As of right now, there are two things I'm watching that could cause global markets to decline:
1) A fiscal cliff disappointment. As much as I'm sick of the fiscal cliff, there are risks things don't play out as expected in the immediate future. I believe, though, any tumble over the cliff will be short-lived.
2) The underperformance of commodities.
I think the lack of enthusiasm in the commodities markets, relative to global stocks and European-bloc currencies, is due to growth expectations; they have been tempered and seem to be keeping commodity prices contained.
Now, will this create investor anxiety? Will watching commodities wallow around cause investors to second-guess the foundation from which other markets are bouncing higher? It's possible.
But it's also possible that investors are content with this dichotomy ...