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Arctic Ice melts more

by whataboutbob Sat Oct 1st, 2005 at 05:24:22 PM EST

From the BBC World News: Arctic Ice "Disappearing Quickly"

The area covered by sea ice in the Arctic has shrunk for a fourth consecutive year, according to new data released by US scientists.
They say that this month sees the lowest extent of ice cover for more than a century.(...)

"It's still a controversial issue, and there's always going to be some uncertainty because the climate system does have a lot of natural variability, especially in the Arctic," says Mark Serreze, of the National Snow and Ice Data Center (NSIDC), Boulder, Colorado.

"But I think the evidence is growing very, very strong that part of what we're seeing now is the increased greenhouse effect. If you asked me, I'd bet the mortgage that that's just what's happening."

We aren't sure what it all means...but here is some information to chew on:

"What we're seeing is a process in which we start to lose ice cover during the summer," he said, "so areas which formerly had ice are now open water, which is dark.

"These dark areas absorb a lot of the Sun's energy, much more than the ice; and what happens then is that the oceans start to warm up, and it becomes very difficult for ice to form during the following autumn and winter.

"It looks like this is exactly what we're seeing - a positive feedback effect, a 'tipping-point'."

The idea behind tipping-points is that at some stage the rate of global warming would accelerate, as rising temperatures break down natural restraints or trigger environmental changes which release further amounts of greenhouse gases.

Possible tipping-points include
-the disappearance of sea ice leading to greater absorption of solar radiation
-a switch from forests being net absorbers of carbon dioxide to net producers
-melting permafrost, releasing trapped methane

tipping points...sounds ominous...can anyone out there say more about this?

Display:
Arctic Ice melts more | 47 comments (47 topical, 0 editorial, 0 hidden)
Re: Arctic Ice melts more (none / 0)
I don't have a reference for this, but I recall recently seen a report that some temperate forests in Europe were becoming net producers of carbon during the summer due to higher temperatures.

The story of permafrost melting in Siberia and Alaska has been all over the press during the last month (here is the top google news hit as I write).

So we might be seeing all three tipping points taking place.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Thu Sep 29th, 2005 at 11:49:38 AM EST
I sorta get the same feeling... (none / 0)
these events are following each other too quickly. And no one really even knows about them unless you read something like Eurotrib or are connected with some sort of a green organization. US government officials still deny any changes.

And once it tips, change will be neither subtle, nor slow.

by gradinski chai on Thu Sep 29th, 2005 at 12:57:03 PM EST
[ Parent ]
Re: Arctic Ice melts more (none / 0)
I don't have a reference for this, but I recall recently seen a report that some temperate forests in Europe were becoming net producers of carbon during the summer due to higher temperatures.

Could this be what you saw?

It's quite scary, anyway...

You have a normal feeling for a moment, then it passes. --More--

by tzt (tzt) on Thu Sep 29th, 2005 at 07:02:02 PM EST
[ Parent ]
Uhm... (none / 0)
Here's your daily critic again... I do this all the time on this board when newsflashes like these show up.

Thanks for the link, BTW.

How can I tell you in a kind way that the Environment Correspondent in this piece is another example of a phenomenon Colman had a diary on: Bad Science Reporting. This is a prime example of someone not doing his homework. Mr. Black, go wash your head in tomato sauce and go paint the town red afterwards.

Plants do no switch from the adsorbtion to the production of CO2 because of temperature. That's a children's tale to keep it simple.

Here's my children's tale.

We start with the familiar part: Plants use carbon during photosynthesis and produce oxygen during the day. However, that's just half the story: during the night, they use oxygen and produce... CO2. Since we have a 1:1 distribution of day and night in one year, the net loss or gain of atmospheric CO2 is exactly zero. So, please laugh when people start crying about "preserving the lungs of the earth". It's rubbish. (We should keep them because they're beautiful and unique and all that, but for carbon loss it doesn't matter a fig on a stick.)

Now for the second part. When plants grow, they use carbon and this makes plants a carbon sink. Cudos to the reported to have that right. Unfortunately, plants die. When they die, they get broken down by bacterial processes and your stored carbon is back in the atmosphere having a party with the other carbons.

So, the actual story of 2003 looks like this: Because of the heat, plants grew slower while an usual (or presumably slightly larger) amount of plants gave up and died. This leaves you with a large source and a reduced sink and we have a whopper of a CO2 increase.

Fortunately for us human beings, there are enough cold spells during a decade to wipe these freak spikes away again. If you worry about continuous increase of temperature with time and the spikes no longer disappear, I present to you: the ocean. It's huge. It contains huge squids, too. It is also a huge CO2 reservoir.

Now, this is the part where I should do my homework again, so this is up for debate: I thought to remember that the solubility of CO2 in water increases, so that the ocean can store more CO2. Unfortunately, it takes a while to warm the ocean up to see effects, so in the mean time, humanity drowns, the ocean wins and all was tranquil again. The end.

Thank you, thank you, thank you. I will now hit the bunk.

by Nomad (Bjinse) on Thu Sep 29th, 2005 at 10:01:46 PM EST
[ Parent ]
Re: Uhm... (none / 0)
Nomad, It's actually nice to have a scientist (or at least someone who has knowledge in this area) here, to reality check our science bits. I reported this because I sense it is important...but I don't know what to make of the melting, or as regards to "tipping points", which sounds ominous, but on which I have no idea what that means exactly. Have any information on this?

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia
by whataboutbob on Fri Sep 30th, 2005 at 03:28:12 AM EST
[ Parent ]
Re: Uhm... (none / 0)
The idea is that systems can radically change their subsequent behaviour when only a small change is made to initial conditions. If you take one of those coffee "bowls" that people drink their morning coffee from, place if on your table and tip it idley to one side there is a precise angle before which the cup falls back to the table and all is well. However if you go past that angle the cup falls on its side, the coffee spills everywhere and your morning is ruined.

The theory is that the climatic system acts in the same way and that there are small increments in (say) CO2 or temperature that will have massive changes in subsequent climatic behaviour such as rapidly accelerating warming or sudden cooling.

I'd rather not carry out the experiment to confirm the theory.

by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 03:54:57 AM EST
[ Parent ]
Re: Uhm... (none / 0)
You could also think of it as a life event which, while seeming minor to an outside observer, is sufficient to cause a major crisis in someone with mental health problems. The straw that broke the camel's back.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 04:03:04 AM EST
[ Parent ]
Re: Uhm... (none / 0)
To expand even further, since I have now drunk the above bowl of coffee, one of the possible cases is oceanic methyl hydrates. These are deposits of methane compounds on the sea floor that are pretty unstable. It's possible that a small change in  ocean temperature could cause them to boil off into the atmosphere, rapidly increasing the greenhouse effect and leading to much faster warming. This wouldn't be a good thing.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 04:15:15 AM EST
[ Parent ]
Re: Uhm... (none / 0)
Okay, we are lucky to have TWO scientists commenting here...

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia
by whataboutbob on Fri Sep 30th, 2005 at 07:01:34 AM EST
[ Parent ]
Re: Uhm... (none / 0)
(We should keep them because they're beautiful and unique and all that, but for carbon loss it doesn't matter a fig on a stick.)

Not precisely true: if we destroy forests they decay and release CO2. If they're not replanted there will be a rise in CO2. The net change in the amount of plant matter has an effect.

If you worry about continuous increase of temperature with time and the spikes no longer disappear, I present to you: the ocean. It's huge. It contains huge squids, too. It is also a huge CO2 reservoir.

While the supply of huge squids is great for my calamari consumption habits, I'm not sure that we can rely on the ocean to act as a sponge for our CO2. Why hasn't it absorbed the increases over the last century? I've also seen suggestions that a warmer ocean may not absorb CO2. I don't think we understand the ocean systems well enough to be very sure what it will do.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 04:00:18 AM EST
[ Parent ]
Re: Uhm... (none / 0)
Your first point, correct. But I referred to the carbon cycle by photosynthesis, and you used my second point of carbon sinks against me. Well done, but it does leave people completely flabbergasted if you tell them that cutting down jungle isn't bad if you keep up reforestation. Cynical, but true.


Why hasn't it absorbed the increases over the last century? I've also seen suggestions that a warmer ocean may not absorb CO2.

Again, good point. Actually, you made me wonder whether such simple chemical experiments have been done: Examine the dissolved CO2 for oceanic water at steady CO2 pressures with increasing temperatures.

I can answer you why I think it hasn't absorbed the increased CO2 of the last century: because it isn't warm enough yet. These things correct themselves, but it takes a while. For a greater CO2 capacity, the oceans first needs to be warm. There have been estimates and most point out that this is a slow process and that the oceans won´t follow global warming as the atmosphere does. Once it happens, though, atmospheric CO2 is reduced gradually as it becomes spread out over the oceans. The trick I left out in the last post was the formation of limestone. For oceanic water, the solublity of limestone (CaCO3)-decreases- with temperature, so precipitation is enhanced, generating a larger carbon sink.

In an aside, have you perhaps heard of the concept of Gaia, introduced by James Lovelock?

But all of the above could be rubbish, too. Your final remark is the most true of all and underpins all attempts to model climate change.

by Nomad (Bjinse) on Fri Sep 30th, 2005 at 06:46:12 AM EST
[ Parent ]
Gaia (none / 0)
I have heard of Gaia, which is that the earth is a living conscious being, which we are just cells in her body...right? (If wrong, coorect me, please). I am curious/interested, what are you thinking of, when you mention Gaia here?

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia
by whataboutbob on Fri Sep 30th, 2005 at 07:04:55 AM EST
[ Parent ]
Re: Gaia (none / 0)
Not precisely: Lovelock is rather less romantic than that. He sees the earth as a single organism capable of self-correcting imbalances - healing. He doesn't attribute sentience or mystical power to the system. In the introduction  The Ages of Gaia he's very clear that Gaia is  metaphor in order to help communicate.

In fact, in the preface to Gaia: A New Look at Life on Earth he syas:

I have frequently use the word Gaia as a shorthand for the hypothesis itselt, name that the biosphere is a self-regulating entity with the capacity to keep our planet healthy by controlling the physical and chemical environment. Occasionally it has been difficult , without excessive cirumlocution, to avoid talking of Gaia as if she were known to be sentient. This is meant no more seriously that is the appellation "she" when given to a sheop by those who sail on her ....

The self-correcting bit is maybe slightly misleading: life created the Earth into what it is today, from the nature of the land and sea to the gases in the atmosphere. And a healthy Earth does not have to be a nice place for humans.  

by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 07:27:10 AM EST
[ Parent ]
Almost... (none / 0)
... I think Lovelock defined it as self-regulating system similar to a living cell; in that analogue, though, the earth would be the cell and humans would be, say, proteins. Or, if you're really getting cynical about how men butch things up as a species, prions would describe us better.

Some people have taken to interpret the Gaia theory as how you described it, although I can't really agree by that definition. Consciousness possesses the ability to reflect; the earth as a whole doesn't do that. Life tinkers aways, but it does in such a way that it maintains the conditions which favour organic life. And that's the Gaia theory in a nutshell.

I mentioned Gaia because it is such a good example of the check-and-balances the earth has built in to keep a certain state of equilibirium. This discussion about CO2 underlines that concept. I'll merge further information about the Gaia theory in the post I'm preparing as response to your question above.

by Nomad (Bjinse) on Fri Sep 30th, 2005 at 07:51:01 AM EST
[ Parent ]
Re: Almost... (none / 0)
I'll take exception to "check-and-balances the earth has built in". The earth tends to stay in its current state of equilbrium because the natural forces that made it still act. Disturb it enough though and they won't act in the same way. The checks-and-balances aren't built-in. They're the forces that brought us to the equilibrium.

Equilibrium isn't a good term either, given the way that the earth changes over only tens of thousands of years.

by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 07:54:58 AM EST
[ Parent ]
Not completely true, I think (none / 0)
BTW, tens of thousands years is fast enough for a geologist to still refer to it as equilibirium. Time is bunk, that sort of thing. I agree that the nomenclature is not perfect.

Most of what you say is the interpretation of how we should envision the "maintenance" processes of the earth. I won't step into that further, I'm not well read on that terrain.

One extra note though: Intentionally or not, you make it sound as if the checks-and-balances are static processes with time. They're not; they're dynamic: The forces that brought us to current equilibrium are not equal to the amount of "maintenance" forces that are currently present on the earth. One of the finest examples I know by head is the development of phytoplankton influencing cloud formation, affecting the earth's thermostat. The conditions wherein phytoplankton could evolve were created by previous processes. After the appearance of phytoplankton, the earth suddenly had gained yet another mechanism to regulate climate. The new ones got "discovered" and implemented as the earth went along doing its business.

by Nomad (Bjinse) on Fri Sep 30th, 2005 at 10:42:28 AM EST
[ Parent ]
Re: Not completely true, I think (none / 0)
One extra note though: Intentionally or not, you make it sound as if the checks-and-balances are static processes with time.

Well that says lots for my writing skills since that was the exact opposite of what I intended to say. The phytoplankton example was actually in my head as I wrote.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 10:57:16 AM EST
[ Parent ]
Re: Not completely true, I think (none / 0)
BTW, tens of thousands years is fast enough for a geologist to still refer to it as equilibirium.

True, but I'm not a rock. Over geological time you're correct but not over the lifetime of our species or society.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 11:01:35 AM EST
[ Parent ]
Re: Not completely true, I think (none / 0)
Though at this stage on a Friday I may in fact have the IQ of a rock.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 11:02:07 AM EST
[ Parent ]
Re: Uhm... (none / 0)
I saw information on some experiments that had been done recently that gave me the impression that we can't rely on the oceans as sinks: damned if I can remember the reference. There are effects from the effects of warming on ocean life as well, some good, some bad.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 07:29:06 AM EST
[ Parent ]
Re: Uhm... (none / 0)
And a biologist friend made an offhand comment that rather floored me at the time, which is that the conditions we are seeing around the world now, are from the effects of what we did 20 years ago. Which suggests, we REALLY have to change now, for we will see a worstening before we see any improvement.

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia
by whataboutbob on Fri Sep 30th, 2005 at 08:10:40 AM EST
[ Parent ]
CO2 + H2O = (none / 0)
OK, now I really don't remember much about high school chemistry, but doesn't the addition of CO2 screw up the PH of water? So it would slowly turn the water more acidic? Right? And if it does that then it could begin to become uncomfortable for little planktons to live...and in one way or another feed us all.

So the ocean as carbon sink may not be such a great idea.

But then again, my high school chemistry may be amiss.

by gradinski chai on Fri Sep 30th, 2005 at 10:06:37 AM EST
[ Parent ]
Re: CO2 + H2O = (none / 1)
Ocean acidification has already been detected and is of concern.

See the Royal Society's paper:  "Ocean Acidification due to Increasing Atmospheric Carbon Dioxide."

http://www.royalsoc.ac.uk/document.asp?tip=0&id=3249

Also--and I don't have the links just now--studies have been done in the Nevada desert (Desert Research Institute) and in a meadow in the Rocky Mountains in which plots of land are subjected to increased CO2.  After a certain threshold, the land (vegetation and bacteria) starts exhaling carbon all the time.

If the oceans acidify rapidly, the results could be catastrophic to all life, starting with any life with a calcium carbonate exoskeleton.

As for James Lovelock, check out:

http://www.ecolo.org/media/articles/articles.in.english/love-indep-24-05-04.htm

by Plan9 on Fri Sep 30th, 2005 at 01:30:29 PM EST
[ Parent ]
Ultimately, ocean is not a good sink (none / 0)
Now we move away from talking about fluxes and start talking about reservoir times.

The best sink/reservoir to reduce CO2 would of course be outer space; that's an irreversible sink. Sinks have shorter or longer time before the captured CO2 gets back into the CO2 cycle. The duration of that time is expressed by the reservoir time: the time CO2 is trapped and locked away from the CO2 cycle.

Sinking off massive amounts of CO2 to the ocean's floor has been suggested as a sequestering of CO2. A few critical questions are here: does that affect the carbon pump of the oceans, how long does it take the oceans to realise they are now containing more dissolved CO2 than they can handle and how fast will the surplus be returned back to the atmosphere? The time dependency is critical in this one. In the end, though, we will still end up with increased atmospheric CO2. That is, if other processes don't get a hold first.

In contrast, the formation of carbonate limestone (CaCO3) is a truly effective, long-term sink for CO2. It's already huge, too. Estimates suggest that a whopping 100.000.000 Gigatonnes of CO2 is currently stored in sediments. Those white cliffs of Dover? Massive segregation of CO2 into limestone, believed to result in a slow temperature decrease across the Cretaceous period. Now that they're exposed to the atmosphere and slowly get weathered away by geologists hacking them to bits to find fossils (and the rain helps too), limestone would slowly convert back into atmospheric CO2. Consider: that's more than 70 million years of CO2 removed from the atmosphere. Partly because of that missing CO2, we now have glacial periods.

by Nomad (Bjinse) on Fri Sep 30th, 2005 at 11:48:23 AM EST
[ Parent ]
Re: Uhm... (none / 0)
How about phytoplankton dying because of higher water temperatures so that the ocean as an ecosystem loses a lot of its ability to capture CO2?

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman
by Carrie (migeru at eurotrib dot com) on Fri Sep 30th, 2005 at 10:17:50 AM EST
[ Parent ]
The sceptical in me... (none / 0)
...says: wait for next year. Don't jump on events, look for trends. It is worthy to note, of course, but people are jumping the gun again. This is the same thing as the freak CO2 spike seen in Europe by that sweltering summer, mentioned above.
by Nomad (Bjinse) on Fri Sep 30th, 2005 at 10:56:29 AM EST
[ Parent ]
Re: The sceptical in me... (none / 0)
I do not advocate alarmism, but there are too many weird things going on, all at one. Arctic ice, permafrost, glaciers, temperate forests, floods, droughts, tropical cyclones...

While weather is a real phenomenon, climate is a statistical concept. Therefore climate change cannot be attributed to any single event, or even to any small collection of events. However, all of these "signs" are the kinds of effects that climate scientists have predicted for a while that would happen/get more extreme as the earth.

I don't take these events as indications of climate change, but as a taster of what is in store for the next few decades if climate scientists are right in their predictions. Let's just hope that they are not right about the thermohaline circulation stopping overnight, because it that happens we're FUBAR, and it only needs to happen once (i.e., the THC is either there or not: it's not statistical).

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Sep 30th, 2005 at 01:15:17 PM EST
[ Parent ]
It may surprise you... (4.00 / 2)
... but I completely agree in what you say. You can go explaining all these separate observations in a different way, but taken all together, it is hard to escape the notion of an alarming trend. I'm pretty much convinced we're experiencing the tell-tale signs of global warming. I'm far less convinced how much of it can -really- be contributed to CO2 exhaust. Even so, I can not fathom that the exponential surge in released CO2 during the 20th century should pass without any consequences (either now or later in the future) and I favour any program that aspires to CO2 reduction. It simply would be prudent to act on it.

Nevertheless that doesn't halt me to remain critical and caution to consider the other view. It is very hard these days to find a report on a phenomenon that doesn't get instantly linked to global warming; it is almost tunnel vision and I find that bad behaviour in any circumstance. And as I have commented before in another thread, the issue has become severely politicised, hence polarised. That doesn't really help.

by Nomad (Bjinse) on Fri Sep 30th, 2005 at 02:06:15 PM EST
[ Parent ]
Re: It may surprise you... (none / 0)
For the sake of argument, which I think is important, based on your comment here (to have some sense of objectivity)...I would be keen to hear another model or possibility, than the global warming model. What else could be going on?

A diary of its own, maybe?

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia

by whataboutbob on Fri Sep 30th, 2005 at 05:43:24 PM EST
[ Parent ]
An alternative theory (none / 0)
Part of the problem with interpreting long term trends is that the old data isn't very good. For example, tide records have been accurate for hundreds of years, because it was important to know when to sail your ship. Old temperatures are poorly known, because they were hard to measure and didn't really matter.

Here's an interesting hurricane history chart from the National Hurricane Center. Bars depict number of named systems (open/yellow), hurricanes (hatched/green), and category 3 or greater (solid/red), 1886-2004.

Is there a trend? Or is the apparent trend on the right side of the chart the result of the changes in the way things were recorded after 1944 when aircraft became available for remote observation?

An alternative theory: The sun has a cycle that is currently making the earth warmer, as discussed here:
http://en.wikipedia.org/wiki/Image:Solar_Activity_Proxies.png

See any relationshipb between the two charts? (Yes.)It's a VERY complicated problem.

by asdf on Fri Sep 30th, 2005 at 11:13:40 PM EST
[ Parent ]
Another source (none / 0)
"Increased output from the Sun might be to blame for 10 to 30 percent of global warming that has been measured in the past 20 years, according to a new report published online this week by the journal Geophysical Research Letters. Increased emissions of carbon dioxide and other heat-trapping gases still play a role, according to Nicola Scafetta and Bruce West of Duke University."
http://www.livescience.com/environment/050930_sun_effect.html

Full article at
http://www.agu.org/pubs/current/gl/?month=September

by asdf on Fri Sep 30th, 2005 at 11:23:42 PM EST
[ Parent ]
Words from my mouth (none / 0)
asdf, thank you. Those were near to exactly the points I was going to make. The word should get out about statistics every day: "There are lies, damn lies and then there are statistics" (quoted from Benjamin Disraeli). There's nothing, [b]nothing[/b] in this world that can be manipulated in this world with such an ease as statistics.

Again, I consider it inevitably that there will be a repercussion for what we are doing with liberated CO2. However, there are 2 argument that are still gravely overlooked and I want to list them out here briefly. One, the time dependency of enhanced CO2: how long does it take before we receive feedback from increased CO2 levels? 100 years? 1000 years? 5 years? There's no accurate way to model that, since we don't understand every aspect of the climate system.

Secondly, and this is where the links from asdf blend in, if we are indeed experiencing the first effects of CO2 warming, how severe is its effect? Most of the writers of this board will have heard of the Medieval Warm Period we had here in Europe. That has been pretty much established on scientific grounds and proxy data and such. There is still debate whether it was regional (which strikes me, personally, as odd, but I'm not that much of a climate expert to know) or global. Instinctively, I feel that it doesn't make much sense to have just one part of the world experience more warmth than others, though. Even so, there isn't much known HOW it became suddenly warmer for a couple of 100 years and then slacked off again.

Personally, as someone slightly familiar with cyclicity and paleostratigraphy, I suspect that beside the well established Milankovitch cycles there are smaller, slighter cycles within the earth's system that also have an impact on its climate. But in combination with statistical error, fault propagation in sampling and other small-scale effects (such as variation in solar output), the signal gets overshadowed by the fault range. I want to stress: Do not take this as a serious scientific theory; there are my personal suspicions for which I have no scientific grounds whatsoever.

And finally, sampling technique. We have entered the computer age and with the rise of satellite, climate modelling really came in the lift. But as the graph from adsf points out, that makes data comparison extremely tricky. There's a great risk an advanced technique tracks trends that were not recognised by the old "sampling" technique. In science, it's Bad Stuff, if you start comparing a same process, but based on different sampling techniques and draw conclusions from that. Then the method is flawed.

by Nomad (Bjinse) on Sun Oct 2nd, 2005 at 10:09:32 AM EST
[ Parent ]
Botched link... (none / 0)
afew has been teaching me html, so I'm taking my first steps, but I probably keel over quite a few times...

Try again:
Milankovitch cycles

by Nomad (Bjinse) on Sun Oct 2nd, 2005 at 04:11:56 PM EST
[ Parent ]
Re: Botched link... (none / 0)
You've got it.
by afew (afew(a in a circle)eurotrib_dot_com) on Mon Oct 3rd, 2005 at 01:20:20 AM EST
[ Parent ]
Medieval Warming (none / 0)
There was an affect here in New Mexico as well.  I would have to do some research to find sources but the rainfall during the time the Chaco Canyon culture developed was sufficently higher to allow agriculture to support a much larger population than can live there now.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre
by ATinNM on Mon Oct 3rd, 2005 at 02:08:08 AM EST
[ Parent ]
Re: Uhm... (none / 0)
That was the study I saw. Thanks.
by Colman (colman at eurotrib.com) on Fri Sep 30th, 2005 at 10:58:08 AM EST
[ Parent ]
Re: Arctic Ice melts more (none / 0)
I heard this programme tonight do hear it.


Arctic Ice Melt

The latest news that the Arctic ice is shrinking for the fourth year in a row may be just the tip of the iceberg.

A new satellite, Cryosat, due to be launched next month, will provide vital data about the mass of the Arctic ice and the likely future of British weather.

by PeWi on Thu Sep 29th, 2005 at 07:36:48 PM EST
Re: Arctic Ice melts more (none / 0)
In a Melting Trend, Less Arctic Ice to Go Around


by Fran on Fri Sep 30th, 2005 at 01:46:17 AM EST
[ Parent ]
Re: Arctic Ice melts more (none / 0)
On a related topic, more good news:

"Global warming could threaten ocean life"

http://www.swissinfo.org/sen/swissinfo.html?siteSect=106&sid=6126393&cKey=1128065607000

(From a Swiss scientific team). Ugh...lots of scary environmental news lately...when will we all start getting REAL scared and do something about it, is the question?

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia

by whataboutbob on Fri Sep 30th, 2005 at 10:11:25 AM EST
Re: Arctic Ice melts more (none / 1)
quick answer:  when rich white people start going hungry and/or dying.  not until then.

The difference between theory and practise in practise ...
by DeAnander (de_at_daclarke_dot_org) on Fri Sep 30th, 2005 at 05:49:47 PM EST
[ Parent ]
Again... (none / 0)
Cynical, but true.
by Nomad (Bjinse) on Fri Sep 30th, 2005 at 10:32:37 PM EST
[ Parent ]
Re: Arctic Ice melts more (none / 0)
Well, as of today the Swiss pay an additional 1.5 Rappen or 1 cent (Euro) climat tax on the gas, despite high gas prizes. The goal is to reduce CO2-emission.

Sorry no English source yet -  Klimarappen verteuert Liter Benzin um 1,5 Rappen - Ab heute sind Benzin und Diesel für die Autofahrer noch etwas teurer: Mit einer Abgabe von 1,5 Rappen pro Liter wollen der Bund und die Stiftung Klimarappen den CO2-Ausstoss senken.

by Fran on Sat Oct 1st, 2005 at 03:19:21 AM EST
[ Parent ]
On a somewhat related topic (none / 0)

But, according to a researcher at the Climate Mission at the Caisse des Depots, a French state-owned bank, farm animals must also shoulder some of the blame.

France's 20 million cows account for an astonishing 6.5 percent of national greenhouse-gas emissions, according to his estimates.

Each year, their belches send 26 million tonnes of these gases into the atmosphere.

Their faeces -- "dejection bovine," to use the poetic-sounding French phrase -- account for another 12 million tonnes.

Compare that with the 12 million tonnes of gas emitted by French oil refineries, demonised by greenies as climate-killers.

Nor is bovine gas just any old gas.

It comprises methane and nitrous oxide, which volume-for-volume are 21 and 310 times more effective at trapping solar heat respectively than boring CO2.

By itself, methane is to blame for a fifth of the man-made greenhouse effect of the past 200 years.

The good news is that, when it comes to cow farting, we can all breathe a little easier.

"Bovine flatulence plays a negligible role in global warming," is the prim assessment of researcher Benoit Leguet.

His work seems offbeat, but its purpose is serious -- to pinpoint major sources of greenhouse gas that have escaped notice simply because climatology is such a young science.



In the long run, we're all dead. John Maynard Keynes
by Jerome a Paris (etg@eurotrib.com) on Sun Oct 2nd, 2005 at 11:49:22 AM EST
Found something else... (none / 0)
This is a different topic in itself, but somewhat related... Jerome's post indicated other sources of greenhouse gasses beside fossil fuel CO2, which is interesting in itself. Could we actually list out how many CO2 sources there are which could chip in? Hell of a job. Another thought: Humans are, by definition, large CO2 producers. Where are those statistics on global population growth?? (If you're really getting cynical, you could suggest that a pandemic would be good to CO2 reduction...)

A post of asdf above points other climate forcing factors. I found this website the other day, in response to a question I had asked myself: have simple thermodynamical tests been done on ocean sea water and different CO2 pressures? The implication of this test is fascinating: it suggests that the warming of the earth triggers release of the ocean's carbon dioxide (without biosphere). A global warming would therefore result in higher CO2 in the atmosphere. If you combine that with what the time dependency of climate response, you can ask: what comes first? Does global warming boosts atmospheric CO2 or does atmospheric CO2 results in global warming? Chicken or Egg question.

The downside: if CO2 has a large forcing on global warming as some scientists argue, it will ultimately result in CO2 release from the oceans, further enhancing atmospheric CO2. You get a run-away process that way.

by Nomad (Bjinse) on Sun Oct 2nd, 2005 at 01:30:02 PM EST
[ Parent ]
Tipping Point (none / 0)
In a chaotic system there are two measures used to denote the dynamics.  One is the Lyapunov Exponent (LE) which can be either:

Positive = Loss of Information, increase in entrophy
Negative = Increase in Information, decrease in entrophy
Zero = 'It just sits there', no increase or decrease

representing attraction to a point or, more likely, some number of points.

Then there is the Kolmogrov-Sinai (KS) measure of "memory" of the system.  This one is slightly more tricky to explain briefly but it can be thought of as the amount of repelling from the attractor - 'stickiness,' as it were.  

Together the LE and KS describe non-linear systems (NLS) in such a way we can make the equation:  

NLS = LE + KS

A "tipping point" is when the attraction (LE) to a different state is greater than the 'stickiness' (KS) can withstand and the system jumps to a different equilibrium, XOR goes skipping through several different reachable states until reaching equilibrium, XOR goes completely crazy and never reaches a new equilibrium.  

(The last is extremely rare in real, non-trival, systems and I wouldn't worry about climate achieving that state.)

Once a tipping point is reached nothing can stop the system, driven by its own internal dynamics, from achieving a another equilibrium.  Superficially, it seems possible to shovel in additional inputs, if one knew what they were, but the theory says we can't know as Sensitivity Dependence to Initial Conditions tells us we can't predict where the system is going so we cannot ascertain the affect of any additional input(s).  We can certainly muck it about but whether the result would give us a better or worse result is both unpredictable and unknowable.  

In Theory climatic change can happen in a single iteration.  The Greenland Ice Cores seem to indicate the last Ice Age ended in not less than 10 and not more that 20 years.  Assuming one is a rock :-) that is faster than a speeding bullet. In human terms ... not so much.  But it is certainly quicker than most people are expecting.

   

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Sun Oct 2nd, 2005 at 08:53:24 PM EST
Extremely cool (none / 0)
Do you, perhaps, know a website (or book) where this is explained in further detail but still understandable for chaos theorem rookies?

And yup, if the Greenland ice cores are indeed correctly read, climate change can be radical. Which makes concern about an abrupt break in Warm Gulf Stream the more realistic. Practically, you can expect that within one generation, the climate has drastically changed. Then grandparents would really have nice stories again, "In my day, when I was young, etcetera..."

by Nomad (Bjinse) on Sun Oct 2nd, 2005 at 10:50:05 PM EST
[ Parent ]
Best Book (none / 0)
"Chaos, Making a New Science" by James Gleick is by far the best non-technical introduction I've ever read. Gleick is writing for a general audience but he never talks down and all the important concepts developed up to 1987 are included.

A more technical, but still very accessible, work is Edward Lorenz's (yes, that Lorenz) "The Essence of Chaos."  Lorenz's paper wherein he introduced the Butterfly concept is included as an appendix.

Fundamental is Mandelbrot's "The Fractal Geometry of Nature."  This, with the Lorenz paper, is the ur text.

A truly gnarly work with more math than one person can stand is "Chaos and Fractals: New Frontiers of Science" by Peitgen, Jurgens, and Saupe.  If nothing else you can use a copy to beat people to death; the sucker has to weigh at least 10 pounds (4.54 kilos.)  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Mon Oct 3rd, 2005 at 01:43:18 AM EST
[ Parent ]
Arctic Ice melts more | 47 comments (47 topical, 0 editorial, 0 hidden)


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