Research Supports "Snowball Earth" Hypothesis 243
u2boy_nl writes, "A new U.S. study finds evidence for 'Snowball Earth,' the hypothesis that the entire Earth was ice-covered for long periods on several occasions, most recently 600-700 million years ago. The icy conditions (Earth's oceans frozen completely with ice more than a kilometer thick) ended violently under extreme greenhouse conditions — snowballearth.org suggests the meltdown could have occurred in as little as 2,000 years. Snowball Earth challenges long-held assumptions regarding the limits of global change. Wikipedia has more on the hypothesis."
A little explanation is in order (Score:4, Informative)
This is a fancy way of saying that they have found deposits of submarine rock near the equator that should only be forming in an arctic climate, and which date to the period of 'snowball earth' in question. This sediment has magnetic signatures which signify it formed originally at the equator, in an equatorial magnetic field, and did not simply arrive at the equator after having been formed previously in the arctic.
Please note that we are speaking here of a process of lava cooling, and 'trapping' a fingerprint of whatever magnetic field was present at the time it cooled. That's how these fingerprints are formed and it is a well-known and documented process, and a basis for the current models of magnetic field shift.
Had the magnetic system been different in the past (not a two-pole magnetic field) it would have rendered these results useless, but this article itself explains that there is now evidence that the Earth's magnetic field has always been a dipole (two-pole) field and that these results are correct.
At least, that is my understanding.
Re:Cavemen (Score:3, Informative)
Amazing any life lived though that but some plankton made it through and eventually it turned into humans.
The truth is stranger then fiction.
Re:Shoot ... score one for the Bush admin (Score:3, Informative)
Some shred of relevance to the post you are responding to would help too.
The relevance of the article's topic to the current situation is that CO2 as the mediator for precipitous global warming has a precedent. The explanation of how the planet got from Snowball Earth to the Cambrian steambath is based in the same science as the predominant modern theories about the effect of humans turning large quantities of sequestered carbon back into CO2. The theories look a lot more plausible with a very long timescale map that is consistent with the models developed from basic physical facts (like CO2 thermal opacity, he albedo of ice, etc.) and much shorter-time sets of evidence. Snowball Earth looks like an inevitable path to a very dead end except for the fact that it effectively shuts down CO2 sequestration, allowing volcanic release to build levels high enough to counter the self-reinforcing deep freeze with the Greenhouse Effect.
Of course, the problem with this seems to be related to Clarke's Law, that sufficiently advanced technology is indistinguishable from magic (by those who don't understand it.) If you don't understand the science behind modern theories of human-driven global warming, it looks like so much religious bullshit, and more science you don't understand confirming past precipitous warming just looks like more reason to see the whole thing as mystical and beyond understanding. Beyond yours? Apparently so. That's not true for people who do understand the science that is behind both the explanation for why Snowball Earth melted and for why we are now seeing warming that has no precedent in the brief period of civilized history and which runs counter to where natural cycles should be taking the climate.