I'm John Batchel, visiting with Professor Peter Frankapan, who of Oxford University.

His new book is The Earth Transformed and Untold History.

And we now go to a period that is striking in that Scandinavians now take a role

as does climate

because of the cooling of some temperatures

before the medieval warm period

and then suddenly the warming

that was created in the dates,

especially between 9.50 and 1250.

And again, Peter, I circled in my notes, low volcanism, correct?

That is the explanation for why this period is so stable.

That's one of the, that's one of that's, that's, that's, that's, that's, that's, that's, that's, that's, that's, that's, that's, that's a prime reason, but the natural cycles are also important in that, but also the ability to be successful. So that those, those changes provide motivations and incentives and rewards to look out for new pastures, either because, for example, changes of wind direction or intensity,

or because of resource shortage, there's, there are pressures and pulls and pushes to

look at new worlds. And in fact, those expansions of the Vikings out into the North Atlantic

towards first Iceland, then Greenland, and then Newfoundland are mirrored, there's about the same time, the

same process by peoples in the southern oceans of the South Pacific, where there's a whole series

of colonisations of new areas and new islands that have never seen humans before. And again,

we can date some of this because of new scientific data and technologies.

But in the case of the North Atlantic, some of the drive was towards,

because it was to do with movements of shoals of fish further northwards into cooler waters as a result of the warming patterns.

Some to do with the fact that these new lands that were discovered offered new new abilities, new goods to trade,

for example, walrus in large quantities that was very important, the walrus hides making high

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