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alan
07-06-2014, 12:22 PM
BTW in terms of the big picture it appears that we are hitting the regular repetative point off unstable high temperatures before it falls sharply towards an ice age. The graph of temperature over the last several 100s of thousands of years is very regular in its patterns and we have reached that point. However, the big fall in temperature could be many 1000s of years away yet.

alan
07-06-2014, 07:35 PM
Here is a graph showing the cyclical changes of the earths temperature and how we are approaching the regular plunge into an ice age

http://nebula.wsimg.com/a4e17b75cd6dd3699ab70777c290a1df?AccessKeyId=AD730 7F3D4020EDFF747&disposition=0&alloworigin=1

Basically we are headed close to the regular post-ice age temperature peak and some time in the next while the regular pattern means a sudden plunge in temperature. Soon and sudden is of course relative and noone knows how soon it will be - some say its still 10000 years away but noone is sure.

I also read that there is often a period of wiggly unstable weather just as we fall off the peak towards the plunge.

jdean
07-06-2014, 07:44 PM
Thanks, I needed cheering up : )

Agamemnon
07-06-2014, 07:56 PM
So much for global warming lol

alan
07-06-2014, 08:04 PM
There is a theory that global warming caused by man made Co2 is all that is holding off the natural cyclical plunge into the next ice age

http://www.theregister.co.uk/2012/11/09/peat_ice_age_coming_only_co2_can_save_us/

So I am off to burn some car tyres/tires in the back yard :0)

lgmayka
07-06-2014, 10:46 PM
Chicago could certainly use some warming. 2014 was the coldest winter in Chicago history (http://www.huffingtonpost.com/2014/04/02/chicago-coldest-winter-ever_n_5078201.html). This Chicago winter also ranked 3rd in total snowfall (http://www.crh.noaa.gov/lot/?n=chi_seasonal_snow). (We just missed #2.)

alan
07-07-2014, 12:48 PM
I dont know all the ins and outs of this but although it seems contradictory there is a school of thought that rising earth temperature reaches a peak and then the gulf stream gets messed up as a result of the melting ice and there is a sudden plunge in temperature. You can see the basic repeated pattern of a peak followed by a steep fall on that graph I posted which seems to show that the peak is relatively soon followed by steep fall towards the ice age in what seems to be a very long term repeated natural cycle. So, although a lot of people see the whole idea of crashing towards an ice age a bit contradictory with the peak global temperatures its actually exactly what is the very long term repeated natural cycle.

I have also read that at this point between the peak and the fall there tends to be a period of extremes of weather which is in line with the pattern of hot summers and some very cold winters too.

I must admit I am more convinced than I once was that this is largely a natural cycle with tipping points where warming up releases a lot of the natural carbon until it reaches a peak point where it causes a temperature crash although man does have an effect and its not clear if man's effect is speeding up or slowing down the tipping point.

The isles are especially vulernable to any changes in the gulf stream because our temperatures are kept far more moderate than they should be for our latitude and otherwise we would be more like Canada or Russia. If that happened then it could be a catastrophe because Britain in particular is very densely occupied - only Holland is far more so in Europe - and a crash in its intensive agriculture and a move to Canadian type conditions would quickly lead to mass starvation and migration.

The UK already could barely feed itself with rationing during the blockade in WWII when the population was 40-odd million. Today its more like 65 million. The UK currently would need to be 3.6 times its size to feed its existing population anyway which puts the big lie to the idea it needs to keep mass immigration coming in. What it does have is an aging non-working population problem in common with the rest of the developed world but mass immigration is a very short sighted way of keeping the working population ratio up - kind of like feeding a lion so it doesnt eat you. I am not sure if people in the US are aware of this but the anti-immigration/anti-EU party UKIP (United Kingdom Independence Party) came from nowhere (no MPs) to come in as the biggest party in the recent EU elections held in England. I by no means agree with their general world view - they have lot of real fruitcakes which they keep having to kick out- but they definitely have raised the issue that Political correctness has meant has been off limits to mainstream parties. They took votes off both the right and the left so its not a left-right issue.

mnd
07-07-2014, 02:26 PM
I dont know all the ins and outs of this but although it seems contradictory there is a school of thought that rising earth temperature reaches a peak and then the gulf stream gets messed up as a result of the melting ice and there is a sudden plunge in temperature. You can see the basic repeated pattern of a peak followed by a steep fall on that graph I posted which seems to show that the peak is relatively soon followed by steep fall towards the ice age in what seems to be a very long term repeated natural cycle. So, although a lot of people see the whole idea of crashing towards an ice age a bit contradictory with the peak global temperatures its actually exactly what is the very long term repeated natural cycle.
Where? The IPCC (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-10-2.html) suggests that the Gulf Stream may slow during the 21st century but that a total collapse is unlikely. In any event, even if something like this were to occur, any cooling effect would be localised to the North Atlantic rather than the earth as a whole, and at least a portion of this cooling would be offset by the increased radiative forcing as a result of human emissions.

The problem with extrapolating from the graph you have shown above is that all the previous cycles occurred prior to the Anthropocene. This study (ftp://ftp.soest.hawaii.edu/engels/Stanley/Textbook_update/Science_297/Berger-02.pdf) from Science (which I have heard of, unlike the paper from Mires and Peat which the article you have linked to above references) argues something very different:


Today's comparatively warm climate has been the exception more than the rule during the last 500,000 years or more. If recent warm periods (or interglacials) are a guide, then we may soon slip into another glacial period. But Berger and Loutre argue in their Perspective that with or without human perturbations, the current warm climate may last another 50,000 years. The reason is a minimum in the eccentricity of Earth's orbit around the Sun.

The exact quote is from here (http://www.sciencemag.org/content/297/5585/1287).

A more recent (http://www.nature.com/ngeo/journal/v5/n2/abs/ngeo1358.html) one from Nature reaches the same conclusion regarding impending ice ages when current atmospheric carbon dioxide concentrations are taken into account:


No glacial inception is projected to occur at the current atmospheric CO2 concentrations of 390 ppmv (ref. 1). Indeed, model experiments suggest that in the current orbital configuration—which is characterized by a weak minimum in summer insolation—glacial inception would require CO2 concentrations below preindustrial levels of 280 ppmv (refs 2, 3, 4). However, the precise CO2 threshold4, 5, 6 as well as the timing of the hypothetical next glaciation7 remain unclear. Past interglacials can be used to draw analogies with the present, provided their duration is known. Here we propose that the minimum age of a glacial inception is constrained by the onset of bipolar-seesaw climate variability, which requires ice-sheets large enough to produce iceberg discharges that disrupt the ocean circulation. We identify the bipolar seesaw in ice-core and North Atlantic marine records by the appearance of a distinct phasing of interhemispheric climate and hydrographic changes and ice-rafted debris. The glacial inception during Marine Isotope sub-Stage 19c, a close analogue for the present interglacial, occurred near the summer insolation minimum, suggesting that the interglacial was not prolonged by subdued radiative forcing7. Assuming that ice growth mainly responds to insolation and CO2 forcing, this analogy suggests that the end of the current interglacial would occur within the next 1500 years, if atmospheric CO2 concentrations did not exceed 2405 ppmv.

The first study is referenced by the NOAA here (http://www.ncdc.noaa.gov/paleo/milankovitch.html), under the last paragraph. I don’t think the theory that we’re on the cusp of a new ice age has any mainstream scientific credibility.

Zavod34
11-04-2014, 12:13 AM
Seems rather unlikely.