Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ice core scientists in East Greenland reach bedrock

news.ku.dk

Post reply on HN
Print view View original

221–230 of 356 posts

Re: Ice core scientists in East Greenland reach bedrock

#221

Post by Ilnsk »

aeroman wrote: post #122
ChuckMcM wrote: post #41

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…

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 en…

I wish I were a cloud person.

Re: Ice core scientists in East Greenland reach bedrock

#222

Post by crznp »

aeroman wrote: post #122
ChuckMcM wrote: post #41

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…

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 en…

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?

Re: Ice core scientists in East Greenland reach bedrock

#223

Post by biztos »

angiosperm wrote: post #158
adolph wrote: post #72

Earlier quoted context omitted.

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.

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.

Re: Ice core scientists in East Greenland reach bedrock

#225

Post by photochemsyn »

aeroman wrote: post #122
ChuckMcM wrote: post #41

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…

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 en…

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

Re: Ice core scientists in East Greenland reach bedrock

#226

Post by hcnews »

foota wrote: post #197
sleet_spotter wrote: post #127

Earlier quoted context omitted.

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.

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).

Re: Ice core scientists in East Greenland reach bedrock

#227

Post by photochemsyn »

earthscienceman wrote: post #91
ChuckMcM wrote: post #41

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…

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…

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...

Re: Ice core scientists in East Greenland reach bedrock

#228

Post by autokad »

kuprel wrote: post #180
slashdev wrote: post #176

Earlier quoted context omitted.

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, t…

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

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.

Re: Ice core scientists in East Greenland reach bedrock

#229

Post by FireBeyond »

wheelerof4te wrote: post #183
adolph wrote: post #72

Earlier quoted context omitted.

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…

"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 pas…

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.

Re: Ice core scientists in East Greenland reach bedrock

#230

Post by cstejerean »

javajosh wrote: post #189
anigbrowl wrote: post #110

Earlier quoted context omitted.

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/

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...

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.

Post reply on HN