sorry, that was a poor choice of words. I've just read a lot of folks' comments about high carbon rusting and actually being more brittle in severe cold weather
http://www.bladeforums.com/forums/showthread.php?t=705792
Also the high praise Fallkniven gets for its VG10 laminate and how its a preferred blade type in the cold scandinavian region
For what it's worth, brittleness (under any conditions, cold or not) can affect any steel, stainless or carbon. Personally, I think it's got more to do with the quality of the heat treat & tempering. And there are many different types & grades of 'plain' carbon steel, just as with stainless. Some, I'm sure, are better than others. As would be the case with any knife, it has more to do with the quality of execution than anything.
The reason laminated blades get such high praise, is due to the outer layer of steel being at a lower hardness (therefore less brittle) than the 'core' steel in the middle, which forms the cutting edge. The edge itself is harder, which gives it better edge retention. The outer layer, being softer, gives the blade a somewhat flexible backbone, which allows it to be more resistant to impact & shock. All of these qualities could apply just as equally to carbon or stainless. It has much more to due with the heat treat & tempering of the two different steels in the blade.
Personally, I think we may hear more about carbon blades breaking under severe conditions just because carbon steel makes up a very large (& popular) portion of the the big, chopper-type, camping fixed blades on the market. There are a lot of 'em out there, so it stands to reason we'll here more 'anecdotal' accounts of failures under extreme use.
As previously mentioned, the plain carbon blades do rust (obviously). But, a lot of people are willing to accept the higher maintenance expectation of a carbon blade, in trade for what many believe will be a superior cutter. Not to mention, many people prefer carbon blades over the 'super' steels simply because they're so much easier to sharpen to a great edge, using conventional tools.