[Titanscape (OP)]

I understand that the sun moves low along the Arctic horizon, perhaps mirrored walls would help it stay cool, by reflecting light back into the sky, and casting a shadow over the ice, long shadows.

They could even be partly made out of ice.

Maybe two metres or eight metres high. Alfoil or reflective plastic on the sunny side, or both sides.

[lyner]

OK in principle but the walls would need to be miles high in order to throw long enough shadows, I think - for the idea to work at a low enough latitude to be useful.

[Don_1]

You’d be in for some bad luck if you broke a mirror that size!

Mirror mirror on the ice
I accidentally broke you
Now I’ve got Lice


I’ll put you back together
If you please
If you would rid me of all the Fleas.


I really didn’t mean it
That I swear
Please call off this Polar Bear


My boat is sinking
In the brine
‘cause I exposed you to sunshine


Oh my word what a shocker
I’m on my way down
To Davy Jones locker.

[dentstudent]

Now I'm here, deep in l'eau
I think I'll be
Jacques Cousteau

[Karen W.]

You’d be in for some bad luck if you broke a mirror that size!

Mirror mirror on the ice
I accidentally broke you
Now I’ve got Lice


I’ll put you back together
If you please
If you would rid me of all the Fleas.


I really didn’t mean it
That I swear
Please call off this Polar Bear


My boat is sinking
In the brine
‘cause I exposed you to sunshine


Oh my word what a shocker
I’m on my way down
To Davy Jones locker.

That's quite the poemage!

[LeeE]

Just painting it all white would be almost as good as mirrors... er...

[Titanscape (OP)]

Yes, can't paint ice though.

Pure white reflects well, everyone knows.

Cheap plastic mirrors work, alfoil...

[LeeE]

The point I was trying to make is that the ice and snow is already highly reflective and using mirrors would only have a minimal effect.

[lyner]

The place for your mirrors / white paint is the Sahara Desert.

[SETF]

hi. but wont maintenance be a pain also (financially)

[Don_1]

Yes, a real pain in the glass!

[Titanscape (OP)]

If these walls were only a few hundred metres high, it would cast a great shadow, and slow, and maybe stop melting because the inner part, near the pole, might not altogether melt as is, or only will if the edges melt and absorb heat energy.

[tony6789]

a very far off idea but u have to think of wild life and the vast amount of mirrors that would be needed but i suppose it is possible for it ta work...but then ethical reasons. global warming is natuaral(my opinion) and if u feel the same way then u will understand that this is another example of man trying to defy earths natural cycle and could result in a bad effect years from now

[Titanscape (OP)]

Yes, I suppose it's not the sun but the air that warms and melts the ice.

[tony6789]

Yes, I suppose it's not the sun but the air that warms and melts the ice.

but the air gets warmer/colder based on how much sunlight it recives

[Titanscape (OP)]

I thought that was dependant on the ground, it's colour and the angle of sunlight.

[tangoblue]

there would have to spend a lot of money on it and how would they keep the mirrors maintained and stop them from sinking/moving when the ice and snow melted/moved.

[Titanscape (OP)]

They could make them from durable plastic, considerable length each piece, flexible joints, casting 2 km shadows, at shadows end the next one. With tunnels here and there for bears... Diagonal tunnels.

Wind storms a problem though.

And the bases could be really wide, a little long, and a metre high. So 400 m, 4 m and 1 m.

Perhaps fixed in drilled holes.

[paul.fr]

Scientists to stop global warming with 100,000 square mile sun shade
Scientists claim they can fight global warming by firing trillions of mirrors into space to deflect the sun's rays forming a 100,000 square mile "sun shade".

According to astronomer Dr Roger Angel, at the University of Arizona, the trillions of mirrors would have to be fired one million miles above the earth using a huge cannon with a barrel of 0.6 miles across.

The gun would pack 100 times the power of conventional weapons and need an exclusion zone of several miles before being fired.

Despite the obvious obstacles - including an estimated $350 trillion (£244trn) price tag for the project - Dr Angel is confident of getting the project off the ground.

He said: "What we have developed is certainly effective and a method guaranteed to work.

"Tests are ongoing but we expect to be ready to launch within 20 or 30 years time. Things that take a few decades are not that futuristic."

Dr Angel has already secured NASA funding for a pilot project and British inventor Tod Todeschini, 38, was commissioned to build a scaled-down version of the gun.

He constructed the four-metre long cannon in his workshop in Sandlake, Oxfordshire, for a TV documentary investigating the sun shield theory.

He said: "The gun was horrendously dangerous. This was the first gun I'd ever built.

"I knew I could put it together safely but at the end of it all I didn't know what I was going to get.

"It was immensely dangerous. I was attempting to build a gun to produce 1,500G of force but it ended up creating about 10,000G and we had to turn the power down.

"Most weapons used by the army produce 100Gs of force so our gun was about 100 times more powerful.

"The main danger was electrocution because it used enough power to boil 44,000 kettles.

"If you were working with normal levels of electricity you could get a shock and be fine, but if you got a shock off this you would be dead - no question.

"We've proved it's possible to build a scaled-down version of the gun needed to get these lenses into the air so it's just a matter of scaling up the designs for the real thing."

If Dr Angel's sun shield is successful he says the mirrors will last 50 years before needing to be replaced.

"What you are talking about is a project which will stop global warming for centuries to come," he said.

"At the moment the sums involved sound huge but in the greater scheme of things it's a price worth paying.

"Over 50 years the mirrors will become damaged and therefore fresh lenses will need to be fired into space to ensure the shield is constant."

Dr Angel, who pioneers solar energy, is developing cheaper methods of making the lenses to bring the cost of the project down.

In the meantime researchers at the University of Victoria, Canada, are testing the sun shield theory by using computer simulations of the project.

Dr Angel's sun shield theory will feature on Ways to Save the Planet on the Discovery Channel at 7pm on Sunday.

http://www.telegraph.co.uk/earth/environment/globalwarming/4839985/Scientists-to-stop-global-warming-with-100000-square-mile-sun-shade.html