Greetings,
Well this has been interesting. In spite of my request
to not worry about the validity of the assumptions, that
is precisely what 95% of responders did.
sigh
Think of it this way.
There is this great big weather machine.
Do we undertand how it works?
What will it do if we set different initial conditions?
[Aside: this is sometimes called a 'what-if' scenario.]

Assume X, Y & Z. What is the resulting weather?
[What are the critical factors?
See IPCC: 6.13 Global Mean Radiative Forcings
http://www.grida.no/climate/ipcc_tar/wg1/251.htm]

*** If you don't like the assumptions,
treat it as a thought exercise.***

Assume the average global temperature rises 8C by 2500.
Assume the Arctic is ice free in the summer.
[Note that a lot of relevant IPCC factors are not specified.]

1) What would be the effect on the circumpolar vortex?
2) What would be the effect on the jet stream?
3) What will be the effect of an ice free Arctic on North
American, [& northern hemispheric] weather patterns?
4) Will the prevailing winds be shifted or re-oriented?

It is the mid-North American weather patterns in which I am most
interested. The weather here is roughly a result of the
interaction of Arctic circulation and Pacific fronts which
usually come up from the south west. How will that change?
Further desertification? New wind patterns?

curious
-het






--
"Humanity is performing a 'great geophysical experiment', not in a laboratory,
not in a computer, but on our own planet." -R. Revelle & H. E. Suess(1957)

Global Warming: http://www.autobahn.mb.ca/~het/globalwarming.html
H.E. Taylor http://www.autobahn.mb.ca/~het/