earth%E2%80%9...

This IR satellite view of clouds and water vapor centered over N/S America is pretty nice. You can also see the daily pulse of cloud formation over the Amazon rainforest:

https://youtu.be/f7QttjGu628?t=142

I will give you the benefit of doubt given it's Hacker News you likely are an expert, but this feels like one of those "sounds too intuitive to be that simple" type complex factors. Any literature on the topic from which I can improve my understand?

What part of it do you doubt? It’s obvious that clouds are white, and it’s obvious that they are cooler than the earth and even colder higher up (clouds form because the adiabatic expansion of rising air cools it down and causes water to condense, and the higher up you go the colder the atmosphere due to greater expansion - anybody who has hiked the mountains has experienced this).

The only assertion here that one has to take on faith is that clouds are approximate black bodies at infrared wavelengths (which isn’t surprising - most things tend to be), and the relative magnitude of the cooling vs warming effects. Oh and there is an unstated dependency that the Earth is also an approximate black body at infrared wavelengths.

Granting that the two effects counteract each other, it is surprising that the crossover point would happen within the range of variation of actual clouds on Earth. My uninformed guess would have been that nearly all clouds' effects are dominated by only one of the two effects—probably, by the cooling effect.

I think the concept of the albedo of the poles is another simple idea that explains why melting poles would be bad and accelerate global warming further, because by being white they reflect back sunlight for a huge area. Kinda intuitive if you have ever touched the black (opposite color) coolers on a desktop computer and felt your hand fry

Not all water vapor is clouds. Where relative humidity is too low it comes with all the warming but none of the cooling effect. A tiny change in humidity (cloud/no cloud) can change things significantly.

I have a question for a cloud person, maybe you can answer it.

When it rains, where does the latent heat go? The latent heat of evaporation (or condensation) is absolutely huge. Condensation means heat is released. I did a back of the envelope calculation. 2 mm daily rainfall x 500 million km2 = 10^15 kg; each kg of water holds 2.26 MJ of latent heat, and there are 86400 seconds in a day, so that's 26.15 W, so overall 26150 TW. The Earth receives about 173000 TW from the Sun, so this is about 15% of the energy received from the Sun. Obviously, not all the 15% goes out to space, but about how much does go to space?

It heats up the atmosphere and eventually gets emitted back into space!

For the Earth's temperature to remain approximately constant, the energy leaving the system (as infra-red) has to balance the energy entering the system (as sunlight).

The atmosphere is almost transparent to visible light, so sunlight doesn't really heat the atmosphere at all, it mostly heats the surface.

In contrast, the atmosphere is mostly opaque to infra-red (apart from the 'window region' at about 10um), which means energy is mostly emitted from higher levels in the atmosphere.

This means that you have to have a way of getting energy from the surface (were it effectively 'arrives') to higher levels in the atmosphere (where it can leave the Earth system again. Latent heat is an important way for this to happen - you can see it in this figure, showing how energy flows in the Earth system

https://www.globalchange.gov/browse/multimedia/earth%E2%80%9...

It would seem to me, that the best way to do long-scale climate models of a body ; knowing its composition in layers over time is really important to be able to calculate the flow of the layers of composition as particles.

Think of the experiment of light as wave/particle...

Glacial/geological scales operate as thus ; as physical masses of particles, but move in more wave-like manners - so you'll have material suspended and located in the overall mass based on how they were consumed as a particle, but the characterists of the glacial mass will appear to be acting like fluid waves.

So maybe if you know the timeline of a glacial flow, you can predict where the most particulate-glacial-slurry is held (thus minerals, biologic wash off in certain events etc.

Perhaps? Not sure I'm following the methodology you're suggesting. Most (perhaps all?) of the climate models I've read about or played with are based on energy balance. (energy in vs energy out)

Start with Solar insolation (energy in) then subtract all the ways that energy leaves the planet (reflection and radiatively from the atmosphere.) Then add that the planet is its own heat source (molten core and all that) and that energy contribution. Then add variable convection to the atmosphere based on latitude. The list goes on and on (which is kind of like harmonics in a Fourier series).

Then random things pop out like how reducing the weight of ice (by melting) increases volcanic activity kinds of things.

Based on the criticisms I’ve seen, the melting ice / volcanism theory isn’t true.

That result didn’t pop out of existing climate models, it was an effect they explicitly made a domain specific model to look for.

This is how most climate models are made - bespoke models for a small application using other global models as boundary conditions.

https://ui.adsabs.harvard.edu/abs/2009AGUFM.G53B0673L/abstra...

Excellent link, added it to my papers collection!

This is off the top of my head ;;

We could use a reverse-mycelium method of acruateley mapping actual climate change, as opposed to NRO satellites with filter information.

Create a sensor (this is the reverse mycelium part) - which is effectively the FRUIT of the mycelium plant - the Mushroom.

These sensors havea range of features, but they measure aspests of soils, light, air quality, etc...

And they look like solar garden lights - but they then talk back to a system whereby they all compare notes - the Mycelium - and adjust and then are read to predict the patterns based on inputs from the other sensors of windflow with particulate...

YES this is what the NRO and the NROAA(?) [people that look from space] do - but here you just start deploying such systems such as PURPLE air monitors do...

Or adding features to those...

I think we can have a much more fine-tuned climate model if the air sensors were made larger, deeper penetrating into the earth and be able to correlate a bunch more standard measurements we typically take for a specific are (Ph, moisture, elements that can be detected, rainfall, etc - we need "smart land bouys"

>>reducing the weight of ice (by melting) increases volcanic activity kinds of things

Thank you! I was literally just thinking about how hydro-geologics(?) have an impact on the earth - e.g ;;

Do lunar tidal forces affect frozen water differently than liquid water, salt water, fresh water - if the waters have a homogenoius gravitational density for each state - then the state of these will affect lunar pulls? given each's volumes geo distributed around the globe? (the solutions affect the volume - so does a cubic meter of saline, vs sea, vs, bottled, vs spring waters have a different gravitational mass - so the distribution of the various states in global scale qty may have some impact on earths (spin?Wobble?Tides?Climate?)

/sci-fi - thanks for letting me think that out loud.

Thus as the climate changes, the wobble changes, thus the prescession, etc...

I wonder if you were to suspend spheres of water in different solutiuons or states inside the giant antarctic neutrino detector - with sensors for each sphere, if you would have different readings of the neutrino interactions...

So basically an array of neutrino-reflectors - such that if you detect a neutrino into the ice array - then it goes through another material sphere (whichever medium your choice is) and then the output from there....

That would be interesting to see how to affect neutrino behavior on a materials basis... and if you can LLM the heck out of all data - you get the idea...

So if you can aside from detecting neutrinos - you have hover materials with aversion or fondness...

point is that one may be able to take ingress, inflection/reflection (through material substance types) and learn how to reflect and steer neutrinos - unless they 100% peice their normal regardless of any input.?)

(can they be captured?

I came up with an hypothosis ; particles amd waves work orthoganly -

The particles will have the energy in direction A <-- They only flow in direction, but have zero control

But a wave is the ability to PUSH

So if its a recipricating PULSE, it has the wave of PUSH - this velocity can be proximity - (RSSI) type...

so aside from lidar (which I have spoke on) - you reflect the UVs (i met an PHD on this and he revealed) --- so LOAA is scanning material types - and thus is in the position to TARGET material,,,

This is super secret

I would like to ask in general to the group. How do I get a job doing field work? Like working on sensors but then also going outside and working and doing analysis?

Become a grad student or post doc? Alternatively you could get a doctorate in the science of your choice and then join and agency that is using that science in its mission.

Interesting: "Towards the base, the ice is more than 120,000 years old and dates back to the last interglacial period, a time when the atmospheric temperature above Greenland was 5°C warmer than today."

I'm not a scientist so I'm curious why this is interesting.

Presumably because we can find well preserved organisms from that time.

It's not scientifically interesting, the glacial-interglacial cycles are pretty well established. I'm guessing they're trying to insinuate some climate change minimalism argument.

It’s interesting to know how far back in time the ice will allow them to analyze once they get to the base.

I think people who are not already familiar with the known history of the Earth find it interesting that there have been higher CO2 levels and temps than there are now.

And I agree: the history of the Earth is interesting. Which is why so many people study and work in the field of geology.

the drilling allows sampling of environmental components over extended period of time. this meas a historic record of, gases, ash, soot, pollen, spores, silt, insects, plant animals, metals, salts.....

It's interesting because the whole ice cap as we know it is around 120k years ago which I don't consider the long ago on human development scale. This also appears to mean that in the past 120K there wasn't a polar ice cap. I read that as the worst case scenario we should be using for long term planning. This also may help determine how fast the ice was built and how fast it will melt.

I'm completely an armchair ponderer.

This will also assuredly fuel some interesting ideas about the origin of the Piri Reis map. A 120k year old ice sheet could mean that humans once lived on Antarctica.

It does make one wonder if any ancient sea fearing humans happened to carve a world map into a durable material such as granite which could have survived until the modern historic era. Maybe such a map, or other mythological artifact fueld the Roman idea of Terra Australis Incognita

/End rampant unsupported armchair speculation

https://en.wikipedia.org/wiki/Piri_Reis_map

https://en.wikipedia.org/wiki/Terra_Australis

The Polynesians used stick maps to identify currents and land masses relative positions.

With no evidence I believe navigation cues were built into the vessel. By keeping celestial bodies aligned with marks on the vessel one can achieve a seasonal calendar as well as documentation on how to modify the configuration for the next leg of the journey.

IIRC the 'maps' made of organic materials were very much a rarity slash teaching aid for the later incarnations of traditional navigation cultures of the Pacific which we have surviving material on. Mostly they used mental maps, and of course the most sensitive instruments available at the time ... at least one example of which was hanging their balls off the edge of the canoe to see if they could detect a temperature shift. A good book on the subject is We: The Navigators though it draws only from one area.

Source: Have a Pacific art collection, have been to most of the major museums on the subject, interested in sailing, authored some of the Wikipedia (featured) articles on related watercraft.

Yes, I would believe that some as fragile as the stick maps was no way to cross an ocean.

What I think is interesting is the physical representation of an oral tradition. This is different than writing as employed today.

Yep. All art is interesting for its relative flattening of multi-dimensional realities in to lesser-dimensional representations. Key concerns for the navigators were signals such as migration patterns, seaweed and other flotsam drift currents, temperatures of said currents, star positions, wave qualities, dominant wind directions, conditions and precipitation and cloud over seasons. These dynamic realities cannot be flattened in to any standard two dimensional representations even today, yet often emanate from or are disturbed by the often-tiny landmasses they would specify as origin, destination or reference points within the navigation problem. In the same way modern navigation uses multi-layered systems like bathymetric maps, local depth sensors, RADAR, GPS and navigation lights to provide orientation and safe passage amongst static and dynamic obstacles, so too the traditional navigators combined layers of sensory input considered too subtle for modern systems yet potentially equally effective in their place and season.

Probably the migratory patterns were as import at as any other reason to travel.

What I seem to be noticing is that the ancients used calculus all the time but it was the geometric tools that they used.

This gave technology a form.

Arabic numerals made tabular data more useful leading to the more number based tools.

This seems to have removed the form from technology.

Even without an ice sheet, would antarctica be hospitable? It'd still be cold and a desert I imagine, in darkness through the winter, etc.

Maybe humans become more developed because it got colder? Even on a country and global scale, the south is usually "behind" the north. It's hot, no one wants to do anything.

The American south (Arizona, Florida) were tiny and unimportant until air conditioning entered the chat. Phoenix was at 100 thousand people in the fifties.

The cold makes us think, the cold make us survive, keeps us on the edge - where we need to be. Respek the cold!

This is pretty ahistorical. Most of the world's great civilizations have been from warmer climates. Northern Europe is an exception, not the norm.

All of the world's "great" civilizations come from places with strong seasonality. The ones that didn't have winters had flooding seasons and dry seasons. Some of them had both. It also doesn't need to be bitterly cold for winter to have an effect on crops.

Sumeria and Egypt both had seasonal flooding. Italy and Greece have winters that are cold enough to disrupt agriculture. The Aztecs and Mayans had seasonal floods. The ancient Chinese empires had both. Japan has winters. The list goes on.

On the other hand there’s something to be said for a comfortable climate that leaves people with time to think when the everyday isn’t a constant complex struggle.

The Inuits of Greenland and Sami people of Lapland didn’t have Aristotle or Confucius.

That is only due to writing. I always felt that the high latitude civilizations led to technological development due to the high risk and high solitude.

Maybe there's a "sweet spot". Too warm and not enough seasonality leads cultures to not be that productive, but too cold and daily life is just too much of a struggle to invent calculus. Greenland and Lapland are probably too far north to have decent agriculture, and never had large enough populations to develop much civilization. Cultures that had people like Aristotle or Confucius had very large populations for the time.

That we know of; did they have a system of writing?

I find it hard to believe they wouldn't philosophise at all. Confucius got famous (like sun tzu et al) because his ideas were written down, published and spread.

The number of different words they have for snow and ice demonstrates a cultural understand of distinct attributes of objects. I think this would be the first step of consciousness understand one thing as distinct and separate from another.

I find it interesting because it raises questions that I don't have answers to. For example:

- What caused the temperature above Greenland to be 5°C warmer than today? Why is it cooler now compared to 120,000 years ago? What causes the interglacial periods? Is glaciation the more common state of the climate?

- The article says the ice sheet is melting at the bottom? Why? Pressure from above? Friction from movement? Heat from the Earth? Something else?

- Was the ice sheet shrinking or growing when the temperatures above Greenland were 5°C warmer than now? Does existence of the ice sheet imply that 5°C warmer for some period of time is not enough to melt the Greenland ice sheet?

- How much climate data has been lost to melting from the bottom? Is the ice sheet thickening or thinning compared 120,000 years ago? How would we know?

- How much has the Greenland land mass moved in 120,000 years due to plate tectonics? Could this have impacted the ice sheet in this short amount of time?

- Humans adapt. How did humans adapt to a climate that was warmer by up to 5°C 120,000 years ago?

- How long did the warm temperatures persist 120,000 years ago? 10,000 years? 50,000 years? Or more?

- Could a cooling climate be more worrisome to humanity than a warming one?

120k years ago in context:

  * 170,000 years ago: humans are wearing clothing by this date.
  * 125,000 years ago: the peak of the Eemian interglacial period.
  * ~120,000 years ago: possibly the earliest evidence of use of symbols etched onto bone
  * 75,000 years ago: Toba Volcano supereruption that may have contributed to human populations being lowered to about 15,000 people

https://en.wikipedia.org/wiki/Timeline_of_prehistory

The Eemian climate is believed to have been warmer than the current Holocene. Changes in the Earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as Milankovitch cycles, probably led to greater seasonal temperature variations in the Northern Hemisphere. During the northern summer, temperatures in the Arctic region were about 2-4 °C higher than in 2011.

The hippopotamus was distributed as far north as the rivers Rhine and Thames. . . . The prairie-forest boundary in the Great Plains of the United States lay further west near Lubbock, Texas, whereas the current boundary is near Dallas. . . . Sea level at peak was probably 6 to 9 metres (20 to 30 feet) higher than today . . . .

https://en.wikipedia.org/wiki/Eemian

This raises a very critical point. Nuclear is the only dependable energy source. Fossil fuels will run out or go out of favor. Solar and wind on the other hand will become victims of the next major volcanic eruption as ash destroys them or renders them ineffective.

Deep drilling based geothermal can fill this role too though - and does have the substantial benefit over nuclear that it leaves no surface-supply chains for resources (uranium).

Given that we're so close to being able to do it, we honestly need a Manhattan project initiative to push it through to reality (with the outcome being the machine and process to do the drilling).

Nuclear facilities seem pretty fragile / demanding, I doubt one would survive any kind of apocalyptic event. The infrastructure supporting it will be gone.

isnt that the case with any advanced technology? (including wind and solar)

Yes.

Though as a corollary, such an event would be civilisation-ending in any regard.

It's also ... highly rare. Somewhere in the 1 in a million to 100 million year range, which is to say, not only longer than the planning horizon of most human institutions, but well outside the existence of the human species for the most part.

It's also well beyond the available supply of terrestrially-minable uranium,[1] and possibly of ocean-extracted uranium,[2] and thorium[3]. Breeders might be another option, though I've seen no substantive estimates of total fuel availability for that case either.[4]

But as an argument favouring nuclear over other energy options ... this is pretty silly, really.

About the only viable defence against such a risk would be, and I say this as someone who's markedly pessimistic on space colonisation, independent and self-sufficient habitations off-Earth: YACP.[5]

________________________________

Notes:

1. If we relied on naturally-occurring terrestrially-mined uranium for all present human energy consumption ... supplies would last fewer than two decades. This is seldom mentioned by nuclear advocates.

2. This offers a potentially much larger supply, as uranium is present as a solute in seawater, but viable industrial-scale extraction is unproven and would require filtering vast quantities of seawater.

3. Thorium is reasonably abundant, though I'm not quite sure how abundant. Thorium-based reactors are not much used, and the concept of molten-salt reactors (MSR) which gained some popularity in the past decade ... faces some very significant engineering hurdles. Managing high-temperature highly-corrosive radioactive salts is ... challenging.

4. Breeders produce plutonium. And now you have two, or more, problems.

5. Yet Another Challenging Proposition.

Nuclear facilities can probably continue to operate amid persistent cloud cover and ash. Wind turbines and solar can not. Agriculture would have to shift artificially lit greenhouses.

An eruption significant enough to impact solar and wind generation globally will also affect other critical requirements of humanity, and the Earth's ecosystem, globally.

Which is to say: You Will Be Having Bigger Problems.

Recovery from regional meterological catastrophes is well within human capabilities.

Bigger problems than no power in the worst year imaginable. Give me a break.

Yes, no agriculture is an even bigger problem than no power.

You don't think modern agriculture and energy are intimately related?

I'm honestly a bit shocked.

I do think they are, but it's also (obviously) the case that if an eruption blotted out the sun and disrupted wind currents, having the ability to keep generating power would not help much because the plants and animals we eat would all die.

And what's with the weird tone? It's a super banal point that our food requires sun. I highly doubt you're "shocked" by it.

Yeah. Crop failures and famine. Way bigger problem.

And depending on the eruption, for anywhere from years to centuries or longer.

Availability of energy can mitigate crop failure and lack of energy also leads to crop failure.

How can people not generally understand the connection?

You are thinking too far ahead. There is a real risk of persistent cloud cover and ash in many places without total crop failure.

There is definite evidence of hominins in North America 130,000 years ago (search "Cerutti mastodon"). Nobody knows if they were H. erectus, Neanderthal, Denisovan, modern humans, or "other", but with an interglacial at 125,000 years ago, it is not hard to see how they could have got here.

Wikipedia suggests this is not definitive, and maybe not even evidence:

https://en.wikipedia.org/wiki/Cerutti_Mastodon_site#Criticis...

This article is much more sympathetic (and also a fun read):

https://www.latimes.com/local/california/la-me-cerutti-masto...

I’m no expert but it seems like this is still a controversial idea.

Wikipedia over-represents the opinions of retired professors. As Max Planck wrote, "Science advances one funeral at a time".

The usual shallow, reflexive objection is that the bones must have been broken and carefully re-arranged via being run over by construction equipment. This absurd suggestion has been very thoroughly demolished without assistance from construction equipment. It is hard for dump truck tires to produce green-stick fractures in 130,000-year-old bone, or to put bone fragments into the pores of stones and then move them yards away, all while underground.

"75,000 years ago: Toba Volcano supereruption that may have contributed to human populations being lowered to about 15,000 people."

The key question is: How much CO2 did that super-eruption emit into the atmosphere?

In our hurry to attribute climate change to our meager impact on this planet, we tend to forget what horrors an eruption of this magnitude can cause. And who knows how many of them happened during the past millennia.

> And who knows how many of them happened during the past millennia.

We at least have a significantly large list of what we know [1] - that's part of the purpose of core drilling, the ash deposits worldwide can be linked together to estimate where ash traveled to. Also, craters and their surrounding can be drilled into to determine eruption events.

[1] https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptio...

Here's a study:

The size and frequency of the largest explosive eruptions on Earth, Mason 2004

https://www.researchgate.net/publication/227000709_The_size_...

Volcanoes aren't about the CO2, they're about the ash which blocks out the sun and makes it colder.

The figure I've found is 2800 km^3 of approximately granite, which at 2.7 tonnes per cubic meter gives about a billion gigatons ejecta.

I've never found a CO2 estimate, but did find that it's a significant amount of that mass, as is SO2.

It wasn't worth me doing more of a sketch since it's not clear how to model the effects of such a massive system.

I was struck tho, that the magnitude of this and a few other events in the not too distant past, are vastly larger than even all put nuclear war

It's not clear to me that our CO2 emissions are very significant in comparison

Wikipedia cites a range of 2,000 -- 13,000 km^3.

<https://en.wikipedia.org/wiki/List_of_largest_volcanic_erupt...>

As for the gaseous component of ejecta:

Water vapour is consistently the most abundant volcanic gas, normally comprising more than 60% of total emissions. Carbon dioxide typically accounts for 10 to 40% of emissions.

<https://en.wikipedia.org/wiki/Volcanic_gas>

Citing: H. Sigurdsson et al. (2000) Encyclopedia of Volcanoes, San Diego, Academic Press.

(Late edit: though I note that this seems to discuss percentages of gaseous emissions, not total ejecta. Anyone have a better source here?)

One of the largest volcanic events I'm aware of is the Siberian Traps eruption, about 250 mya, with a volume of about 4 million km^3, another three orders of magnitude greater than Tomba.

This has been linked to the Permian–Triassic mass extinction event, with the mechanism being release of methane clathrates and/or stimulating growth of a microbe which released vast quantities of methane into the atmosphere, killing ~81% of all extant marine species and 70% of terrestrial vertebrate species.

<https://en.wikipedia.org/wiki/Siberian_Traps>

"The level of atmospheric carbon dioxide rose from around 400 ppm to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period."

-- Wikipedia, citing Wu, Yuyang; Chu, Daoliang; Tong, Jinnan; Song, Haijun; Dal Corso, Jacopo; Wignall, Paul B.; Song, Huyue; Du, Yong; Cui, Ying (9 April 2021). "Six-fold increase of atmospheric pCO2 during the Permian–Triassic mass extinction". Nature Communications. 12 (1): 2137. Bibcode:2021NatCo..12.2137W. doi:10.1038/s41467-021-22298-7.

<https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extin...>

Good finds. Thanks!

Yeah, it's the comparison between DRE and Gas ejecta that got me bogged down before.

Having now given up, I asked ChatG4. It says "the mass ratio between DRE and gaseous emissions might be on the order of 20:1 to 100:1", no citations ofc.

So, just as a strawman and using your 10-40%, on the low end .01.1 = 0.001, high end .05.4 = 0.02. So .1%-2% of ejecta by mass is CO2 emissions. Hah :)

Using my orig figure for Toba of a billion gigatons of ejecta, of which roughly a million gigatons would be CO2. Correct math?

Human GHG emissions are ~50 Gt/year.

DRE == dense rock equivalent:

<https://en.wikipedia.org/wiki/Dense-rock_equivalent>

Math glitch. It was a million gigatons DRE, so 1000 Gt CO2

I think people struggle with the magnitude.

Mt St Helens, for example. Not the largest eruption.

But a landslide of approximately 2.5km^3 (over 3 billion cubic yards).

Okay, some say, so that is a lot of earth...

and then you learn that the landslide was moving at speeds of up to 160mph.

That's a LOT of energy.

It sure is. And we've yet to survive our modern-day supervulcano eruption.

"And who knows how many of them happened during the past millennia.

Geologists. And the answer is "none" for the past 25 or so millenia, and "one" since Toba.

Also, unless you've had supervolcanoes go off in your bedroom and didn't tell anybody, the evidence for human impact is exceedingly clear.

"Geologists."

Geologists might know, same as astronomers might know what Black Holes and Pulsars really are.

On the other hand, it is a geologist's call to search for answers and for truth. Saying that they truly know is the same as saying nothing.

Not even close to what we as humans emit. The rate of the global annual natural CO2 emissions are 1-2 orders of magnitude slower than anthropogenic emissions.

If you're trying to minimize human caused warming with the rare eruption of super volcanoes, it's pretty weak.

Where is the evidence of human effect on the climate change? There is a huge effect on pollution, but hardly any on the global climate.

Considering the rapid rise in temperature on a relatively miniscule geological timescale, I'd be more interested to see evidence that it's not a manmade phenomenon.

There's a huge increase of human population living in very large cities, when compared to 100 years ago. Especially in China and India.

Of course the people will feel the local rise of temperature in asphalt-ridden and industry-polluted streets. It's logical.

This does not mean that global climate has changed.

Iirc, the CO2 concentration now as been pumped up higher than it was then, which is in part what is worrying because temps might then potentially shoot even higher.

Bottom line: we need large scale carbon capture quickly because even if we reach net zero CO2 will take millenia to drop back to the level it was pre-industrial revolution.

Edit: I wouldn't focus on "pre-industrial levels" specifically, the point is that there is too much now so we most likely want concentration to drop as soon as possible.

Why do we need to get back to the levels pre-industrial revolution?

The point is that net zero is most likely not going to stop warming with 400+ppm CO2 in the atmosphere. CO2 concentration most likely has to drop but naturally it does so very slowly. Arguably at this point we already need cooling because 40+C every summer in half of Europe (for instance) is getting annoying...

> at this point we already need cooling

A colossal volcanic eruption could do the trick, and those seem to happen rather unnervingly frequently.

Yeah it would be pretty silly for humanity to invest so much time and effort into lowering CO2 levels only for a Yellowstone or equivalent to erupt and send temperatures plummeting into a new ice age levels. When if humanity did nothing the eruption would only have taken us back to pre-industrial age temperatures.

Pre-industrial CO2 concentration is synonymous with the "natural concentration", at least in the recent past. We made a very large change that has thrown Earth's systems out of equilibrium. Returning to pre-industrial CO2 levels would undo that change and bring things back towards equilibrium.

They are dynamical systems, there is no equilibrium. See also: climate charts for the last few ice age cycles.[1] In the bigger picture we want to modify Earth's climate and definitely do not want to end the current interglacial period, to be fair we've already done that, but returning to a "natural" pre-human climate cycle on the 10,000 year scale is not desirable.

1. https://energyeducation.ca/wiki/images/8/8f/Ice_ages2.gif

Dynamical systems can have equilibrium points —- e.g. an inverted pendulum is stable when hanging straight down. If you deviate too far from an equilibrium point, the system may find another equilibrium that is less desirable for the user. I’m not an expert in climate change, but those things certainly happen for engines, robots, and other systems.

Like the other reply said, there is no natural equilibrium.

We want to return to pre-industrial levels because we’re used to it and we liked it more then.

Really

I like to think of it as scrappy terraforming because we aren't even sure we could handle any of the naturally occurring variation.

Scrappy because, well the planet doesn't quite become uninhabitable and we're starting from the end-game. Science fiction also had me expecting some very cool terraforming infrastructure, not psy-ops to get the serfs to eat bugs.

“Natural concentration” is not the right way to look at it because there are higher concentrations that predate the industrial revolution and humans. The all time high (that we know of) is from about 350,000 years ago. This was by all means natural and pre industrial revolution.

"The only known natural concentration empirically compatible with long-term human civilisation".

"The planet did exist/will exist just fine without us" is a pretty worn truism. You might as well wryly note that water isn't natural because everything was hydrogen once.

> empirically compatible with long-term human civilisation

Empirically observed, atmospheric CO2 went from ~320ppm to ~410ppm from 1970 to 2020[0], during which period the human population more than doubled from ~3.7B to ~7.8B and yet deaths caused by climate dropped threefold[1] (not 1/3 the rate; 1/3 in absolute number).

[0]: https://www.climate.gov/news-features/understanding-climate/...

[1]: https://library.wmo.int/doc_num.php?explnum_id=10989

On the scale of human civilisation, 50 years is hardly "long term".

Polonium by that ultra-short-relative-term reckoning is not only harmless as it you still feel fine 10 minutes later, but actually healthsome as you rather feel refreshed by the delicious green tea you just drank in that 5-star hotel bar.

We have also pumped a very large amount of long-lived fluorine compounds into the air, that will last for centuries. They have from 2500x to 25000x times the "greenhouse gas warming potential", kg for kg. They are mostly refrigerants (CFCs, HFCs, and soon their successors) and transformer insulation gas (SF6). Volcanoes do emit some amount of fluorine compounds, too.

We also have a great deal of methane leakage, which is usually cited as 25-100x, and we may soon have a lot of hydrogen leakage, at >100x. Rocket launches are installing water vapor, another one, into the stratosphere like never before.

So even if we got CO2 down to a pre-industrial level, we would still have heat forcing from the fluorine- and other compounds.

Capturing CO2 is kind of pointless until we get emissions under control. I.e., a dollar spent preventing emissions buys much more than a dollar spent capturing. Solar panels and wind turbines directly displace mass emitters of CO2.

Yes and: I understand that we want to prevent the non-human emissions from becoming a positive feedback loop. Meaning that at some tipping point, the thawing tundra, burning forests, and acidic oceans will continue to get worse, even if/when human emissions completely stop.

I don't know about all compounds but CFCs stay in atmosphere for about a century only and we've already banned them, and methane has a very short lifetime of about 12 years. So we 'only' need to control emissions of those to solve the problem.

On the other hand, as said, CO2 stays for centuries if not 1,000+ years so at this point net zero is only half the job though probably the hardest part.

Methane, at least, breaks down to CO2, no?

HFCs are not banned yet. They are responsible for 2500x CO2 forcing. Your car is leaking those right at this moment.

That is the point where we started adding greenhouse gases that lock in energy from the sun, we need to at least get back to those levels to start releasing some of the heat. Otherwise we're containing to add insulation to an oven that already overheating - you'd ideally want to take off all the insulation and the metal casing since you can't turn off the heat, but the casing isn't an option so we need to remove the insulation and hope it hasn't gotten too bad yet

The Keeling Curve is eye-opening for understanding our current versus (pre-)historical CO2 levels: https://tywkiwdbi.blogspot.com/2023/07/introducing-keeling-c...

One of the many misleading things done by climate scientists is to splice together data derived via different measurement methods.

The CO2 curve 800000 years back is an excellent example.

CO2 in air bubbles in ice will diffuse into the ice during the many millenia the ice have been stored under pressure. You can therefore expect the ice core CO2 to be lower than hypothetical atmospheric measurements at the same time.

The diffusion is expected to progress fastest at the start, and then more slowly.

Still the artifact is absolutely obvious as the CO2 concentration peaks are lower and lower the further back in time it goes.

Yet of course someone had to splice it all together and not even add error bars.

Not sure if you are trolling of really believe this to be true, but for anyone else assuming good faith: The diffusion aspect is (of course) well-modeled, see e.g. references under "past greenhouse gasses" at [0].

[0]: https://www.antarcticglaciers.org/glaciers-and-climate/ice-c...

Where is it well-modelled? Noble gasses will diffuse differently from CO2. And on-top of diffusion of course CO2 will make hydrogen bonds with water in the ice.

It is well-understood that many ice cores give the same relative shape of peaks of various gasses through time.

Going from there to claiming knowing the absolue concentrations without very large error bars, is just not science.

Also, btw, this one is fun:

"Carbon dioxide measurements from older ice in Greenland is less reliable, as meltwater layers have elevated carbon dioxide (CO2 is highly soluble in water)."

This is a very interesting read:

https://www.cambridge.org/core/journals/journal-of-glaciolog...

They have found some meltwater layers with unexpectedly large quantities of CO2 > 750ppm.

But they also show that there is unexpected heavy diffusion around the meltwater layers. And they argue very compellingly, that the ice core CO2 records have been smoothed through natural diffusion.

Why is this information not given when showing this graph?

>750 ppm CO2 is incredible, if that's true it's no wonder that interglacial maximums could have been 5 degrees warmer than present day.

What's the causal explanation behind that much CO2 though? Super-volcano eruptions?

They explain in the paper. It's very likely an artifact.

But from the layers around it, it becomes clear that through the years these high CO2 bubbles leak CO2 to nearby layers.

And so CO2 highs are diminished in the ice core record and CO2 lows have been raised.

But in the case it's not an artifact?

> Bottom line: we need large scale carbon capture quickly

The short term solution/bandaid is pumping SO2 into the stratosphere while we figure out carbon capture.

I do wonder if some of the "massed solar sail" ideas for terraforming Mars' atmosphere would work here (in short: use cellphone processors to build and launch a couple hundred thousand solar-sail equipped satellites).

Because it would be expensive, but it would kill several birds with one stone: we (1) prove whether the concept would work on Mars, (2) develop the technology to do it, and (3) unlike SO2 in the atmosphere, "switching it off" or modifying the scale of the effect can be done almost instantly (you could remove the swarm by having it fall back to an Earth orbit).

Is there anything left to really "figure out" about carbon capture? The tech works, it's just too expensive. Given a sufficient amount of cheap enough energy it could be scaled up as far as I understand.

As a layperson, it's just one more reason I so wish we'd invest in nuclear. Nuclear powered DAC plants might be the only way to scale it fast enough. Sure, it would still be expensive, but that's much cheaper than not massively reducing CO2 in the atmosphere.

I think it's way, way too expensive now, and it will probably take a few decades to get it down to practically useful cost levels.

Which is why keeping temperature down with SO2 during that time makes sense.

Based on our record of environmental interventions; SO2 sounds suicidal. But it only lasts a few days in the atmosphere so maybe it has an in built off switch.

Note that is for the stratosphere, not the atmosphere.

The mechanism is well known from volcanic eruptions, and it only lasts (from memory) 1-2 years in the stratosphere, so if something goes wrong, it can easily be tapered off.

See also this timeline of the last four inter-glacial periods: https://co2coalition.org/wp-content/uploads/2021/09/104-4000...

It also shows how crazy it would be if we get the projected 2-3 degrees average temperature increase. Even in a period where we'd expect to be going into a new ice age; instead shooting to a previously unseen high temperature.

On the other hand if we only have 2-3 degrees of warming, if that’s enough to prevent the next ice age, didn’t we just dodge a massive icy bullet? Might we not one day thank ourselves for doing something reckless and stupid that actually worked out?

Yeah a warmer climate brings all kinds of horrible changes. But food still grows in the northern hemisphere. A colder climate is arguably even worse for us.

By the way, that’s no excuse to keep doing what we’re doing. Limiting warning at 2-3 degrees will be nice. Things get really horrific above 4. At some unknown point feedback cycles really kick in and we go to 5-10 degrees and get completely fucked. We really have to not find out where that threshold is.

I didn't realize that the vast majority of the time Earth is in an ice age. What causes it periodically like this?

It’s mostly caused by Milankovitch cycles. Which are cyclic variations in our orbit around the sun.

The earth varies in distance to the sun and axial tilt and precession. Like waves, there factors can either overlap and somewhat cancel or they can stack for a larger effect.

ice ages didn't happen until after the asteroid strike. Antarctica moving into the south pole is likely a large part of it, but they don't really understand ice ages that well TBO. Anyhoo, the Earth was a lot warmer prior to the strike and we have been going through extinction events every 100k years.

By "the" asteroid strike I'm guessing you mean the one 66M years ago? There were definitely ice ages before that, likely including one or more Snowball Earth phases (the whole surface frozen): https://en.wikipedia.org/wiki/Snowball_Earth.

The planet is 4.5 billion years old! 400,000 years is just roughly 0.0089% of earth's history (and I rounded up!)

Humans are only about 300 000 years old though, so that part is much more relevant to our species than the rest.

There's no bullet to dodge. Minus human intervention, the next ice age would be in 50,000 years. Humanity will be either some unrecognizable scifi trope or, more likely, long gone by then. Planning for it is pointless.

The time scales for anthropogenic climate change and the previous temperature cycles are so different as to not be comparable.

I’m not saying to plan for it.

I’m just saying that a silver lining of the mess we’ve made is that we probably won’t have that ice age in 50,000 years. We’ve likely disrupted the cycle.

> Minus human intervention, the next ice age would be in 50,000 years. Humanity will be either some unrecognizable scifi trope or, more likely, long gone by then.

I think you are overestimating the probability that humanity would be "long gone by then". Even if a series of catastrophic events + climate change make life as we know it (modern civilization, globalized society/trade) untenable, humans are smart and many places on earth are reasonably forgiving to survival. Not saying it would be comfortable tho.

What I gathered is that if the gulf stream stops, warm water will no longer flow north and the ice sheets will grow explosively, triggering an ice age (the kind where thick ice sheets flow southwards). That would pretty much wipe out anything built in the northern half of Europe... although granted, I don't know if it was like a kilometer high ice sheet rolling our way or how fast it went in previous ice ages, it might be slow enough that it can be stopped and broken down before it causes damage.

Early onset of glaciation via warming instead of cooling. Counter intuitive idea.

It’s unclear that it would play out that way. One could look at what happened the last time it stopped to get some idea, but things are different this time. We have a lot more atmospheric CO2.

This is 99% conjecture. The current climate models do not predict those kinds of changes and most don’t have the fidelity to do so. Even the best models can’t account for simple things like aerosol pollution and they don’t have the resolution to determine the behaviour of ocean or atmospheric currents.

I don’t think many models predict much difference between 3 and 4 degrees, so I don’t think you can describe it as horrific.

IPCC predicts some local tipping points at 4C but global tipping points are much higher.

Can't believe they don't show a photo of what appears to be a 10 meter in diameter, 2.7km deep hole.

What an ice hole.

To be fair, is a photo of a hole that interesting?

I mean, there’s an entire multi-billion dollar industry dedicated to photos of holes.

Please don't do this here.

yes, people love pictures

Here's a picture of a cat sitting on the hole.

Its more like 5cm in diameter.

It's a bit hidden but there's at least a few cool pictures in the "Facts about the EGRIP camp" section (Click the + icon).

There you can see that the actual hole is ~10cm in diameter and the actual drilling site under the snow.

Or a video dropping a rock into it

The camera wouldn't take the picture, and then several of the scientists had to be sedated as they started acting strangely.

As long as they don't come up with schematics to build a white Marker...

For all we know that could be psyops by Lovecraft. Maybe it's not a white marker, it's a blue beacon.

There's a bright future in big holes.

Imagine what we can get our hands on if we could find a nice, cheap way to dig 10+ km down all over the place. The mantle is 2000+km thick. Our deepest mines are 3-4 km deep.

We could also harvest a ton of heat this way - and maybe even use it for garbage disposal. Master Of Orion 2 had the Deep Core Mines and Core Waste Dumps - maybe that's the way to go!

Is the idea of using a big hole for garbage disposal that we would dump the garbage into the molten core and let it burn? Or is it more about using the hole as a really deep landfill?

Do you know what a hole from the surface to the molten core is called?

An active volcano.

Scary thought but you’d (have to) stop digging way above the molten part.

It heats up way above 100C long before you get there, which should be plenty for geothermal energy.

I wonder if sustained high temperature exposure would gradually decompose plastic / toxic waste / other bad things into less harmful components.

Of course, heavy elements came from down there, so it’s probably not an issue to dump them back down. Just stay well clear of the water table!

I am of course not a geologist, and it’d be interesting if one could give a perspective on this.

I'm not sure how tall a column of water you need to trigger supercritical water oxidation, but the problem would be getting the oxygen down there.

Better to do that stuff at the surface, I think.

Yeah, I realized that after I commented, and when I googled it, the Quora answer I got basically boiled down to "you don't know what will come back out."

I always thought that was the scary part of a nuclear plant meltdown until I watch Chernobyl and realized poisoning the aquifer for a million years is a much more likely scenario.

Ice cores are a few inches across. The photo at the top of the article is not of the drill hole but of the hole they had to dig in the snow to get to the ice they actually drilled.

See the photo of the final ice core [1] to see how miniscule the actual drill hole is.

[1] https://science.ku.dk/english/press/news/2023/pay-dirt-for-i...

Why is is black and white though? also - how do they transfer energy to drill down 2.7km? or how the hell does it work?

See other comment, and "that's a fun thing to check youtube for", respectively =)

As mentioned in the article, the core was handled under red light to prevent any potential damage. Perhaps the decision to convert the photograph to black and white was made because otherwise it would have been black and red.

The article definitely makes it sound like they had “boots on the ground”. There’s a picture of muddy boots and the caption says they are covered in ancient mud.

That mud came up with the last core.

You need to clear a lot of snow before you can stand on the ice that you're drilling in (You can't drill straight if your rig's sitting on snow, you need to dig until you hit solid ground, and in this case the ground is ice). That's the "boots on the ground" part. They were physically there to do the drilling (as opposed to giant automated core drillers such as DISC[1], which don't require "boots on the ground" so much as they just require one or more operators to oversee operation)

The ancient mud's from hauling up the ice cores, not from standing 3 kilometers deep in a giant hole.

[1] https://icedrill.org/equipment/deep-ice-sheet-coring-drill

I’m not disputing the reality; it would be a bit ridiculous and I assume incredibly dangerous especially given the rate at which the whole thing is moving. I’m just arguing that the article is worded in a way that is encourages such a misunderstanding.

Just for fun:

Volume of ice = π * (radius)^2 * height

where radius = diameter / 2 and height is given in meters.

Volume = π * (10m / 2)^2 * 2700m

Volume ≈ 354,177.66 cubic meters

The density of ice is approximately 917 kilograms per cubic meter.

Weight of ice extracted = Volume * Density of ice

So, the weight of the ice extracted from the hole is approximately 324,856,152.42 kilograms.

Greta must be fuming.

In all seriousness though, ice cores are a few inches in diameter, not 10 meters. Unless they take one of those tunnel boring machines and send it vertically down through earth.

If drilling big holes for scientific research is your thing, I suggest https://usoceandiscovery.org/wp-content/uploads/2016/06/Casc... as an interesting read about earthquakes and tsunamis.

A quick summary:

  > Geophysical and hydrological observatories in sealed boreholes provide a powerful tool to understand the hydrology of crustal formations, a means measure the hydrologic signal from changes in volumetric strain, and a stable site for high quality seismic and geodetic instrumentation.

This data is not just useful on its own, but also when correlated to other research. For example, 400+ years ago there was a large earthquake (https://en.wikipedia.org/wiki/1700_Cascadia_earthquake) off the US Pacific Northwest coast (and corresponding tsunami in Japan) that is referenced.

That's a rate of about 4.3 centimeters per hour.

Can anybody elaborate as to why this process takes so long?

I've never drilled a hole with 10m diameter before, but I imagine they've been more careful about taking and studying cores than you were.

Surely you mean 10cm?

My word. I and at least one other poster here were misled by the picture at the top of the article.

But, for whatever it's worth, a trip to Wikipedia tells me that they took 2 years off, due to covid.

It's more realistic to say that covid caused logistics issue two summers in a row. The first summer was presumably 2020 when almost every country locked down. In 2021 things weren't much better and the various polar programs were dealing with both caution and a backlog of issues from the previous year.

The actual downtime may have been significantly less than 24 months but still could have killed progress for 36. There's a pretty small window that you can deploy for these sorts of operations.

Did you store the tube of ice?

it's a very high aspect ratio hole (267:1) so they have to peck-drill it and it takes a very long time to lift the drillbit to remove the swarf from the end

I'm going to see if I can work the term "swarf" into conversation tomorrow. (We all need goals.)

It's not a continuous 24/7/365 process. They have a drilling season each year, I believe about 6-8 weeks, have drilled at 2 different sites and been interrupted by the pandemic.

why was ice drilling interrupted by the pandemic?

Getting supplies such as food and shift changeovers?

International travel was not easy nor reliable during the pandemic, with many borders de facto closed or severely restricted, with quarantines, tests, etc.. needed. The drilling season involves moving an international team from each of their home countries to Greenland, then back again a few weeks later. So practically impossible to make sure the drilling season could happen with the crew required and then get them home again.

Every country I know of had special exemptions in place though, after the first few weeks of panic, for those who could supply credible written explanations.

As the hole gets deeper, the amount of time to bring up core sections and send the drill back down become significant. That combined with the previously mentioned short field season. Drilling more than a few hundred meters becomes very difficult logistically as well, especially in such a remote setting.

Like fetching the n-th element from a linked list by starting at the first node.

Who knew, drilling is O(N^2)

It's not O(N^2) is it? It can be a continuous line of ice being pushed up. Depending on the weight bearing ability of the lift and digging capacity, you would figure out a fixed distance after which you would place the buckets to carry up the ice.

Its an interesting interview question at the very least. (More complications arise as and how you get deeper into the ice).

You can't have a continuous line of ice coming up, unless you're digging for slush. Each intact X-meter core must be hauled up on its own, and then the drill has to go back down. The deeper you are, the longer it takes to haul up one core and send the drill back down. So, retrieving the cores is clearly O(N^2).

Drilling the core itself is O(N), but as you go deeper the core retrieval dominates. Not to mention everything getting more complex the deeper you go.

Anyone who has hung a heavy picture/frame? :-)

(you need to pull the drill out periodically to let the dust out, and the distance of that pull increases with depth. But it is O(K1 * N^2 + K2 * N) where K1/K2 are pull-out and drilling-in (both seconds per mm), and for short holes most of the time will be drilling not removing dust.

We need a couple more bore holes to do a Tower of Hanoi style question for interviews.

I believe the deeper the layer of ice, the thougher it is, so at the surface is relatively easy to drill but at those depths it might be like drilling on steel.

At approximately the same depth drilled, Antarctica e.g. EPICA @ Dome C yields 8 interglacials [0].

[0] https://en.wikipedia.org/wiki/European_Project_for_Ice_Corin...

There is a design for an ice-melting-slurry-bot that could be made, where the outer diameter of the bore is melted by heat/lasers - where the lasers/heat is also projected into a cone at the point of the bore-ing machine, where the center pipe is a vacuum to slurp up the slurry as it melts the ice around the bore-head...

You aren't going to be able to vacuum slurry up from several km down.

Even with a very small diameter hose/pipe?

The smaller pipe has less water in it, but the surface area the vacuum can act on is also smaller so the column of water equals out the same as with the larger pipe.

At sea level, that's about 30 feet deep. If you want to bring water up from deeper, you have to move the pump down the well and push the water up the pipe instead of trying to suck water up like the pipe's a straw.

That would ruin the core samples

We dont want the core samples intact (we want to kill microbiologics on the way down to the goal, which is the crust and determination for other vacuous caverns under the ice, via both vertical and horiz boring. and cameras in crytal lenses to withstand the heat or polarize against the lightwaves of the lasers such that they are clear and a good image can be seen.

/Sci-fi..

My original comment is my idea based on the 1960s patents for nuclear tunnel boring machines which use the reactor heat to exchange the tunnel walls to molten glass... (And I am really into DUMBS - as are many)

https://patents.google.com/patent/US3885832A/en

There are a lot of patents like this - so dont think this line of thought was abandoned, Hello Musk's Boring company... Good thing hes connecting State on a Deep level.

Would it theoreticaly possible to find frozen animals 120.000 years old with still intact DNA?

Yeah, DNA in ice has a half-life of a million years. Seems very much possible.

What does half-life mean in the context of DNA? One base pair corrupted / unrecoverable? Half of them?

half life generally means that within the time frame 50% of the material will have been destroyed or changed.

so it would mean that half of the dna might still be available after 1M years

To be meaningful, half-life needs a Markov assumption, i.e., that the past and future are conditionally independent given the present. Or, more simply, at each instant, forget the past and for predicting the future use only the present.

Some interesting work in the many contexts where half-life works would be to say what the Markov property says about the mechanism of the decay or whatever are trying to predict in the context.

Half of them. Which is still useful in biological samples that have billions of copies.

Yeah, you can still assemble a genome even if strands are broken. In fact this is done all the time as the size of the strands going into DNA sequencers are often only 100s or maybe 1000s of basepairs.

Where are you getting that figure? Everything I had ever read on the subject puts the half-life at more like 500 (five-hundred) years. While doing a quick double-check for this comment, it seems there was one sample with the unexpectedly long observed half-life of 15,000 years, still a couple orders of magnitude less than a million years. https://en.wikipedia.org/wiki/Ancient_DNA#Non-human_aDNA

I'm not an expert in this area but I do know a fair amount on the subject. I believe the section you linked is out of date.

The DNA we get back from old situations typically was preserved, by dryness/freezing, and it's still quite fragmentary. The actual "half life" of DNA is not that interesting- its the details of the DNA remnants that matter.

Preservation conditions might have some bearing.

This recent news article suggests nematodes actually surviving after 46K years in permafrost. https://www.scientificamerican.com/article/46-000-year-old-w...

That’s room temperature. Frozen DNA is significantly more resilient. https://www.pnas.org/doi/10.1073/pnas.0702196104

The oldest frozen mastodon found is only 30K years ago.

This isn't really "frozen animals" and everything was sort of mixed together so they had to compare remaining fragments to existing sequences:

https://www.nytimes.com/2022/12/07/science/oldest-dna-greenl...

Not an animal, icecore, or that old, but ancient plants has been grown from seeds from permafrost.[0] So who knows what might be found and analyzed from all the icecores.

[0] https://www.theguardian.com/world/2012/feb/21/russian-scient...

I love humans.

They somehow decided to start drilling, and not give up & get funding for 7 years.

We are a crazy but exciting bunch of organisms.

> We are a crazy but exciting bunch of organisms.

I read this as "crazy but extinct bunch of organisms"

Also read extinct. Ha. Would be cool to know how to detect and exploit these speed reading induced recognition errors to write things that force people to slow down or go extinct :)

>I read this as "crazy but extinct bunch of organisms"

That'll be true too, eventually. The way we're going now, it might not even be that long...

I think we should build a monument on the Moon with an archive of data of our cultures (including a copy of Wikipedia), built to survive for as long as possible, so that alien explorers can learn about us after we destroy ourselves, and learn how we managed to do so so they don't repeat the same mistake.

That’s because we are social animals. We tend to do things not only for ourselves, but also to contribute to the society we live in.

They can use this method to break the bedrock and reach the void - https://minecraft.fandom.com/wiki/Tutorials/Breaking_bedrock...

It is important to note that you need to be very careful near the void, as it is very hard to escape, and 64 blocks down you get instant damage which would get you killed.

what is the risk of uncovering ancient viruses and bacteria from permafrost that we don't have immunity to

Very very very low. Bacteria and viruses are normally very sensitive to their hosts, they have a kind of symbiosis that means they can't just arbitrarily infect any species they bump into.

Jumping between species does happen, and when it happens it can be a big problem (see COVID-19, Swine Flu), but there is something like 100 million different virus species out there [1], and only 200 or so are able to infect humans [2]. Despite constant interaction between people and all other species of viral host all over the globe, and millions of brand new new virus exposures daily, jumps are still so rare that they are decade-defining when they happen.

1. https://virology.ws/2013/09/06/how-many-viruses-on-earth/

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427559/

I read a book, How to Clone a Mammoth, by ancient DNA researcher Beth Shapiro.

If what she wrote holds true deep in these glaciers (which take a long time to form so they presumably weren't always buried so deep), then the answer to what the risk may be is "very remote". DNA and RNA disintegrates into very small tatters pretty easily, turns out, frustrating the reconstruction of ancient genomes. Bacteria are definitely dead on multiple counts and viruses will be shredded.

Here is an article from 2021 that covers that topic:

https://link.springer.com/article/10.1007/s42398-021-00184-8

From the conclusions: "... as shown by recent outbreaks of diseases caused by supposed to be extinct microbial pathogens immured in glacial ice for centuries, there is a serious risk for future epidemics (or even pandemics) to happen more often."

Negligible. You're far more likely to fall ill from bacteria in your garbage disposal or fungi in your bathroom.

>electromechanical drill designed to take 122 mm (4.8-inch) diameter ice cores

Interesting that they choose 122mm as the core size when designing the drill. It makes me wonder if its built from a decommissioned and repurposed 122mm artillery gun barrel.

Two numbers from the article: The oldest ice is 120000 years old. The ice is moving at 58 m/years.

If these numbers are correct the oldest ice has travelled almost 7000 km. Greenland isn't that large, and it did not shrink. The age estimate is probably correct.

The speed must have been a lot lower in the past?

Or it was moving in a different direction

I have a hard time trusting climate data from before we had satellites or other forms of precise automated recording. If climate scientists are telling us they _know_ detailed information about global atmospheric temperatures, greenhouse gas concentrations, etc. over millions years because they cored some ice from a select set of places on earth, I just don't know how an average person is supposed to believe that. It appears to the layman to be data generation on par with an episode of CSI where the lab somehow 'enhances' low res photos to high res.

Where are the million year long experiments demonstrating how ice and its contents changes over such long time spans, that vast majority of which we were not even conscious for as a species? It is too many variable to fit into any sort of computing technology today, and the science is mostly based on statistics which everyone knows can be twisted easily.

There are thousands and thousands of papers with specific models. Do you have specific criticism of any of them other than a hand-wavy "I don't understand them, so they are probably untrustworthy"?

so how do they know its not just a big rock covered in frozen mud with more ice below it

From the picture that looks like a pretty large hole... any chance that execrates the melting process by increasing the surface area? Or is it insignificant just curious if someone has thought about or done any calculations...

I’ve always wondered: what do they do if the shaft snaps somewhere in the middle?

This is more for oil drilling, but this is a possibility. https://www.drillingformulas.com/fishing-drill-pipe-procedur...

I'm not totally sure how systems work for drilling this deep, but typically ice core setups attach the coring apparatus to the surface via a cable that is spooled by a winch. The cable itself ends up being the heaviest part of the system.

> The researchers literally got mud from under the ice cap on their feet.

stop the presses!

why is this article written this way? a mixture of factual science and juvenile exuberance.

Finally, a new ice product for cocktail enthusiasts to fetishize.

Isn't this the basically the plot to the prequel of The Thing?

Digging too deeply has been a plot point in many stories.

There’s even an urban legend that a failed Soviet borehole project broke into ‘hell’

https://en.wikipedia.org/wiki/Well_to_Hell

Have a drink?

Please, if the title is going to be that, at least remove the capitalization from that "m", so it represents an unity instead of "millions of something undisclosed".

"so it represents an unity instead"

If you are going to be pedantic, that "an" should be an "a", no?

That’s what I was thinking, yes.

You have to think HOW you pronounce the word. The ‘u’ in “unity” is pronounced as “you” which starts with a consonant. Hence, you use ‘a’ not “an”.

I've always wondered this, as a non English native speaker. You could also say the "u" in unity is pronounced as "iu" which starts with a vowel and sounds the same as "you", so your reasoning sounds incorrect. Perhaps a better explanation is that the "iu" diphthong is already paired together, so attaching it to the "an" sound to form "aniu" doesn't roll off the tongue as well.

Correct, this particular diphthong and the substitution of "an" for "a" serve the same exact function, so having both would be redundant. If we were to look at a word that starts with u but doesn't have the diphthong, such as Ubuntu, then "an" is used.

I think unity is just a typo for unit, not that that changes this discussion.

But Y is a vowel?

Yeah, occasionally. The previous sentence uses it as both.

Sometimes...

Only when your mouth parts move a certain way to pronouce it: https://www.youtube.com/watch?v=I6As7KhrFQ4

English rules for using "a" or "an" depend on sounds used in the next word, not particular letters. "A unit" and "An hour" are easy examples that might trip people up when focused on the letters used in spelling, but if you sound it out, you can probably work out what sounds best.

And of course it's even more complex when you mix UK vs US English:

- an herb (US), where the "h" is silent

- a herb (UK)

Cue confusion about "an historic".

Hacker News capitalized the “M” by itself.

Thank you for pointing this out. I thought it was referring to the age of the samples taken before reading your comment. It made the abstract less disappointing.

I only clicked on the article because I thought it was the age of the samples too.

If something has a negative age, does that mean it is from the future?

I can't tell if you're joking, but negative numbers are used to represent years BC.

It responds to the comment "I only clicked on the article because I thought it was the age of the samples too." Age is "The length of time that a person or thing has existed." AD and BC are both absolute values from a zero point, both positive ("1 BC is year 0, 45 BC is year −44" [0]). A relative chronological dating by some phenomenological method such as radiocarbon or thermolumenescence might establish a negative date relative to some other known benchmark [1].

How might something dated from the future be found? I'm not certain, but maybe it has to do with aliens that are all the rage nowadays.

If I were 12 years old, I would have been born 12 years ago.

If I were -12 years old, I would be born 12 years from now.

0. https://en.wikipedia.org/wiki/Anno_Domini

1. https://en.wikipedia.org/wiki/Chronological_dating

Yeah, makes a lot of sense. Hadn't even thought about the difference between age and year when I wrote that.

Thanks.

Also, a space is needed.

> The numerical value always precedes the unit and a space is always used to separate the unit from the number.

The International System of Units. 9th edition, section 5.4.3, page 149. https://www.bipm.org/en/publications/si-brochure

Submitted title was "Researchers reached the bottom of ice sheet at -2670m after 7 years of drilling". I've reverted to the article title now, or rather a slightly rewritten version to omit the linkbait.

Our software did screw up the m->M thing. Sorry!

At the mountains of madness

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