If anything might smash global markets right now, it would be a China implosion, not a US one. Rather than watch the flawed Baltic Dry Index, the better place to watch for a China slow-down is directly via its consumption of commodities.
Notably, Chinese steel prices have fallen 20-25% since their August peak, and a survey from Danske Bank shows that iron ore imports are expected to fall. If these expectations materialise, it could be an early sign of a Chinese slow-down.
Danske Bank: “Participants in our monthly survey on Chinese iron ore imports expect the import level to fall to 48 million tonnes during October and November (compared with the record level of 58 million tonnes in July). There is clearly a more negative tone in our survey this month than last month”
(Via Dankse Bank, “Survey On Chinese Iron Ore Import”, 18 September 2009)