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The Millennia After Tomorrow?
frankthechicken writes "Analysis of a three-kilometer-long ice core drilled from the Antarctic, has revealed our planet has had eight ice ages during that period, punctuated by rather brief warm spells - one of which we enjoy today. And fortunately, the end of the world is not the day after tomorrow, instead it may be expected on Sunday, 17000."
I've read somewhere, that there is a current of thought that the Ice Age was unleased by the global warming period, and that it's a sort of "correction" for global warming. Let me explain in more detail:
Global warming causes less ice at the poles(not really anyone notices), that turns up as coastal water, that water absorbs more heat from the sun, and keeps it in water(away from land), this in turns makes the land colder and colder, until bam you have an ice age. Exactly how long it lasts is until the sea freezes back enough that the landmass can regain its prior heat.
N.B. Global warming is a global phenomenon, nothing in it says humans have to be anywhere near where it's warmer... That's why we don't much like the idea...
Hmm... it's a surprise to see this on Slashdot. I suppose some explanation is in order.
I'm part of an isotope science research group at my university (please, no pasting links - they're not that hard to find anyway). I'm just finishing my honours degree on new meteorite dating techniques, but other students/professors/staff do a lot of work on heavy metal contamination of the environment (mainly lead as an indicator of industrialisation and global dust levels, and indium and bismuth as volcanic indicators). We collaborate with a number of research groups around the world, including the one in Grenoble and others in Venice and Tasmania.
The work we do mainly involves Thermal Ionisation Mass Spectrometry (TIMS - uses a solid sample), while other labs use TIMS as well as Inductively Coupled Plasma Mass Spectrometry (ICP-MS - uses a liquid or gas source). We have and are analysing the Vostok, Dome C and Law Dome samples. One professor in my lab has used TIMS to show how the lead in the ice cores has risen dramatically in response to such events as the Roman Empire processing large ore bodies (to make weapons, shields etc - this was published in Nature ~1994) and also the start of the industrial revolution. Our general focus at the moment is completing a climatic record going back as far as we can. However, due to the extreme cleanliness of the ice cores, processing must be carried out in Class 10 clean rooms (initially at sub-zero temperatures to prevent the ice from melting) to prevent contamination. We routinely measure amounts of lead on the order of a few picograms (10^-12 grams) or less. It is rather slow going.
To give an idea about the problems involved in drilling the ice cores, you have to realise that 3km underground there is a lot of pressure due to the weight of the ice sitting above. 3km is roughly Antarctic bedrock, which is a far down as we can drill. The further down you go, the denser the ice becomes and hence harder to drill. However, you can't just speed up the drill to get the ice faster because you will melt it. The last few hundred metres before bedrock will take a lot longer to drill than the ice above it.
The initial decontamination procedure of the ice cores is somewhat lengthy and inconvenient. As we are looking to find heavy metals in the ice, we have to remove any contamination caused by the drill. So we use a plastic lathe (all of our lab equipment is teflon and is soaked in 10M HNO3 for about 3 months before use) to strip the outer layers of the ice core in succession (the core samples we receive range from ~0.3-1.5m in length). Keep in mind you are working at about -18 degress C here for about 6 hours at a time - not fun. Then we analyse small chunks of the inner core. The decontamination is normally done in Tasmania, and then we get samples shipped on dry ice to us and other labs around the world. There have been some rather tense moments as planes have been late and baggage delayed!! While I remember, a 30cm ice core might be worth around $30k (total cost of drilling / length of ice recovered).
Um, I think that's most of what I can add without going into extremem technical detail, but I'll try to answer any questions anyone has.
This should actually be modded funny.. for those of you who don't get it, type "convert -40c to f" in google. in other news, a lot of people consider a pound of steel to weigh more than a pound of feathers..