In a full-information equilibrium in a liquid market, the forward price should exactly equal the spot price plus the carrying cost (storage cost plus foregone interest)[NOTE: I updated this to change the typo that the first comment caught, good catch!]. Thus you can explain the current increase in the crude spot price as driven by an increase in current quantity demanded because of the arbitrage opportunity between the spot price and the expectation of the price of the forward at contract termination, assuming constant carrying costs.
Isn’t economics cool? I’ve been marveling over this all morning. But the missing piece here that I’d like to understand better is the market fundamentals that are driving the expectations of greater relative scarcity later in 2005. What’s driving the high futures prices? Expectations of lower quantity supplied, higher quantity demanded, or both?