The headline-ese will be seized on as an anti-AGW "aha" moment but really? this is science doing scienting. The models can't explain the period because it's not a CO2 driven event. So, the models need adapting and the current contribution understood. Does this invalidate AGW? Nope. Nor does this ocean current on it's own slam dunk the reasons why the warm period happened. It's a theory backed by indirect evidence from animal population studies.