. . . . . Ir.S.S.R. Kwee Computer ConsultancyFor some time I wanted to write something on hypes as global warming, nuclear energy, etcetera. As this has many aspects, and I don't really have the time to work this out, here are some of my notes.
ijstijden.notes Roland Kwee 17 sept 2008
ice age: geological period with continental ice sheets, polar ice caps, alpine glaciers.
http://en.wikipedia.org/wiki/Ice_age
Between age ices: no significant ice sheets, very high sea level.
Recent ice ages: about 10.000 years ago, with 1000-3000 meter ice sheets over large parts of Europe and North America, and sea level some 120 meters below that of today, dry passage between Europe and England, dry Bering Street.
But factually today is also an ice age because of the ice on the Poles, and glaciers on Greenland and the Alps etc. This ice age started about 2.5 million years ago. This ice age is called the Quaternary Ice Age, i.e., the fourth one, because there were three earlier ones.
Within this 4th ice age there are relatively warmer and colder periods. The latter ones are often called "ice age", but "glacial period" would be a more accurate description. The most recent glacial period lasted from about 70.000 to 10.000 years ago.
More recently, Little Ice Age http://en.wikipedia.org/wiki/Little_Ice_Age lasted from about the 13th century (Middle Ages) to about 1950. This period was characterized by cold winters with lots of snow and ice, frozen rivers, ice skating, lost harvest, famines etc. The observation that recently winters are getting less cold, with little chances for ice skating, etc etc, might be an indication that we are now experiencing a warmer period following this Little Ice Age.
Even more recently, during the years 1945-1975 the average temperature on Earth was falling, and scientists were fearing the coming of a new "ice age". This period is also sometimes referred to as a "little ice age".
In about ten-thousand years from now the following glacial period or "ice age" will start.
The real end of this (4th) Ice Age will be when the ice of both poles, and Greenland, will be melted. The north pole will melt first, as it has only a 3 meter thick ice sheet of frozen sea water, which is salt, and will melt at temperatures well below zero Celsius.
The south pole, however, has an ice sheet of about 3 thousand meter thick, resting on land This will only melt after the continent has drifted more towards the equator. The south pole ice cap was formed some 20 million years ago, and it will take some million years before it will be disappeared. In the mean time, many more glacial periods will happen.
The other three real ice ages were:
The earliest hypothesized ice age, called the Huronian, was around 2.7 to 2.3 billion years ago during the early Proterozoic Eon.
The earliest well-documented ice age, and probably the most severe of the last 1 billion years, occurred from 850 to 630 million years ago (the Cryogenian period) and may have produced a Snowball Earth in which permanent ice covered the entire globe.
A minor ice age, the Andean-Saharan, occurred from 460 to 430 million years ago.
There were extensive polar ice caps at intervals from 350 to 260 million years ago, during the Carboniferous and early Permian Periods, associated with the Karoo Ice Age.
As said, the current ice age started some 20 million years ago when the ice sheet on the south pole began to grow.
With regard to the time scales:
The earth was formed some 4.6 billion years ago.
Some 4 billion years ago the first, primitive, simple cell live forms appeared. http://en.wikipedia.org/wiki/Timeline_of_evolution
About 3 billion years ago organisms started to use photosynthesis, the basis of plant life.
About 1 billion years ago multicellular life appeared.
600 million years ago simple animals appeared.
500 million years ago the first fish appeared.
200 million years ago the first mammals appeared.
65 million years ago the dinosaurs died out.
some 2.5 million years ago the first humans appeared, using simple stone tools, begin of the Stone Age. http://en.wikipedia.org/wiki/Stone_age
200.000 years ago the humans started looking they do today.
About 6000 - 2500 years ago several cultures learned to make metal objects, begin of the Bronze Age.
about 5000 years ago the first civilizations appeared, i.e, China, Babylon, pyramids, with writing systems.
Some 3000 years ago the Iron Age began.
Prehistory ends with the first written records, some 5000 - 2000 years ago.
http://en.wikipedia.org/wiki/Prehistory
As a comparison, the proponents of nuclear energy plan to store huge amounts of very dangerous radio-active waste for about 150.000 years for it to become harmless.
Another comparison: most carbon deposits formed over about 300 million years is produced and burned in the past 100 years, and current reserves will only last for some 50 more years. The anticipated "huge" amounts of oil beneath the north pole will only serve for some 7 years of current world consumption, and gas from the same place for some 30 years.
Global Warming as a concept is based on the Hockey Stick theory, showing a particular global temperature trend over the last 1.000 years. Al Gore even talks about ice core climate research going back 400.000 years.
Delft University of Technology geology professor Kroonenberg:
Homo Universalis: Salomon Kroonenberg, lezing 15 mei 2008 http://www.deburen.eu/?language=fr&p=programma&c=5&id=209 with comments by a critic
Kroonenberg: Koelt het klimaat weer af? Discussiestuk, 3 pagina's, mei 2008 http://www.deburen.eu/uploads/documents/Salomon%20Kroonenberg-Koelt%20het%20klimaat%20weer%20af.pdf
Het klimaat laat zich niet sturen (Trouw, 24 februari 2006) http://www.tudelft.nl/live/pagina.jsp?id=3e341fe6-03db-429b-a34c-119c4b202a1b&lang=en
De aanblik van de aarde over tienduizend jaar, Prof.dr. Salomon Kroonenberg (TU Delft), 'Prof. Baarda-lezing' tijdens het GIN Symposium 2006 op 15 november 2006, (Koninklijke Nederlandse Akademie van Wetenschappen) http://www.ncg.knaw.nl/Studiedagen/Lezingen/06Kroonenberg.html