Commodity prices and monetary policy

We have always known that the Federal Reserve has the tools to prevent inflation but whether they choose to use it or not is another matter. Recent studies have shown that there correlation between the changes in prices for the different commodities have increased over time. Take for example, two commodities, copper and oil. Just ten years back, the two commodities prices were not related at all. During that time, when the copper prices went up, the oil prices were just as likely to go down. However in recent years, the prices of both commodities seem to move in tandem. However the positive correlation does not mean that the increase in one commodity has caused the other to rise. Instead, it just shows that there are some similar factors that are affecting the market in the same way.
Another change in the correlation of the market is between the exchange rate and commodities inflation. For instance ten years ago, the correlation was actually negative as the weakening US economy cause both the value of the dollar and the price of oil to fall. However in the past couple of year, the correlations have become stronger and positive. Just last year, the dollar depreciated sharply and this has led to an increase in the prices for copper and oil. It would be interesting to see how big an increase in commodity prices we would get given the continuing slide of the US dollar and the strength of the correlation currently. It is very evident even now, as the current rise in oil prices is heavily blamed on the weak US dollar. This is also the same for other commodities like gold and copper. Therefore there is a strong case for the Fed to step in as the bout of commodity inflation has proven to be brought about by monetary policy.