conveneience yield and futures

why does the convenience yield imply that spot is higher than the future. If supply for a commodity is cutoff, i understand how the spot prices would rise (due to limited supply) but why would the futures prices particularly be lower than the spot prices?

Having convenience yield doesn’t necessarily mean that futures prices will be lower than spot prices, just as having storage costs doesn’t necessarily mean that futures prices will be lower than spot prices.

It all depends on the magnitude of the convenience yield or storage costs compared to the risk-free rate.

why do future prices go up when the storage costs are higher?

If you sell me gold will you charge me the same price if I pick it up today as you will if I pick it up in a month?

Because the other guy is ensuring you future delivery of goods at a locked price and is himself currently bearing the storage cost hence he will charge you for the storage cost

It all depends on the magnitude of the convenience yield or storage costs compared to the risk-free rate. real value here