Hello and welcome to the History Extra Podcast from BBC History Magazine, Britain's

bestselling history magazine.

I'm Ilicore Thorn.

In today's episode, you'll be hearing from Dr Helen Chersky, a physicist and oceanographer.

In December 2020, Helen presented one of the three Royal Institution Christmas Lectures,

in which expert scientists from different fields presented a unique user's guide to planet

earth.

You can watch that in full on BBC eye player.

Helen's lecture, called Waterworld, looked at the oceans as an engine, exploring how they

played a critical role in generating weather, providing food and connecting trade routes

throughout history.

We spoke to Helen last month shortly before she delivered the lecture to find out more.

Putting the questions to her was our acting digital editor, Eleanor Evans.

Your Christmas lectures are going to look at the impact of human activity on our planet

and explore a lot of the links there.

Can I ask you how do you go about tackling a subject as vast as the links between human

civilization and the ocean?

With difficulty.

I'm also writing a book on it, which is actually in a way it's better because there's

more space, but it's worse because there's even more you could include and so you have

to make even more decisions.

In some senses, from my point of view for the ocean, it helps a little bit because no one

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