The oil market is heading into what Fatih Birol calls the "red zone" this summer. Speaking Thursday at Chatham House in London, Birol warned that rapidly falling inventories, missing Middle Eastern exports, and rising summer demand could push global oil markets into dangerous territory by July or August. "This may be difficult and we may be entering the red zone in July-August if we don't see some improvements," Birol said. And unlike some earlier warnings that felt a bit theoretical, the inventory data increasingly suggest he may actually have…