On April 21, 2007 at 11:20, phil said...
Antarctica contains 90% of the frozen water on the planet
Yes, but rate of change may be more significant than total amount (at least over a timeframe of a few decades). My understanding from reading a lot of material on both sides of the issue is that the 6% of ice on neither Antarctica nor Greenland is decreasing by more gigatons per year than Antarctica is increasing, and the 4% on Greenland is increasing by more gigatons per year than Antarctica. The total seems to increasing, but Antarctica is not the major factor in the rate.
But sea levels still seem to be rising (of course not by the absurd amounts Gore claims. Probably not by the amounts the U.N. claims). My understanding is that thermal expansion of the water already in the ocean is the major factor in recent sea level changes, rather than changes in the amount of ice. But ocean average temperature has a complex relationship to ocean surface temperature that the experts on both sides of the issue don't seem to be addressing. It is NOT a simple function of the average lagging behind the surface. I've found no decent explanations on which way the ocean temperature is changing or what is driving it.
so the question of temp change in Antarctica is important.
But even for ice changes, air and surface temperatures seem to be secondary. Where ice is increasing (Greenland) it seems to be primarily due to more snow fall and where it is decreasing it seems to be due to less snow fall.
“During the last 4 interglacials, going back 420,00
years, the Earth was warmer than it is today”.
Who cares! If the natural trend for the next 5000 years would have made it even warmer than mankind will make it in the next 100, that fact wouldn't make it wise to cause that warming over 100 years. (Note I don't believe the left about what warming mankind is causing over the next 100 years. But if they're correct, natural trends over 5000 years wouldn't make it OK).
Geology magazine, 1999 27: 179-182 Article by Anderson
and Andrews on “Radiocarbon constraints on ice sheet advance
and retreat in the Weddell Sea, Antarctica” stated “
Less Antarctic ice has melted today than occurred during
the last interglacial”.
Same response as above.
On April 21, 2007 at 14:12, Anthony said...
1) it is true that earths temperature changes over eons
and that there were colder/warmer times but the evidence
also shows that temperature changes in the past took
a long time to happen (degrees/centuries instead of degrees/years)
Now I need the (seemingly) opposite response to what I just said above. First we aren't talking about a rate difference anywhere near as big as centuries vs years. Second, the rate over the last 18000 years has not been steady. Natural processes have driven the warming at least ten times faster than the average for some periods and in the reverse direction for others. It is not reasonable to conclude the current rate (even if measured accurately) is unusual.
There is serious debate over whether the Medievil warm period and the little ice age were regional events or global. But if regional, it was a pretty large region (at least Europe plus the north atlantic plus arctic and over to the north pacific). The temperature drop at the start of the little ice age (mid 1400's) dwarfs any supposedly man made temperature changes in modern times.
2) that continents and places move, that the earth wobbles....
so that some places that were warmer/colder were that
way because they were different then now and you need
to look at world temp and not (for example) was Antartic
once warm. (it was, partially because it used to be in
a more equatorial position)
Wrong time scale again. Ice age vs. non Ice age timescale is much faster than continental drift of Antarctica time scale.
3) that we know some things that cause the changes and
we know that they are caused by us. so it becomes are
we 90% responsible or 100% or 70% , so why not decrease
the effect we have
I don't believe we know. So if the question is are we 50% responsible or 0%, how much money should we spend fixing something that we don't know is broken but do know that we can't fix.
4) we need to live on this planet, yes there where times
when it was warmer/ colder and there were times when there
were dinosaurs and mammoths, neither of which survived
their climate changes.
Climate change seems an unlikely explanation for either of those extinctions.
