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Ice core scientists in East Greenland reach bedrock

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Re: Ice core scientists in East Greenland reach bedrock

#151

Post by detourdog »

lumost wrote: post #148
detourdog wrote: post #130

Earlier quoted context omitted.

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 pond…

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 ide…

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.

Re: Ice core scientists in East Greenland reach bedrock

#152

Post by angiosperm »

elzbardico wrote: post #133
mytailorisrich wrote: post #98

Earlier quoted context omitted.

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…

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

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.

Re: Ice core scientists in East Greenland reach bedrock

#153

Post by thrashh »

sleet_spotter wrote: post #141
elzbardico wrote: post #133

Earlier quoted context omitted.

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

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.

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.

Re: Ice core scientists in East Greenland reach bedrock

#154

Post by nonethewiser »

sleet_spotter wrote: post #141
elzbardico wrote: post #133

Earlier quoted context omitted.

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

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.

“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.

Re: Ice core scientists in East Greenland reach bedrock

#155

Post by e_i_pi_2 »

elzbardico wrote: post #133
mytailorisrich wrote: post #98

Earlier quoted context omitted.

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…

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

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

Re: Ice core scientists in East Greenland reach bedrock

#156

Post by pinkmuffinere »

colechristensen wrote: post #150
sleet_spotter wrote: post #141

Earlier quoted context omitted.

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_…

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.

Re: Ice core scientists in East Greenland reach bedrock

#157

Post by orangepurple »

adolph wrote: post #72
sgirard wrote: post #7

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."

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_preh…

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.

Re: Ice core scientists in East Greenland reach bedrock

#158

Post by angiosperm »

adolph wrote: post #72
sgirard wrote: post #7

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."

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_preh…

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.

Re: Ice core scientists in East Greenland reach bedrock

#160

Post by angiosperm »

detourdog wrote: post #144
WhitneyLand wrote: post #69

Earlier quoted context omitted.

I’m not aware of any data that supports humans 120k years ago having a significant impact on the earths climate. I think even our ability to start fire at will is conclusively known to be only ~50,000 years ago.

I always wonder about that natural fission reactor in Gabon. They discovered the Uranium was pre depleted in particular mines. https://en.wikipedia.org/wiki/Oklo_Mine Fun to imagine the possibilities.

That was more than a billion years ago, so no.
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