Regarding Menzies' fantasy and his sending the Chinese around the world and the North pole in 1421, it might have been possible to overlook your mischaracterization of the 'evidence' as "scant", when it is non-existant; however, your "uh" hesitation, indicating some care and reflection taken in choosing the word "scant", which is the wrong word, suggesting there actually is some evidence, makes it unforgiveable. Too bad you equivocated; too bad you were not better informed and could not write plainly, the evidence 'is non-existant'.

Lord Monckton may have been taken in by the book "1421" but the Wall Street Journal only quotes him as having read the UN reports on climate change. Monckton noted that the latest report had milder predictions than the older reports. Criticizing Monckton is only sensible if he had mis-read the UN reports. He hadn't.

Andrew Leonard utterly failed to criticize the Editorial or Moncktons reading of the reports. Instead, Leonard brought up other events of no bearing whatsoever on the Editorial.

The Norse people who settled in Greenland around AD 1000 managed to hang on for about 400-450 years before they were wiped out ... by a climate that turned colder and by refusal to learn from the Inuit: the Norse apparently reached Greenland from the east before the Inuit got there from the west. If the Arctic were ice-free in the 1400s, the Norse in Greenland would not have been wiped out by the loss of all their crops and livestock. The idea that the Chinese found an ice-free Arctic is just bats.

Jared Diamond's Collapse has a detailed discussion of the fate of the Greenland Norse.

I don't think there's any dispute that the Chinese had a navy at the time. So it's hard to call it imaginary. Now, whether or not they discovered America is another story.

There is the mystery of the missing Chinese Fleet that sailed the Great Eastern Ocean, apparently landed at many spots on the wetern coasts of the Americas, and then disappeared.