The coming of another ice-age?
Blog topic:
As they review the bizarre and unpredictable weather pattern of the past several years, a growing number of scientists are beginning to suspect that many seemingly contradictory meteorological fluctuations are actually part of a global climatic upheaval....The trend shows no indication of reversing. Climatological Cassandras are becoming increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age.
Namely, it is not a new phenomenon that people are worried about climate change. Today it is warming, but a few decades ago it was apparently cooling (though obviously not at the same hysteria levels of today). We can also see other parallels. For example, the arctic currently supplies evidence for global warming, but back in the 70's, it supplied clear evidence for cooling:
When Climatologists....analyzed satellite weather data for the Northern Hemisphere, they found that the area of the ice and snow cover had suddenly increased by 12% in 1971 and the increase has persisted ever since. Areas of Baffin Island in the Canadian Arctic, for example, were once totally free of any snow in summer; now they are covered year round.
And of course, there are those who frighten with catastrophic results:
Whatever the cause of the cooling trend, its effects could be extremely serious, if not catastrophic... and cool the planet enough to send it sliding down the road to another ice age within only a few hundred years.
The question of attribution is where the similarity between today's global warming hysteria and the global cooling "concern" of the 70's. Back then it was not clear, at least according to the media, whether the source is anthropogenic or natural:
The changing weather is apparently connected with differences in the amount of energy that the earth's surface receives from the sun.... Man, too, may be somewhat responsible for the cooling trend... climatologists suggest that dust and other particles released into the atmosphere as a result of farming and fuel burning may be blocking more and more sunlight from reaching and heating the surface of the earth.
Of course, the level of hysteria today is also unparalleled. The concerns of the seventies seem like a minor curiosity when compared with the level of global warming propaganda seen today.
If you ask me, today's imminent global warming catastrophe is all taken out of proportion, considering that there is no real evidence to incriminate anthropogenic causes as the main factor behind current day warming. This seesaw between one extreme climate prediction and another doesn't add credibility to the field. Did you hear of the boy who cried wolf?
Comments (9)
Seems to me that there WAS an actual wolf at the end of that story. Analogies aside, it seems to me that the seriousness of a global warming catastrophe would not be mitigated much by whether or not the cause turned out to be anthropogenic.
Yeah that was a real article in fact you can still find it on Time's web site.
http://www.time.com/time/magazine/article/0,9171,944914,00.html
Also remember Y2K hysteria. I even bought an extra propane tank to prepare for that one. I was naive then but now I am skeptical of anyone who predicts catastrophe.
Isn't the fear that a looming ice age could be a possible result of global warming. That global warming could ultimate cause a disruption in the global current conveyor system. The same situation that many scientists point to as a cause for the Younger Dryas event?
In other words, isnt implying that global warming and an ice age are two diametrically opposed outcome somewhat erroneous?
i am also now skeptic of such news.
I remeber during 2005 when the hurricanes were rolling in. Everyone was milking the global warming bucket for what its worth. Now since the hurricanes have stopped. The world has actually cooled down in the past 5 years. The Al Gore and co. fan club have been quiet.
Also there's alot of powerful people in the UN that knows if you can control the global carbon emissions output by all the worlds nations. Then you can control the global economy, and take over the world without firing a shot. These people that plan these things. Are 20x smarter than you and I.
I am dismayed to find that accurate information about the ice age cycle is difficult to find. I'm posting my references in hopes that someone can point me to better ones. My references are based on the temperature proxy data extracted from the ice cores from Vostok, and from Greenland.
Over the past 800,000 years, we've had at least 8 glacial cycles, each about 100,000 years long, consisting of roughly 90,000 years of advancing ice followed by roughly 10,000 years of warmth. Sometimes, the warm period has been up to 23,000 years long.
http://www.sciencemag.org/cgi/content/abstract/289/5486/1897
http://www.sciencemag.org/cgi/content/full/289/5486/1897
We appear to be around 14,000 years into the current warming period.
We know this because they measure deuterium in the ancient ice cores, and derive the temperature record from that. They've currently got ice cores, and the temperature record they provide, going back about a million years.
This National Geographic web page mentions that the highest and lowest temperatures obtained from analysis of the ice cores spanning the past 800,000 years occurred during our most recent glacial cycle. The hottest temperature was 4.5 degrees Celsius warmer than today. That was 130,000 years ago.
http://news.nationalgeographic.com/news/2007/07/070705-antarctica-ice.html
It seems interesting to me that record high and low temperatures, and the glacial maximum, for the past 800,000 years were set during this most recent glacial cycle!
Given that the maximum temperature during the last warming phase was about 4.5 C warmer than today, it seems likely that we'll continue to see much warmer temperatures during this warm phase, just due to the natural glacial cycle.
This source gives a history of the science behind our understanding of the past glacial cycles.
http://www.aip.org/history/climate/cycles.htm
It seems to show that the end of this warm period is fairly near.
This is a very readable book on the ice age cycle, and global warming, written by Astrophysicist Professor Muller, at Berkeley
http://muller.lbl.gov/pages/iceagebook/history_of_climate.html
I welcome factual corrections, additional information, or education.
Chris Shaker
Where are we in the ice age cycle? Temperature wise, we are only a little more than halfway to the usual temperature peak during a typical interglacial (warm period between glaciation).
We are still 4.5 C cooler than the peak temperature during the previous interglacial, which was 130,000 years ago. Temperature varies by 10 to 11 C over the 100,000 year glacial cycle.
Here is the last 420,000 years of the glacial cycle, showing the 100,000 year cycle proxy temperatures derived from the ice cores at Vostok
http://en.wikipedia.org/wiki/Vostok_Station
http://upload.wikimedia.org/wikipedia/commons/7/77/Vostok_420ky_4curves_insolation.jpg
Note the repetitive temperatures variation of 10 to 11 C over the 100,000 yr glacial cycle.
Considering that we are still 4.5 C below the typical temperature peak during an interglacial, ie - only a little more than halfway through the typical 10 - 11 C temperature swing we experience during the 100,000 year glacial cycle, you can usually expect more global warming during this interglacial (warm phase) with or without mankind.
This article says that we are still 4.5 C colder than the max temperature during the previous interglacial,
which occurred 130,000 years ago
http://news.nationalgeographic.com/news/2007/07/070705-antarctica-ice.html
It appears that the sea level naturally changes around 33 ft over the course of the 100,000 year glacial cycle, according to this article
http://www.scientificamerican.com/article.cfm?id=ice-core-reveals-how-quickly-climate-can-change
If CO2 was as powerful as the alarmists say, wouldn't we be warmer than this?
Chris Shaker
Are you curious about the glacial cycle, and where we are in it? Wikipedia has about the best description I have found
http://en.wikipedia.org/wiki/Glacial_cycle
Note the 10 to11 C delta in temperature over the 100,000 year cycles on the right side of the graph
http://upload.wikimedia.org/wikipedia/commons/7/77/Vostok_420ky_4curves_insolation.jpg
Note that the time period is about 100,000 years per cycle, and the delta in temperature is about 10 to 11 C over that time period. Note that the present day is on the left side of that graph.
The reason the temperature line is so much thicker towards the present day is that we have many more ice samples from that time period. Ice compresses the ice below it, so we get fewer samples per time period from the deeper ice layers.
Here is another view of the cycle, from the EPICA ice cores at two locations in Anarctica. On this graph, the present day is on the right. Very similar total delta in temperature, again about 10 C or so. Again, about a 100,000 year period.
http://en.wikipedia.org/wiki/File:Ice_Age_Temperature.png
We have ice cores taken from Vostok and from Greenland, going back through almost one million years of climate history, covering at least 11 glacial cycles over the past 800,000 years.
Scientists measure the deuterium trapped in the ancient ice cores, and derive a temperature proxy record from that. This National Geographic article talks about it
http://news.nationalgeographic.com/news/2007/07/070705-antarctica-ice.html
Each glacial cycle usually consists of about 90,000 years of slowly advancing ice followed by roughly 10,000 years of rapidly warming interglacial (brief warm period between glaciations). Looking at these graphs, we see that the warming at the start of an interglacial is almost vertical. The earth always warms very rapidly at the beginning of an interglacial period. The longest interglacial over the past 400,000 years was 28,000 years long
http://news.nationalgeographic.com/news/2004/11/1110_041110_antarctic_ice_2.html
We appear to be around 10,000 to 14,000 years into the current warming period. We are still 4.5 C *cooler* than the usual peak temperature achieved during an interglacial!
Remember that the delta in temperature during the 100,000 year cycle is 10 to 11 C, and we're only around 6.5 C up from the lowest? If CO2 is so powerful, why is the climate still so cool?
It appears that the longest interglacial we know of over the past 420,000 years was 28,000 years long
http://www.geotimes.org/aug04/NN_icecore.html
One question I've got about the WikiPedia page is why they claim that this interglacial might not end for another 50,000 years. The longest interglacial we know about from the ice cores is 28,000 years long, and we're already at least 10,000 to 14,000 years into this one.
What causes the glacial cycles? It appear that the largest driver is the earth's orbit. Read about Milankovitch cycles
http://en.wikipedia.org/wiki/Milankovitch_cycles
This source gives a history of the science behind our understanding of the past glacial cycles.
http://www.aip.org/history/climate/cycles.htm
It seems to show that the end of this warm period is fairly near.
This is a very readable book on the ice age cycle, and global warming, written by Astrophysicist Professor Muller, at Berkeley
http://muller.lbl.gov/pages/iceagebook/history_of_climate.html
I welcome factual corrections, additional information, or education.
Chris Shaker
"Variations in the Earth's Orbit: Pacemaker of the Ice Ages.", Hays JD, Imbrie J, Shackleton NJ, Science. 1976 Dec 10;194(4270):1121-32.
" 7) A model of future climate based on the observed orbital-climate relationships, but ignoring anthropogenic effects, predicts that the long-term trend over the next seven thousand years is toward extensive Northern Hemisphere glaciation."
http://www.ncbi.nl/