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Author Topic: Is oceanic "bottom water" disappearing?  (Read 2209 times)

Offline yor_on

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Is oceanic "bottom water" disappearing?
« on: 24/04/2013 16:11:31 »
The Winter the Polar Vortex Collapsed.

The Thermohaline Ocean Circulation.

"Here’s a brief definition of ‘bottom water’:

 In oceanology, bottom water is by the ocean floor. It has characteristics are markedly distinct from the above layer in terms of oxygen content, salinity, bulk temperature (characteristic temperature), and hence density.  The Antarctic Bottom Water is the source of most bottom water in southern parts of Pacific Ocean, Indian Ocean and Atlantic Ocean, and even in parts of the North Atlantic. Bottom waters flow very slowly, driven mainly by slope topography and differences in temperature and salinity, especially compared to wind-driven surface ocean currents."


Antarctic bottom water disappearing.   

So, what does it mean?

The Antarctic Half of the Global Thermohaline Circulation Is Faltering.
So, is it complicated?
Very..

Damocles named it 'earth systems', if I remember right?
And stated that there was lot of information, still missing.

But, isn't this expected?
Not as I know.

It's field research, adapting models to facts.

Is it enough with me (cherry) picking some detail of it, to explain it to you?
Well, we all need to have some faith in ourselves.
But no. How could it be?

It's not enough.
=

So what do we need? All of us, deniers, skeptics, and believers all.
More information. More probes in space, and forget the costs, we will get it back. More field research, and more extrapolating, giving people a better chance to make educated guesses by themselves.
« Last Edit: 01/05/2013 08:28:08 by chris »


 

Offline yor_on

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Re: How complicated is it?
« Reply #1 on: 24/04/2013 16:29:27 »
And you better read those links.
 

Offline yor_on

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Re: How complicated is it?
« Reply #2 on: 24/04/2013 17:40:26 »
Two other, recent, articles I find interesting are

Continental-scale temperature variability during the past two millennia.   Real Climate discuss the article here. "The origin of the ‘PAGES 2k Network‘ and its activities can be found here and consists of nearly 80 individual collaborators. The Consortium’s collection of local expertise and proxy records was transformed into a synthesis by a smaller team of lead authors, but the large author list recognizes that the expertise of the wider team was essential in increasing the range of data used and interpreting it."

It can't have been easy work, and, as I see it, as a answer to those wanting us to ignore a man made global warming. Won't stop people from complaining about it of course :) and demand ever more. But then we're leaving science for beliefs. Because the final proof, according to science, would than be when we all see the consequences without doubt. As us living in a ice free world.

And then we have "Pace of shifts in climate regions increases with global temperature." discussing "Human-induced climate change causes significant changes in local climates, which in turn lead to changes in regional climate zones. Large shifts in the world distribution of Köppen–Geiger climate classifications by the end of this century have been projected. However, only a few studies have analysed the pace of these shifts in climate zones, and none has analysed whether the pace itself changes with increasing global mean temperature.

In this study, pace refers to the rate at which climate zones change as a function of amount of global warming. Here we show that present climate projections suggest that the pace of shifting climate zones increases approximately linearly with increasing global temperature. Using the RCP8.5 emissions pathway, the pace nearly doubles by the end of this century and about 20% of all land area undergoes a change in its original climate. This implies that species will have increasingly less time to adapt to Köppen zone changes in the future, which is expected to increase the risk of extinction."

In short, a global warming acceleration may kill species that won't get the time needed to adapt. Rather obvious in hindsight and discussed before this one too, but still interesting.
 

Offline yor_on

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Re: How complicated is it?
« Reply #3 on: 29/04/2013 23:53:05 »
With a risk of becoming boring. One more, and that one is about Greenland. Greenland and the Arctics are two of the fastest melting places I know of. Although i presume that there might be some mountains that may see the ice disappear even faster? The arctic is melting three times as fast as 1990 now, with Greenland, according to another older (2012) source, melting about five times as fast as in the 1990:s

"According to a new study published in the journal Geophysical Research Letters, Greenland’s melting glaciers and ice caps sent 50 gigatons of water gushing into the oceans from 2003 to 2008. This comprises about 10 percent of the water flowing from all ice caps and glaciers on Earth. The research comes on the heels of a study last year that showed the ice sheets of Greenland and Antarctica are disappearing three times faster than in the 1990s, and that Greenland’s is melting at an especially accelerated rate. In the new study, scientists were able to put an even finer point to the ice-melt situation by separating out the glaciers and ice caps from the ice sheet, which blankets 80 percent of the island. What they discovered is that Greenland’s glaciers are actually melting more quickly than the ice sheet."

From Greenland’s Glaciers Are Hemorrhaging Ice. (With space photos) 

The other, older study, from 2012 also had this to say.

""When combined, the full record of satellite data shows that the Antarctic and Greenland ice sheets have contributed just over 11 millimetres to global sea levels since 1992," said Shepherd. "This amounts to one-fifth of all sea level rise over the same period."

Greenland glacier melting 5 times faster than in 1990s. 

So, do you find it to be accelerating, or not?
And do you expect "what happens in the arctic to stay in the arctic", or not?
And the same can be asked for the antarctic, and there it is the west side that is worrying.

all together I would say it points to a accelerating scenario, faster than expected.
 

Offline yor_on

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Re: How complicated is it?
« Reply #4 on: 30/04/2013 13:10:50 »
Hmm, should have written Antarctica, not the arctics, although if Antarctica is deemed to melt about three times it former rate in the 1990s, and Greenland at 5x the rate from the 1990s then you can assume that arctic to be somewhere between 3-5x too.

"Arctic sea ice has declined at a rate significantly faster than global climate models have predicted.  Vinnikov et al. (1999) used the aforementioned GFDL and Hadley Centre climate models, forced by greenhouse gases and sulfate aerosols, to project how Arctic sea ice extent would change in the future.  As is the case with most climate models, they under-predicted the ensuing decline (Figure 8). 

In fact, the Arctic sea ice decline is already 27 years ahead of Vinnikov's projections.

...As Stroeve et al. (2012) discuss, newer climate models have made some progress in this area, but still cannot account for the full extent of the Arctic sea ice decline.

    "Previous research revealed that the observed downward trend in September ice extent exceeded simulated trends from most models participating in the World Climate Research Programme Coupled Model Intercomparison Project Phase 3 (CMIP3). We show here that as a group, simulated trends from the models contributing to CMIP5 are more consistent with observations over the satellite era (1979–2011). Trends from most ensemble members and models nevertheless remain smaller than the observed value."

This may be due to the difficulty in accounting for natural variations, or the physics associated with the domino effect discussed above, or both.  There are some regional models (i.e. see the model of Maslowski et al., also discussed here) which have had success in accounting for and predicting Arctic sea ice changes, but climate models overall have been too conservative in projecting the rapid decline in Arctic sea ice."

From    
Record Arctic Sea Ice Melt to Levels Unseen in Millennia.


Can we stop it? I don't think so myself.
Will it matter what we do?

On that one I will say yes. It will matter very much, especially for your kids, and their kids. You can see it as a fight between your personal demands for 'material happiness', relative your kids chances for the same in a changing world. There are all kinds of id**s out there, some believing that competition is all, and that we are meant to be at each others throats, until the last survivors proudly set their flag at the top of the scrap heap we made a living earth into.

You find this reasonable?
I don't.

What do you think your kids kids will say about it, and about you?
 

Offline yor_on

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Re: How complicated is it?
« Reply #5 on: 30/04/2013 13:30:27 »
And what more, it need us to change the way we think of Earth. It's not a place of infinite riches, and its resources can end. And whatever a 'market' is, it's not infallible, and we need to control and restrict it. A nation do not need to constantly consume more each year. We can all slow down a little, that would help a lot. It's like were all some idi*c mice in a cage running some labyrinth in where your markers for happiness is the way you can consume, and the 'market' does all it can to tell you that this is the way you should live. Because if you stopped, sat down, and asked yourself why you're running around, the 'market' and its 'wisdom' will come to a stop. And we shouldn't centralize, a centralized network of 'resources' is much more vulnerable than a decentralized. The Internet is a perfect example of a robust decentralized 'peer to peer' network, built to withstand a atomic war. Your closest nuclear power-plant is not.
 

Offline yor_on

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Re: How complicated is it?
« Reply #6 on: 30/04/2013 13:49:36 »
It's pretty stupid to demand us to become one supernation before anything can change, as the European community. That kind of thinking is to me medieval, going back to to consolidating resources, forcing people to accept changes for 'their own good'. It is also a perfect way to take the reins of this 'supernation' by some few. So it not only consolidate resources, and centralize, it also consolidates power, and freeze your personal ability to make a change locally. But politicans like it, lobbyists like it, all powers that are like it. And it doesn't matter if it is a democracy, not for this. It consolidates values into something unchanging.

It's like all values of power. Although you have a voice, and a right to vote, the reality behind it is still one of centralizations and power. The opposite of that is your right to education, free speech, and using your mind. That's a slow change, but once you started on that path you will not want to go back. Education and equality for all, that's what we need. That will also make you so much more able to decide for yourself. And decentralize it, share it.
« Last Edit: 30/04/2013 13:52:38 by yor_on »
 

Offline yor_on

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Re: How complicated is it?
« Reply #7 on: 30/04/2013 14:07:54 »
Heh, better stop this. I'm preaching, ain't I?
Never mind, we're here, just for a moment, but your choices do matter.
 

Offline yor_on

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Re: How complicated is it?
« Reply #8 on: 30/04/2013 15:22:47 »
Just one more thing. I heard this from my son, telling me what he thought a democracy meant. To him it was the way I must defend your views too, even when diametrically opposed to mine. And he's right, it builds not on us being one 'supernation' with 'one view'. It builds on us being able to think freely, speak freely, care for each other, and getting that education, enabling us to see why this matters.
 

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Re: How complicated is it?
« Reply #8 on: 30/04/2013 15:22:47 »

 

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