------ THE SKY IS FALLING ------

[MrBeatnik]

Simple,

Thanks for info.
I have been looking at articles myself, but haven't found anything that I can call relevant to my question, unfortunately - that's why I'm asking here... I thought somebody might already know the info from digging, or at least be alarmed that this info is not provided to give context to the problems we create today.

However you seem to feel that we should currently be in a phase of rapid heating before a more gradual slide into another ice and ask is this normal rate or not.

Indeed... well sort of. The information I have been reading suggests we are still in receding ice age, therefore for it to be receding it must be getting warming to get rid of the ice. Further, the final stages of decline of the ice age can be very sudden and abrupt.

As far as I was aware, we cannot go into another ice age, before the current ice age finishes -- otherwise we are still in this ice age?
It seems you are suggesting that we have just entered an ice age, or at least in the infancy of one:

...temperature trends from natural variations ... tend to indicate that the world was more cooling down than warming up.

So therefore we have contradicting information perhaps.

Were the trends pointing to cooling towards the end or beginning of an ice age cycle? I have no doubt that temperatue can vary over decades for either case (rise or fall).

So really, I am now very confused!

[Paradox]

Hi Mr B,

Originally Posted by MrBeatnik

The question is, was this the normal point in time it should have collapsed?

Probably. It's hard to say with certainty. When I look at the graph (Ice Age temperature changes) which Simple reposted, I see a (natural) trend. Look at the rise then fall pattern of temperature. Unfortunately me saying it's so doesn't mean much.

If there was a quick answer to the question you pose a big area of contention (among scientists) would be eliminated. If you consider the sun and the Maunder Minimum for instance you see a direct correlation to solar output variation and temperature (at least I do). Granted, in the long term I believe there are pronounced natural cycles but variability does exist. Do we consider a Mini Ice Age a variation from the bigger cycle? If we do we must put the Medieval Warm period in the same catagory. Or are they cycles within bigger cycles...within even bigger cycles, with a few cycles thown in just for flavor? The ice core record tells a pretty detailed story about our past.

Are you attempting to ascertain whether or not man is linked to warming? What do you think?

~Paradox

[MrBeatnik]

I think man is linked to warming, however I want to determine the rate of decline that we are causing.

Most of the time, we are told something and expect to accept it.
I like to apply the information to other info, to see how solid that information is!

I had a feeling that there may not be an answer to my question, and I this is a big problem when trying to justify the question of "is man causing global warming".

I'm not trying to argue against not being green, or indeed being green.
I just want to compare "normal" data with our "man made global warming data".
If an answer does exist, it may flip my ideals on what is right and wrong.

Without having the correct info, I am thinking that we are exiting an ice age, which normally has a sharp decline towards the end. So are we really affecting things? I do think so, but maybe not as much as we are led to believe.

[Paradox]

Originally Posted by MrBeatnik

Without having the correct info, I am thinking that we are exiting an ice age, which normally has a sharp decline towards the end. So are we really affecting things? I do think so, but maybe not as much as we are led to believe.

We're on the same page. You are at the right place. I can say from experience that this discussion (and the archive of this thread) addresses all sides of the debate with an impartiality that is hard to find anywhere else. We also try to break news and research pertaining to this topic as it is made available. Like you, I am formulating my opinion and have identified key areas of uncertainty. The data keeps pouring in and I am confident the answers to our questions will be available in due time.

I look forward to your contributions...


~Paradox

[Paradox]

In Ancient Fossils, Seeds of a New Debate on Warming

[Simple]

Without having the correct info, I am thinking that we are exiting an ice age, which normally has a sharp decline towards the end.

Look at the top graph. The ice age cycles have come and gone and about 10-12 thousand years a period of rapid warming ended, the start of the holocene the end of the last ice age. This is the rapid warming you are referring whereas today we are and have been for 10-12000 in an interglacial period not a glacial period to be warming out of.


Since 10,000-12,000 years ago we haven't really changed temperature that much arround the dotted line although we were starting to cool as would be expected from the previous cycles of ice ages.

Since 1800's although particularly since 1970's there has been a rapid warming which is accelerating and associated with unprecedented rates of ice melt as the top article indicates and the current rate of the arctic melt are pointing to. The ice sheets have been shown to melt very rapidly previously in history although probably not this quickly.

So what is happening is that we have entered a rapid warming phase when we should be cooling.

This warming has been preciptated by the release of GHG since the industrial revolution although mainly since 1970 which accounts for the rise in CO2 levels from 300ppm in 1950'ish to 385ppm now. The warming forcing due to CO2 alone has increased from <.5 w/m2 to 1.3-6w/m2 dependent on the source of data.

This is the first time ever from paleoclimatology that GHG have led the way. GHG are normally released after a small warming period induced by the cycles in the earth's tilt etc, and the main role they play is to increase and accelerated the warming effect helped by the rapid loss of albedo as the ice sheets melt.

These GHG's have warmed the earth by 0.6C on average in remote areas away from populations. If the heat from arround cities and towns were included this would be higher. London is approximately 2C hotter than the rest of UK and apparently already has some scorpions in residence.

This rise in temperature has caused some marked melting of ice (99% Glaciers Oct 2006, Loss of ice in arctic very rapid and accelerating antarctica rapdily melting and heating up faster than any other place 1C) and other changes that are causing positive natural feedback mechanisms to release large amounts of extra GHGs. This will further accelerate the warming and will probably cause the arctic to free of summer ice very soon, followed by Greenland.

The last time GHG were so high the temperatures were several degrees higher than today and it seems that where we are heading.

Overall therefore far from saying man has had no effect it seems more correct to say his effect is more than thought. Man hasn't only caused a rapid warming he has managed it when the world was already warm and should now be cooling.

This is the first time in history that warming has been precipitated by GHG and during an interglacial, (Warming is normally out of a glacial period). This is unknown ground and therefore very unpredictable although if the acceleration of warming continues we should reach 1C higher before 2050 and that will be the highest average world temperatures have been for over a million years.

Part of me thinks we need to do something about and now (ZERO GHG) to try to stop the predicted rises of 2-3C as they would melt antarctica and quickly if the arctic is anything to go by. (Antarctica hasn't been free of ice in any of the deglaciations seen in those ice ages on the graphs above.)

[Paradox]

Virtual Globes: NSIDC Data on Google Earth

Experts: Global warming threatens ruins

[MrBeatnik]

Originally Posted by Simple

whereas today we are and have been for 10-12000 in an interglacial period not a glacial period to be warming out of.

The interglacial period is a geological interval of warmer global average temperature. The current situation could also be referred to as interstadial period in the ice age, depending on your view. Either way, the result is a warming. Both terms above can be attributed to natural warming during cycles.

...although we were starting to cool...
The ice sheets have been shown to melt very rapidly previously in history although probably not this quickly.

This confuses me.
Our current warm peak, or end of cycle, may not be over.
It is quite possible that we are near the peak, but timespans are so great that we cannot say we are specifically *should* be getting colder now. In fact, surely it is possible that we can still be getting a little warmer as we haven't hit the highest warmth peak yet. Spans of 100 years can easily show small changes in either direction, regardless of if the Earth is meant to be cooling or heating. We cannot say the last 100 years is evidence compared to a hundred, thousand year timespan.

If ice cycles mean that ice disappears at some point, then we have no ice from the previous (not current) ice age to compare melting rates.
Any ice that we compare today is from the current ice age? Or am I compeltely wrong on this point?

If not, what really confuses me, is how an ice core from Vostok can let us know about the last major ice age (or rather the end of it, where no ice should have existed?).

The ice cores can surely only let us know about the present ice age.
If we were to completely exit this ice age, there would be no ice core left to examine - so there is no evidence of the previous ice age in this manner; there is nothing to compare exact data to.

If we had an ice core from the previous era, would it compare? Perhaps there would be few anomalies.

I thought this was interesting: (Link)

Originally Posted by In Ancient Fossils, Seeds of a New Debate on Warming

In 1992, a team from the University of New Mexico reported that ancient soils showed extremely high levels of carbon dioxide 440 million years ago, an age of primitive sea life before the advent of land plants and animals. The carbon dioxide levels were roughly 16 times higher than today. Surprisingly, the scientists said, this appeared to coincide with wide glaciation.

Considering that emissions have only been examined properly and recorded for the last 100 years or so, this has little effect on the full life of the cycle. We need bigger numbers to look at.

[Paradox]

Originally Posted by MrBeatnik

The ice cores can surely only let us know about the present ice age.
If we were to completely exit this ice age, there would be no ice core left to examine - so there is no evidence of the previous ice age in this manner; there is nothing to compare exact data to.

Mr B,

That depends on how you define an 'Ice Age'. Where do you draw the line? Ice records are limited by time, not necessarily temperature conditions. As the ice grows, past ice thins until it finally disappears. The lower you go in an ice-core the thinner the ice. This is caused by ice flow and has been the greatest challenge in obtaining good data...location - location - location.

You are correct about ice data. There is a limit. Other geological sources are beginning to bridge the gap. You have nailed a key challenge though.

~Paradox

[Simple]

The ice cores can surely only let us know about the present ice age.
If we were to completely exit this ice age, there would be no ice core left to examine - so there is no evidence of the previous ice age in this manner; there is nothing to compare exact data to.

The present ice age began 40 million years ago with the growth of an ice sheet in Antarctica, but intensified during the Pleistocene (starting around 3 million years ago) with the spread of ice sheets in the Northern Hemisphere. Since then, the world has seen cycles of glaciation with ice sheets advancing and retreating on 40,000 and 100,000 year time scales. The last glacial period ended about ten thousand years ago.

http://en.wikipedia.org/wiki/Ice_age

The last ten thoudsand years has been a deglacial period which started with a rapid global warming and true as you say we are still in the 40milion year ice age as we actually have ice.

However the graphs shown are these deglacial periods which follow the trends described, and it seems that from 1000-1700 that the general trend was for a cooling which seems to fit with the slow cooling periods seen in the the previous cycles of deglacials and glacials for the last 40 million years.

It does seem possible however that we are now going to enter a period of being ice free altogether if the warming trends continue.

No link to your quote makes it hard to comment and data from that far back can be wrong by millions of years so need to see the article. From the graphs I've seen carbon dioxide is closely related to temperature until a certain point over about 700ppm after which CO2 doesn't add anymore to warming. It therefore seems possible if other factors (e.g. ash in sky) were causing greater cooling forcings than the warming forcing caused by the CO2 cooling would prevail. Its all a fine balance and the further away from neutral it is the more warm or cool the earth gets and the faster it happens.

At present however the warming forcing from CO2 (380ppm) and other GHG and Black soot, are greater than the cooling forces (sulphur dioxide, low cloud cover) and we are therefore warming.

If CO2 levels were below 300ppm (i.e. without man) the forcing would only be 0.5w/m2 at those levels it is unlikely we would be seeing warming and very likely we would be cooling. The little ice age was a world wide event whereas no one's quite so certain about the medeival warm period. The mini ice age from the trends in graphs started at about the time we would have expected for another heavy glacial period in this ice age to have started.