That is incorrect. The oceans act like a high capacity heat sink when stimulated by a sustained thermal forcing function.
If no thermal forcing function exists then it will maintain whatever steady state it is in. Otherwise, the oceans will take up a portion of the excess heat with extremely long response times.
I have quite an elegant way of applying the heat equation to this system.
http://theoilconundrum.blogspot.com see the post on the missing heat.