One enterprising soul suggested we capture the runoff from Greenland's ice in 55 gallon barrels and store them in our attics to prevent the flooding.

Just for grins:
55 gallons = 0.208197 cubic meters (about 5 barrels per cubic meter of water)

a cubic kilometer is 10⁹ cubic meters
2.1 million cubic kilometers is 2.1 * 10¹⁵ cubic meters

So it would take about 1*10¹⁶ barrels to hold all the water

With 300 million Americans living in almost 100 million homes, we could allocate the barrels to buildings. Each of the buildings would receive 10¹⁶/10⁸ barrels or 100,000,000 barrels.

With a typical lot in America being 60 x 120 feet and a barrel having about a 2 foot diameter, you could place an array 30 barrels wide by 60 barrels long on a lot (1,800). So you would have to stack the barrels to fit them all.

The stack would be 100,000,000/1,800 barrels tall or about 55,000 barrels tall. If a barrel is 3 feet tall we are talking about a stack of barrels 31.5 miles tall. Apparently for this strategy to work we are going to need bigger lots for our homes.

Furthermore, worldwide production of barrels in 2007 was only 30 million barrels. we'll have to gear this production up considerably to produce the 10 quadrillion barrels we'll need. Might I suggest a no-bid contract since this is an emergency.