posted on Oct, 23 2014 @ 04:17 PM
originally posted by: network dude
a reply to: mc_squared
I know right? I mean, if we weren't coming out of an ice age, I'd be worried. But since we are, that's all kind or logical.
I recently attended a lecture by a scientist on this issue with up-to-date data.
We came out of the ice age 10000 years ago. In the recent history, the interglacials (like now) have been quite short. Most of the time it's an Ice
Age and substantially cooler---the interglacials spurt up in temperature but they don't last.
There's some facts:
a) the Milankovitch driving force from astronomical influences---which can be computed exactly from orbital mechanics and has effectively no
undecertainty as a result----as been DECREASING (i.e. towards cold) since around 8000 BC, so we should be cooling, in the absence of other effects.
The Milankovitch driving went up and up and peaked at the time the Ice Age ended.
b) the Milankovitch effect from orbital mechanics on total incoming solar radiation is quite small, but the effect on northern latitudes, in
particular the parameter often examined is July radiation in 65 N latitude is very large, and that interacts with the ocean circulation and ice near
Greenland.
c) the Earth WAS
cooling slowly on average for the last few thousand years, as one would expect, until the very modern period when humans
started emitting substantial greenhouse gases and changing the land use in a substantial way.
Conclusion: mankind's emission of gases has substantially and very quickly reversed a natural trend, and is only a small fraction of what is likely to
come. We are going to see almost as much an increase on the hot side in a hundred years (Heat Age) as there was on the cold side (taking thousands)
in an Ice Age---when glaciers miles thick covered part of North America and Europe. This will be in a temperature and climate regime not seen for an
enormous amount of time, well before any primates existed.
edit on 23-10-2014 by mbkennel because: (no reason given)
edit on 23-10-2014 by mbkennel because: (no reason given)