Just how rapid is the current rate of warming of the ocean? There is an interesting new article by Rosenthal and collaborators in the latest issue of the journal Science entitled "Pacific Ocean Heat Content During the Past 10,000 Years" that attempts to address this question. The article compares current rates of ocean warming with long-term paleoclimatic evidence from ocean sediments. So how rapid is the ocean warming? Well, for the Pacific ocean at least, faster than any other time in at least the past 10,000 years.
The study finds, specifically, that (to quote Columbia University's press release) the "middle depths [of the Pacific Ocean] have warmed 15 times faster in the last 60 years than they did during apparent natural warming cycles in the previous 10,000".