Antarctic ice shelf Larson C is near its breaking point

[Lord of Planar]

You realize the energy isn't nearly as great at the poles as the equate, right? Then as Tim points out, we are starting with sub-zero ice. Not 0 C ice. More energy required yet.

I think we would be lucky to see 0.5% of the imbalance making it to the ice considering the albedo of ice, incidental angle, and starting heat content near the poles.

Now we also have thermal expansion of the ocean volume. That's an interesting calculation too.

 

[Visbek]

And just how is all of that 0.1% imbalance going to focus on the ice?

You realize the energy isn't nearly as great at the poles as the equate, right? Then as Tim points out, we are starting with sub-zero ice. Not 0 C ice. More energy required yet.

I think we would be lucky to see 0.5% of the imbalance making it to the ice considering the albedo of ice, incidental angle, and starting heat content near the poles.

Now we also have thermal expansion of the ocean volume. That's an interesting calculation too.

"Focus on the ice?" "Sub-zero ice?" Are you for real?

You set the parameters here. You asked "how many years, at what change in radiation, would trap an additional 3.66 x 10^23 joules on the Earth?" You asked a basic question, to illustrate a point ("it's a lot of energy!") I gave a basic answer, to illustrate a point ("a small change will trap a lot of energy").

Your request to move the goalposts is denied.

 

[Lord of Planar]

"Focus on the ice?" "Sub-zero ice?" Are you for real?

You set the parameters here. You asked "how many years, at what change in radiation, would trap an additional 3.66 x 10^23 joules on the Earth?" You asked a basic question, to illustrate a point ("it's a lot of energy!") I gave a basic answer, to illustrate a point ("a small change will trap a lot of energy").

The 3.66 x 10[SUP]23[/SUP] joules is just the heat of fusion. That is the energy required to melt that much ice. Just what percentage of the earth energy imbalance do you think would be available for that result?

Your request to move the goalposts is denied.

And we are speaking real world, not hypothetical. I did not move the goalpost.

-----
It takes an amazing amount of heat.

3.66 x 1023 joules of heat
-----

then

-----
Just how much of an energy balance for how long will it take to melt that much ice.
-----

Now I misstated there, it should have read "Just how much of an energy imbalance for how long will it take to melt that much ice," and this is implied for the earth system. Not just the local area.

The isolation of the energy of the Antarctic is probably some where around 12% of the total. The albedo of the Antarctic ice is probable around 0.85, leaving about 15% of the regional imbalance absorbed. 0.12 x 0.15 = 0.018, or 1.8% of the imbalance is available as heat for melting the ice. This makes your 67 years over 3,700 years.

Now of course, there are other factors at play. I mentioned the thermal expansion, and there is also a convective heat exchange between the water and ice where the sheet ice meets the shelf ice, and the convective exchange between the air and ice, but thermal expansion is the only one of these three with any significance.

Rounded to two significant digits, the average ocean depth is 3,700 meters deep. To get 10 inch rise in sea level from thermal expansion is to change the 3,700 number to 3,700.25 meters.

3,700.25/3,700 = 1.000067568, or a 0.0068% increase. This is for an average total ocean change.

So, it takes well under a 0.01% increase in ocean volume to rise the sea level by 10 inches. This is likely most of the sea level rise we have seen, for the changes in solar radiation and lag times for equalization. With it taking around 1,000 years for the oceans to complete a cycle of movement, this is a very slow process for equalization.

Now the ocean varies in temperature by depth, but this is the more likely reason we sea sea levels rise and fall over time outside of moving in and out of ice ages.

 

[Tim the plumber]

Math for what, exactly?

What equation, exactly, do you want us to solve?

How does throwing an incomplete word problem establish your bona fides?

Try this;

What amount of water/ice melt would be needed to cause a 10m inch sea level rise?

How much energy would that need to melt the ice?

How much energy inbalance does the IPCC/consensus say we have that is due to global warming?

How long would that take?

Does that make the question clear?

 

[Visbek]

The 3.66 x 10[SUP]23[/SUP] joules is just the heat of fusion. That is the energy required to melt that much ice. Just what percentage of the earth energy imbalance do you think would be available for that result?

Why are you making this a scavenger hunt?

If you want a genuine answer to a genuine question, then you need to ask the entire question, with all the relevant parameters.

we are speaking real world, not hypothetical. I did not move the goalpost.

If we are speaking of the real world, then we know that global temperatures are already warming enough (in the atmosphere and oceans) to cause the melting of global ice, both at the poles and in various glaciers around the world.

Since I am not (and do not claim to be) a trained climatologist, and if you want actual accurate answers based on projections informed by empirical observations, I'd have to find some academic research which provides the answers you want. Or am I supposed to ignore empirical evidence, and continue your mathematical scavenger hunt instead?

It takes an amazing amount of heat.

I have absolutely no doubt that is the case.

However, it takes an amazing amount of extra heat trapped in the atmosphere to increase global temperatures by 0.85° C. And that is what's happened since 1880.

We should also note that sea levels have risen by 8" since 1880. That's a lot less than 3700 years, no...?

3.66 x 1023 joules of heat

Uh huh

So, more napkin (restaurant?) math. Roughly speaking, it takes 417 kJ to increase the temperature of 1 kg (1 liter) of ice from 0° C to 20° C. Let's use this as a high estimate.

All of the ice in Greenland is estimated at 2.85E18 kg; if it all melted, sea levels would rise an estimated 23 feet (276"). To increase sea levels by 10", we need to melt 1.03260869565214E17 kg of ice.

That requires 4.30597826086942E22 joules.

Let's take my previous figures as a benchmark. Reducing radiation to space by 0.1% adds 1.49472E19 joules per day. That amount of energy would take 2,880 days, or a mere 7 years, to trap that much extra heat.

As you noted, that's not all going to go directly and exclusively to glaciers that will melt directly into the oceans. However, if 10% of it reaches those glaciers, then we've got 10" of sea level increase in 70 years.

Obviously, this is a vast oversimplification. For example, land-based glaciers that flow into the ocean do not need to melt to raise ocean levels -- even if they remain frozen, a large enough glacier would displace ocean water, and raise ocean levels long before it actually melts.

Anyway... I'm sure that the radiation and polar absorption figures are not correct, so it's probably just a coincidence that I'm in the right neighborhood. However, it does at least show that the "amazing" amounts of energy required can be conceivably trapped in the Earth's atmosphere.

More importantly, though, is that it has happened. We know sea levels have risen 8" since 1880. We know global temperatures, in the atmosphere and oceans, are rising. We know this is producing feedback effects, and we are already seeing them. Rising global temperatures are almost certainly responsible for the crack in the Larsen C ice shelf, which is thousands of years old... and the topic of this thread.

Even as I type this, the crack is accelerating; there are only 8 miles left, and it could calve any day.. It's not clear if this will destabilize the entire shelf, as happened with Larsen B. If it does, then the land-based glaciers will likely be able to flow into the ocean, and this will accelerate the rate of sea level rise.

So yes, I'm confident that 10" of sea level rise is much closer to 70 years, than 3700 years.

 

[Visbek]

Try this;

What amount of water/ice melt would be needed to cause a 10m inch sea level rise?

1.03260869565214E17 kg

That said, glaciers don't have to melt to increase sea levels. Land-based glaciers that flow into the oceans displace water, which also raises sea levels.

Plus, when water is heated, it expands. As the oceans trap more heat, they expand, which also increases sea levels.

How much energy would that need to melt the ice?

4.30597826086942E22 joules

How much energy inbalance does the IPCC/consensus say we have that is due to global warming?

Almost all of it.

Pursuing this route, I get slightly different figures than my previous examples, but not by much.

NASA puts our current imbalance at 0.58 W/m[sup]2[/sup] during the latest solar minimum. The Earth is 510 trillion m[sup]2[/sup], approximately half exposed to the sun at any given time. That's 1.479E14 joules per second, or 1.277856E19 per day. (This is higher than the previous napkin-math estimate of 1.0612512E22 trapped per day, so I might not have been too far off.)

I'm getting 3,369 days, or 9 years, to trap 4.30597826086942E22 joules. If we say that 10% of the energy is absorbed by the glaciers, it'd take 90 years.

As I've already stated, I'm not a climate scientist, I do not pretend to be one, and I have no doubt someone in the field could do a much better job. There is no way this could constitute a viable model, nor do I think anyone should treat it as such. That said, I don't think I am off by orders of magnitude.

Does that make the question clear?

It does. But it's not clear why Planar decided to play Peek-A-Boo with his question.

 

[Lord of Planar]

Message over 5000 characters... splitting into two.

part 1:

Why are you making this a scavenger hunt?

If you want a genuine answer to a genuine question, then you need to ask the entire question, with all the relevant parameters.

If you don't already know the basic parameters, why are you debating this topic?

If we are speaking of the real world, then we know that global temperatures are already warming enough (in the atmosphere and oceans) to cause the melting of global ice, both at the poles and in various glaciers around the world.

We know???

You mean that's what the indoctrination by pundits tell you...

have you verified that they are not lying to you?

There are several variables in the climate system. None of them have affected the south polar temperature enough to induce any significant temperature related melting.

Since I am not (and do not claim to be) a trained climatologist, and if you want actual accurate answers based on projections informed by empirical observations, I'd have to find some academic research which provides the answers you want. Or am I supposed to ignore empirical evidence, and continue your mathematical scavenger hunt instead?

The math is solid. It takes a given amount of energy to melt enough zero degree ice to zero degree water to raise the sea level by a quarter of a meter. Since only a small percentage of the earth energy balance can achieve such a goal, the time required is significantly longer than applying 100% of the energy imbalance to it.

I have absolutely no doubt that is the case.

However, it takes an amazing amount of extra heat trapped in the atmosphere to increase global temperatures by 0.85° C. And that is what's happened since 1880.

We should also note that sea levels have risen by 8" since 1880. That's a lot less than 3700 years, no...?

The mass of the atmosphere is minuscule compared to the mass of water and ice.

Uh huh

So, more napkin (restaurant?) math. Roughly speaking, it takes 417 kJ to increase the temperature of 1 kg (1 liter) of ice from 0° C to 20° C. Let's use this as a high estimate.

All of the ice in Greenland is estimated at 2.85E18 kg; if it all melted, sea levels would rise an estimated 23 feet (276"). To increase sea levels by 10", we need to melt 1.03260869565214E17 kg of ice.

That requires 4.30597826086942E22 joules.

Let's take my previous figures as a benchmark. Reducing radiation to space by 0.1% adds 1.49472E19 joules per day. That amount of energy would take 2,880 days, or a mere 7 years, to trap that much extra heat.

As you noted, that's not all going to go directly and exclusively to glaciers that will melt directly into the oceans. However, if 10% of it reaches those glaciers, then we've got 10" of sea level increase in 70 years.

The average ice is probable starting at -20C, so how about starting with 500 kJ/kg...
The albedo of the Greenland ice is in the neighborhood of 0.8, which means ic can only receive 20% of the thermal emissions in the area. The latitude if Greenland and width of longitude only allow for a small fraction of the radiative imbalance. Well under 1% of it. I will contend without reservation that the soot and other aerosols falling out of the sky on the Greenland ice, melt the ice much greater than any radiative change by greenhouse gasses.

 

[Lord of Planar]

Part 2:

Obviously, this is a vast oversimplification. For example, land-based glaciers that flow into the ocean do not need to melt to raise ocean levels -- even if they remain frozen, a large enough glacier would displace ocean water, and raise ocean levels long before it actually melts.

And there is an approximate balance between precipitation making more ice, and what flows into the oceans.

Anyway... I'm sure that the radiation and polar absorption figures are not correct, so it's probably just a coincidence that I'm in the right neighborhood. However, it does at least show that the "amazing" amounts of energy required can be conceivably trapped in the Earth's atmosphere.

More importantly, though, is that it has happened. We know sea levels have risen 8" since 1880. We know global temperatures, in the atmosphere and oceans, are rising. We know this is producing feedback effects, and we are already seeing them. Rising global temperatures are almost certainly responsible for the crack in the Larsen C ice shelf, which is thousands of years old... and the topic of this thread.

Can you say "thermal expansion?"

Even as I type this, the crack is accelerating; there are only 8 miles left, and it could calve any day.. It's not clear if this will destabilize the entire shelf, as happened with Larsen B. If it does, then the land-based glaciers will likely be able to flow into the ocean, and this will accelerate the rate of sea level rise.

So yes, I'm confident that 10" of sea level rise is much closer to 70 years, than 3700 years.

The crack is only a small part of the shelf, I don't see how it will increase the flow significantly, or make the whole shelf calve. If anything, I would think with less tidal forcing transmitted to the upstream ice, the flow would slow down. Not speed up.

Please take your indoctrination blinder off.

 

[Visbek]

If you don't already know the basic parameters, why are you debating this topic?

I don't know the parameters of YOUR QUESTION.

We know???

We know.

have you verified that they are not lying to you?

Did I mention that whole "moving the goalposts" thing?

There are several variables in the climate system. None of them have affected the south polar temperature enough to induce any significant temperature related melting.

So... There isn't about to be a massive chunk of ice calving off of Larsen Ice Shelf C? It's what, a big fake? Wow! What a relief!

:roll:

There are significant glacial losses around the globe. Greenland, Himalayas, Cascades, Rockies, Europe etc. I guess I should pay no attention to the man behind the curtain, right?

The math is solid. It takes a given amount of energy to melt enough zero degree ice to zero degree water to raise the sea level by a quarter of a meter. Since only a small percentage of the earth energy balance can achieve such a goal, the time required is significantly longer than applying 100% of the energy imbalance to it.

Your claim that it is so small that it would take thousands of years directly contradicts the empirical evidence. You do understand that, right?

The mass of the atmosphere is minuscule compared to the mass of water and ice.

Sure. So what? We're not talking about the amount of energy required to increase global temperatures. I'm pointing out that sea levels are already rising.

The average ice is probable starting at -20C, so how about starting with 500 kJ/kg...

That makes almost no difference whatsoever. Again, I know I'm off, but not by orders of magnitude. And we aren't considering dozens of other factors that can accelerate the process, like feedback loops, rising CO2, that land glaciers flowing into the oceans will raise sea levels without melting the ice, and so forth.

 

[Visbek]

And there is an approximate balance between precipitation making more ice, and what flows into the oceans.

So you are yet again changing parameters. Why should I take you seriously again?

Can you say "thermal expansion?"

And what caused that thermal expansion? Think about it for a minute. It'll come to you. Maybe.

The crack is only a small part of the shelf, I don't see how it will increase the flow significantly, or make the whole shelf calve. If anything, I would think with less tidal forcing transmitted to the upstream ice, the flow would slow down. Not speed up.

sigh

In 2002, a section of Larsen Ice Shelf B calved. It destabilized the entire ice shelf, which resulted in land ice flowing into the ocean. This contributed to rising sea levels.

Somewhere between 9% and 12% of C is about to calve. When it does, it is possible it will destabilize the entire shelf, and we'll have a repeat of B. If all of the ice held back by C goes into the ocean, that alone will raise sea levels by 4".

So tell us all... When are you moving to Miami? Key West, perhaps? How about Galveston? It's not like any of these areas will be threatened by sea level rise due to global warming....

 

[Threegoofs]

So you are yet again changing parameters. Why should I take you seriously again?



And what caused that thermal expansion? Think about it for a minute. It'll come to you. Maybe.



sigh

In 2002, a section of Larsen Ice Shelf B calved. It destabilized the entire ice shelf, which resulted in land ice flowing into the ocean. This contributed to rising sea levels.

Somewhere between 9% and 12% of C is about to calve. When it does, it is possible it will destabilize the entire shelf, and we'll have a repeat of B. If all of the ice held back by C goes into the ocean, that alone will raise sea levels by 4".

So tell us all... When are you moving to Miami? Key West, perhaps? How about Galveston? It's not like any of these areas will be threatened by sea level rise due to global warming....

Personally, I love the fact that he's now a glaciologist who can assess glacial flow after ice calving.

It's impressive since he also considers himself a world class climatologist, oceanographer. Md paleoclimatologist.

 

[Tim the plumber]

There are significant glacial losses around the globe. Greenland, Himalayas, Cascades, Rockies, Europe etc. I guess I should pay no attention to the man behind the curtain, right?

There are no significant amounts of ice (in terms of potential impact on sea level if they all melted) in the Himalayas, Cascades, Rockies(well 2cm worth there) or Europe.

 

[Jack Hays]

Antarctic
[h=1]Scientists discover 91 volcanoes below Antarctic ice sheet[/h]From The Guardian This is in addition to 47 already known about and eruption would melt more ice in region affected by climate change This is in addition to 47 already known about and eruption would melt more ice in region affected by climate change Robin McKie Saturday 12 August 2017 18.11 EDT Last modified…

 

[Jack Hays]

[h=2]Antarctica – 91 volcanoes coincidentally found under glaciers warming “due to climate change”[/h]
It’s possibly the densest concentration of volcanoes in the world, some as high as 4km and we didn’t even know these existed til recently. Despite that overwhelming ignorance, we’re 97.00% certain that all the warming in Antarctica is due to your car and airconditioner. Robin McKie, The Guardian writer, talks about the recent discovery of so many volcanoes under the ice. Not surprisingly, we have no data on how active these volcanoes are. However because we *know* climate change is definitely wrecking Antarctica, it follows that your car, air conditioner and pet dog could melt more ice, take the pressure off the tectonic plate and set one off. Then things will really get out of hand.
Anyhow, it’s just a coincidence that all the warming in Antarctica is where the volcanoes are.

Warming in Antarctica | New volcano discoveries
​

Spread the hagtag #allvolcanosmatter.
[h=3]From The Guardian: Scientists discover 91 volcanoes below Antarctic ice sheet[/h]Scientists have uncovered the largest volcanic region on Earth – two kilometres below the surface of the vast ice sheet that covers west Antarctica.
The project, by Edinburgh University researchers, has revealed almost 100 volcanoes – with the highest as tall as the Eiger, which stands at almost 4,000 metres in Switzerland.
Geologists say this huge region is likely to dwarf that of east Africa’s volcanic ridge, currently rated the densest concentration of volcanoes in the world.
These newly discovered volcanoes range in height from 100 to 3,850 metres. All are covered in ice, which sometimes lies in layers that are more than 4km thick in the region. These active peaks are concentrated in a region known as the west Antarctic rift system, which stretches 3,500km from Antarctica’s Ross ice shelf to the Antarctic peninsula.
Who’s responsible for lava?
(Regulate now!)

 

[Threegoofs]

Funny. Deniers were arguing before that there is NO warming in the Antarctic, and there's actually ice gain.

Now somehow volcanoes under two miles of ice are causing warming.

 

[Jack Hays]

Funny. Deniers were arguing before that there is NO warming in the Antarctic, and there's actually ice gain.

Now somehow volcanoes under two miles of ice are causing warming.

I have consistently pointed out that a "warming" effect on Antarctic ice ascribed to AGW by advocates was likely instead a product of volcanic action.

 

[Threegoofs]

I have consistently pointed out that a "warming" effect on Antarctic ice ascribed to AGW by advocates was likely instead a product of volcanic action.

Except when you copypasta stuff that says there's no warming.

 

[Jack Hays]

Except when you copypasta stuff that says there's no warming.

Yes. Do you understand you just made my point?

 

[Threegoofs]

Yes. Do you understand you just made my point?

Yes. The Antarctic is warming because of volcanoes except that it's not warming at all and the ice isn't melting except if it is its volcanoes and it's ALL A GIANT CONSPIRACY!

Is that close?

 

[Jack Hays]

Yes. The Antarctic is warming because of volcanoes except that it's not warming at all and the ice isn't melting except if it is its volcanoes and it's ALL A GIANT CONSPIRACY!

Is that close?

The word "conspiracy" appears often in your posts but never in mine.
Effects on Antarctic ice attributed to AGW are more likely the result of volcanic activity.

 

[Jack Hays]

[h=1]New map of Antarctic geothermal heat suggests Steig & Mann 2009 weren’t measuring ‘global warming’[/h]This is quite interesting. Remember the claim in on the front cover of Nature in 2009 by Steig and Mann that Antarctica was warming, thanks to that “special Mannian PCA math sauce” that was applied to air temperature data to smear surface temperature trends over the entire continent? It was dashed by climate skeptics who…
Continue reading →

 

[Threegoofs]

[h=1]New map of Antarctic geothermal heat suggests Steig & Mann 2009 weren’t measuring ‘global warming’[/h]This is quite interesting. Remember the claim in on the front cover of Nature in 2009 by Steig and Mann that Antarctica was warming, thanks to that “special Mannian PCA math sauce” that was applied to air temperature data to smear surface temperature trends over the entire continent? It was dashed by climate skeptics who…
Continue reading →

Looks like Jack is spamming threads again with another denier blog cut and paste.

 

[Jack Hays]

Looks like Jack is spamming threads again with another denier blog cut and paste.

Heat flux distribution of Antarctica unveiled by Yasmina M. Martos, Manuel Catalan, Tom A Jordan, Alexander Golynsky, Dmitry Golynsky, Graeme Eagles, David Vaughan is published in Geophysical Research Letters here:
Heat flux distribution of Antarctica unveiled - Martos - 2017 - Geophysical Research Letters - Wiley Online Library
Abstract
Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent-wide heat flux maps have only been derived from low-resolution satellite magnetic and seismological data. We present a high resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small-scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high-resolution heat-flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice-sheet dynamics and sea-level change.