This forum is about wrong numbers in science, politics and the media. It respects good science and good English.
So the phenomenon was restricted to the area where records of how life was lived have survived. Of course there are no writings from the southern hemisphere or the american continents to demonstrate how hot it was there. How convenient.
This is a pretty good article which discusses whether the supposed beneficial heating effect of the Gulf stream is real or not. The author reckons that it's an "urban myth".
Here's the articl for those itnerested.
As Our Valiant Host says, the truth is really in the name. "New Scientist" indeed.
Just for the record, McIntyre and McKitrick cannot be "disproved" by new temperature reconstructions, because they WERE NOT OFFERING AN ALTERNATIVE RECONSTRUCTION to the Mann et al Hockeystick, as they have stated time and time again. They're not experts on climate, and acknowledge their limitations.
Instead, the two Canadians were criticising Mann's METHOD of achieving the Hockeystick graph, showing, among other things, that the statistical method used ALWAYS produces Hockeystick shapes, even when fed with random data (called "Monte Carlo test").
This "talking point" the warming enthusiasts accelerated away from as fast as they possibly could, and for good reason.
The continuing collection of published papers around this subject to be found here
seems to be a good starting point.