Why are copper prices so high?

I still can't get over how much copper prices have risen in the last year. It makes it impossible as an estimator to garuantee a bid for more than two days. And it's not just copper that's going up, but aluminum and zink (the most common metal in die cast fittings). Steel prices are also affecting the general contractors, therefore making the customers more liery of even starting a project. I've noticed that in the last few days, copper has actually leveled out a little. Now, whether this trend can continue or not is hard to say. In an artical writen by the AP, most of the demand is comming from China, but now a rise in damand is coming from Europe and Japan. Other factors include large strikes and equipment failiers.
The price of base metals isn't the only thing that's increasing. Theft on jobsites and vacant homes has risen since the return for scrap has reached levels that make you blink your eyes a few times when you hear it. The Union electrical contractors in my area have put names of all thier employees in with all the scrap yards to prevent any wire thefts. The worst part about the whole situation is that there is nothing, as electrical contractors, that we can do. I've seen a few contractors in our city fold due to the sudden increases of prices and decreasing of projects.