Snowball earth appears to have been due to a feedback loop (once you glaciate a significant amount of the planet, the rest follows). I don't know what the trigger was, however. A supervolcano is possible, blocking sunlight over a long enough period.
On 13 March 2014 05:56, John Clark <[email protected]> wrote: > On Tue, Mar 11, 2014 at 2:17 PM, <[email protected]> wrote: > >> >>> >>> I think on the scale of 4 billion years the sort of margin we're >>>> talking about is that necessary to keep water liquid on the surface. >>>> >>> >>> >> At least twice in the last 4 billion years water WAS kept below the >>> freezing point at the surface, from the pole continuously to the equator >>> and we had a snowball Earth. It happened once about 1.5 billion years ago >>> and again about 700 million years ago; why it happened and once it did how >>> things ever warmed up again is not well understood, just like most things >>> in climate science. >>> >>> >> >> > I knew you'd say that. So what if there are two periods or more when >> liquid water wasn't free running. Does that alter the fact that liquid >> water has been *roughly* in situ over billion years while the sun warmed >> 20%? Do you actually dispute that this is something that needs explaining? >> > > No and I don't claim to know all the answers, I'd like to know why the > Earth turned into a snowball from pole to equator .7 billion years ago but > from 1.5 to .7 billion, when our star was even weaker, it did not and > despite a weaker sun things were much warmer. Apparently the climate > machine is a bit more complicated than what some would have us believe. > > > Several posts up, you obviously did not know about the sun warming >> issue. >> > > BULLSHIT! I would be willing to bet money that I know more about the > evolution of stars, both on and off the main sequence, than you do, and > probably one hell of a lot more. > > >>> You keep throwing out eratic graphs....you do know they are provided >>>> by climate science? >>>> >>> >> >> So you think climate scientists are putting out "eratic graphs" but >>> nevertheless based on what they say you think the human race should be >>> forced to be put on a starvation energy budget that will impoverish the >>> world and kill billions of people. And this is the moral high ground? >>> >> >> > > I don't know what the fuck you are talking about. >> > > That's a pity because you're the one who said climate science are > producing "eratic graphs". > > > They are doing science. The discussion about what needs to happen is a >> separate matter. >> > > Yes, and the question about what has happened is a separate matter from > what will happen, and one question is far far more difficult to answer than > the other because the past is always clearer than the future. > > > Fuck off >> > > I love you too. > > John K Clark > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
