Dramatic collapse of Antarctic ice shelf linked to global warming

the latest in what happened down there in 2002...

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maybe :huh: we could tow the glacier to the equator and provide fresh water for th epeople there as well as cool the equator a bit

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inventing and writing forum
You dont know how little you know.
till you know enought
to know that you still know nothing

Any particular part of the equator lacking water?
It would certainly add some interest to what I imagine would be rather dull shipping news...
>wonders< what might an injection of cold, fresh water do to the ENSO (El Nino-Southern Oscillation) or the Gulf Stream? h34r:

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The evidence keeps coming in...
This one from the BBC, reminds me of a couple of documentaries a few years back, on the island communities of the Aleutians, and the Inuit and Lapps...

Alaskan people tell of climate change
By Kate Bissell BBC Radio 4
Last Updated: Sunday, 7 August 2005, 14:42 GMT 15:42 UK

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This is not evidence. It is speculation.

Would you be able to understand the climate of Titan with only 2 hours of data sent back by Huygens?

Would you be able to draw a reliable picture of the corporate climate in the Chrysler company with data only from the late 1970's?

Can you truly understand what is happening in our climate with but 200 years of records, and only a couple decades which are accurate and encompassing?

It might be right, but might not. Lets keep an eye on it.

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~ cogito cogito ergo cogito sum ~

Nothing in life is good nor bad; thinking makes it so.

Ditto aeolus. Is the climate naturally cyclical and we are just on a natural warming swing post-ice age, or is it caused by man? Well, there were ice-ages and hot periods before us, and now we're just out of an ice-age (on a geological time scale) and the world is warming up... Hmmm. Which is more likely?

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...and we'll be saying a big hello to all intelligent life forms everywhere; and to everyone else out there, the secret is to bang the rocks together, guys...

Sorry, John, but we're not "just out of an ice-age (on a geological time scale)". We're about 12,0000 years into an interglacial, the last several of which have lasted about that long.

You are right to question whether the currently observed warming could be natural, though. Even though we're at a stage in the cycle that one could expect cooling, maybe this is a natural trend - a slightly longer interglacial (for example, not all sunspot cycles are exactly 11 years long). But when you look at the data, the last couple of decades are clearly an anomaly. Nothing like this has ever happened naturally in the past. And it was predicted by scientists before it happened. That should increase their credibility, but to people who want to ignore it nothing like that matters.

How many record warm years in a row will it take? How many glaciers have to disappear completely before people will stop taking refuge in that excuse "It might just be a Natural Fluctuation", without even looking at the data to see if "Natural Fluctuations" like this had ever, ever happened in the past? My cynical side says the answer is "All of them, and then some."

All good points so far...
Sorry, TheThorn, but JohnL is correct - in geology, 1 million years is a very short time - and I think it's closer to 12,000 years...
In trying to understand the geologic history, we found episodes of glacial advances/retreats in (geologically-speaking) very recent times (these are all surface uncompressed, unlithified, deposits and terrains) - and it points to a ~100,000 year cycle of advance/retreat - we call it the Milankovic cycle. An unknown (as yet) number of these cycles, added together make an Ice Age (that is where much of the earlier confusion comes from, because natural historians and geologists were labelling each individual advance as an 'ice age' and each retreat as an 'interglacial').
Overlying the Milankovic cycle are other cycles, some on smaller scales, some on very much larger scales - in the case of major Ice Ages, the total duration is on the order of 10 million years, and the Interglacials extend to at least 100 million years...and over that are even larger cycles...corresponding roughly to the 3:2 resonance of the galactic:density wave rotation.
The most recent Ice Age (cycles of advance/retreat) began about 10 million years ago; the question is whether the Ice Age has completed (ie, whether we are moving into a major Interglacial), or whether there will be another advance due in about 85,000 years)...the reason for the question is because the rate and extent of warming is rather different in either case.
The serious debate should not be whether we are causing global warming - because global warming would be happening anyway (okay? we clear on that?) - the debate is whether (and by how much) we are accelerating (or adding to) the 'natural' process.

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Where did that extra zero come from? I meant 12,000.

And of course, 1 million years is brief, geologically speaking, I wasn't arguing with that. What I was arguing with, and what both of you seem to have wrong, is the idea that the current interglacial is just starting. In fact, if past cycles are anything to go by, it's almost over.

Check out this article, especially the graph under "Interglacials". They mention in the article that the common wisdom is that interglacials last about 12,000 years, pretty much what I said. They mention that other people argue that the current interglacial might not be typical. That's exactly what you need to argue if you want to conclude that the current warmng is natural. Because if this interglacial was typical, we should be cooling off right now. Maybe not on a decade to decade basis (there are short term variations in climate), but the thousand year type trend should be down.

Oh, you know about Milankovic cycles? Then you're aware that the insolation at 65 degrees North Latitude peaked for the current cycle 9,000 years ago. It's been going down since then. Milankovic cycles DO last about 100,000 years - but that's the whole cycle, not the interglacial part of it, like you seem to think. They cycle is made up of about 85-90,000 years of glaciation followed by 10-15,000 years of relatively warm weather. And we're on the down side of the current one.

Nope, we're not clear on that. In fact, I think the exact opposite is true. The cycles we've experienced in the past, if they continued should have us cooling right now. That's why people were talking about a return to ice-age conditions in the '60s - they had come to understand Milankovic cycles.

On the other hand, paleo-climatic records show another occasion when the Earth experienced a rise in global temperature like the one we're experiencing now, over what appears to be a short time frame, like the current one. It was at the end of the last glaciation. That was natural, so could this be natural too? Well, that one was bouncing off the bottom of the temperature charts, and this one is starting from a peak. Doesn't look the same from here. We're charting new territory, warmer than we've been since this current ice age started, a couple of million years ago.

It could be that we just happen to be living at the end of a couple of million years of winter. More likely, this is not natural. Either way, it certainly looks like a break from the cycles of the last couple of million years.

TheThorn, my apologies ('85,000 yrs'? where did I get that? ptooi!) - that's what I get for trying to carry on more than one conversation at a time (can't walk and chew gum... :wacko: )

I checked the article; thanks for that, it's got some good stuff.
-from the Wikpedia article linked in TheThorn's post above:

and, a bit further along...
"folk wisdom" - something like the "folk wisdom" of the Inuit, Aleutian, and Lapp, perhaps?
The last figure (50,000 years) is the one I was looking for, that's the figure I used in a 2001 student paper - I should probably point out that my view (as a mere student of earth sciences) is that the current Ice Age is not yet completed, but I remain open to the possibility that it might be...
a bit further...
so, if they can't all agree... :blink: ...why should we expect to?
I also find this link, which has the same article, and a bit more...answers.com
...including a table of timespans of the more recent glacial advances('glacials')/retreats ('interglacials'), given as thousands of years before present - I've converted those times to relative spans and they are (from the most recent, and preceding...)
glacial 'spans' = 55,000; 50,000; 70,000; 140,000; 10,000; 15,000...
interglacial 'spans' = 60,000; 50,000; 30,000; 70,000; 35,000...
:blink: not real consistent in any fashion, is it?
I found a number of papers that agree with a 9000BP insolation peak (ie, plus or minus a couple of thousand years), so no argument there
The National Oceanographic and Atmospheric (Administration? NOAA) offer this for consideration: "...Warming at the end of glacial periods tends to happen more abruptly than the increase in solar insolation. There are several feedbacks that might be responsible for this..."; the full article can be found here
From here
we get:
"The present ice age commenced approximately 2.5 million years ago and its occurrence defines the Quaternary period of Earth history..." and "... a 60-million-year period of generally cooling global mean temperatures, culminating in the ice age that characterizes the Quaternary..."and "...periods between the ice ages are associated with high levels of atmospheric greenhouse gases. This distinction has led some workers to consider the Earth’s history as representing a series of shifts between "icehouse" and "greenhouse" climatic megacycles. For the overwhelming majority of the Earth’s history, its climate has been in a greenhouse state..."

and, backing up TheThorn's argument "...Over the past few decades it has been recognized that major climate changes were numerous during the Quaternary ice age, and involved dramatic shifts between colder glacial conditions and warmer interglacial conditions. The glacial phases are typically long lasting (many tens of thousands of years) in comparison with the interglacial phases, which typically last for roughly ten thousand years..."

and, just to show that we could be almost anywhere in the climate variation/cycle/whatever..."...The records collected from both Greenland and the Antarctic indicate rapid fluctuations of climate which must be related to changes in the polar atmospheres. These interstadials are referred to as Dansgaard–Oeschger events and are given a numbering system with the prefix IS. Their duration was only of the order of a thousand years, and the onset and termination sometimes occurred in a matter of decades. The pattern of cooling and warming during an interstadial–glacial cycle is not symmetrical; instead, cooling occurs gradually and the cycle is completed by rapid warming...

...The steadiness of climate indicated for the present interglacial—the Holocene, from about 10,000 bp to the present, is in marked contrast to the variability of climate indicated for the last glacial and earlier periods...

...The fluctuations are grouped into Bond cycles (Figure 5). In each cycle, there is a gradual decrease in amplitude of the variations as well as a decrease in the temperature of the base level. Near the end of each cycle (that is, at the coldest part), the nature of the ocean-floor detritus indicates the occurrence of a Heinrich event, ascribed to a massive discharge of icebergs into the North Atlantic...

...Two leading theories have emerged to explain the observed sub-Milankovitch climatic excursions: one proposes catastrophic collapse of large Northern Hemisphere ice sheets caused by internal feedbacks and basal instability (termed binge–purge cycles), while the other argues that the global synchrony of the rapid shifts requires an atmospheric mechanism, probably relating to a water vapor feedback process..."

:blink:

So, TheThorn, I come before you with cap in hand, and say "I must have been wrong; I concede those points"

:mellow:

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I still think we need to do more research. And I don't buy "facts" and "info" I get off Wiki as supporting arguments. When it comes to something so scientific and controversial, I'll want real data from researchers. I love Wiki, don't get me wrong, but I don't trust it here. The facts in the article might even be correct, but there's no guaruntee there aren't omissions. For this argument, I'll stick to peer-reviewed print.

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~ cogito cogito ergo cogito sum ~

Nothing in life is good nor bad; thinking makes it so.

Agreed. And 'peer-reviewed' is a good filter...but I would offer this as a consideration:

Even the most thoroughly researched reports have to be synthesised down from massive amounts of data (previous work, experimental results and analyses, background research, conceptual research, etc) - there is a risk of (potentially important) omissions...
The collective body of evidence (which does include 'oral histories' or 'folk wisdom', as well as 'real-time' measurements, ice and sediment cores, the geological record...- or, more precisely, the consensual interpretation thereof) does indicate that average temperatures are rising...
Whether the current rise is part of a 'short cycle', 'medium cycle', 'long cycle', 'super cycle', or unprecedented...remains unanswered to my satisfaction <_<
So, yes...more research...more facts and analyses...more...more!

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Ice Shelf Disintegration
Ice Shelf Disintegration Threatens Environment, Queen's Study
'The spectacular disintegration of Antarctica's "Larsen-B" Ice Shelf was unprecedented since the last ice age, according to a recent study published in Nature. And the disintegrating Antarctic ice could have huge implications for global warming and rising sea levels.' from ScienceDaily.com

"more fuel for the fire...?" :mellow:

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Carbon Dioxide Emissions
Faster Carbon Dioxide Emissions Will Overwhelm Capacity Of Land And Ocean To Absorb Carbon
"It's all about rates. If the rate of fossil fuel emissions is too high, the carbon storage capacity of the land and oceans decreases and climate warming accelerates."
from terradaily.com (via spacedaily.com)

"yet more fuel...?" :mellow:

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* Siberia's rapid thaw causes alarm *
The world's largest frozen peat bog is melting, which could speed the rate of global warming, New Scientist reports.
Full story:
here

more fuel for the fire? or 'alarmist' tripe? <_<

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Errors In The Measurement Of Global Warming Corrected

New Haven CT (SPX) Aug 12, 2005
The effect of the sun's heat on weather balloons largely accounts for a data discrepancy that has long contributed to a dispute over the existence of global warming, according to a report by scientists at Yale University and the National Oceanic and Atmospheric Administration (NOAA).
Full story

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I guess I have to put in my two-bits into this discussion. The "IceAge" 0r Pleistocene Epoch could just as well be called the "Volcanoe Age" as it was a time of worldwide volcanism. This was not so much a cold period, but a very wet period, possibly caused by volcanic emissions. Very large lakes formed in many parts of the world. Lake Bonneville in Utah was a gigantic lake where the Great Salt Lake is a mere remnant. The accumulation of ice during the "Ice Age" resulted from the great increase in precipitation at higher elevations and higher latitudes. With the wanning of precipitation, the ice began its retreat (melting back). As more and more areas of land and sea became ice free, the solar reflection decreased and the rate of melting accelerated. Witout another periood of worldwide volcanism, the earth will continue to recover from the Ice Age, having a warmer climate and a higher sea level as existed in the Pliocene Epoch which preceded the Pleistocene.
Jack

JESMKS, it's true that widespread vulcanism can lead, and has led, to global cooling - it doesn't always lead directly into an Ice Age, but it does lead to increased precipitation in mid-latitudes... in particular the global low rainfall belts which today are deserts. Lake Bonneville is a good example; in Australia at that time there was also a mildly saline extensive lake called Lake Dieri in some reports (its remnant is Lake Eyre), and the Sahel and Sahara were woodlands and high grass prairies with quite a few sizable rivers and lakes.

Both the K/T (Cretaceous/Tertiary ~65MA BP) and the P/T (Permian/Triassic ~225MA BP) transitions were marked by extensive vulcanism (and major boloidal impacts) but no major Ice Ages.

The Pleistocene vulcanism was fairly mild in comparison. <_<

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