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Antonia
Guest
#Please read the science a little more carefully. We are at the moment in a generally cooling part of the Milankovitch cycle. In fact the rapidly warming phase of the cycle happened about ten thousand years ago and we seem to have come through that OK. But before everyone gets all excited about that and starts thinking that it's the answer to our prayers, we all need to understand the science. Or, failing that, at least the graphs. We have another 100,000 years to wait before we can hope for any help from our Serbian friend.
In very handwaving terms, the Milankovitch cycle describes observations of several, different, superimposed cyclic fluctuations which result in cyclic (although complex) changes in global surface temperatures of the order of ten degrees Celsius. These changes take place over something like 100,000 years. This means that as far as Milankovitch cycles are concerned, we are discussing changes in the order of 0.0001 degrees Celsius per year or 0.1 degrees per millennium.
The global warming that we're worried about in this thread, whatever the source(s), is happening at a rate of about 0.1 degrees in five years, that is a couple of hundred times faster than anything that Milankovitch can explain. It's much more worrying, because while Milankovitch explains a cyclic tendency of a few degrees over hundreds of thousands of years, the global warming that we see now is not cyclic and it's happening a lot faster. As far as we know at the moment, for all intents and purposes it's permanent, and the physics places no arbitrary limit of a few degrees on the actual temperature rise. We really could be talking eventually about a surface temperature on the Earth which would boil water. It's like that on Venus right now -- the mean surface temperature there is about 460 degrees Celsius. It's primarily the CO2 in Venus' atmosphere which heats the surface to that level, it's not just because of the distance from the sun. Venus is twice as far from the sun as Mercury and so receives only one quarter of the insolation that Mercury receives. But Venus is generally hotter than Mercury because Mercury has no atmosphere to speak of.
All the science I'm describing here is readily accessible on the Internet, see Wikipedia for example, and it is not seriously disputed.
We are now seeing changes in human timescales which should only be happening in geological timescales. It is staggeringly difficult to make deliberate changes to the planet of this order of magnitude, but the consensus is that we've managed to do it. If we stand by and do nothing while these changes continue then the time will probably come, and soon, when we will be unable to do anything effective to reverse them. By then we will at least have a pretty good idea of when the end will come, and what it will be like.
Yes..Correct Ged,
Antonia