 Now, if we go back further in time, and we start to talk about climate cycles over tens of millions of years to hundreds of millions of years, we have cycles in that too. And that's driven by tectonics. So many of you would have heard about Pangea and Gondwana coming together and then breaking up again. What geoscientists have put together, and we're still putting this together as we go back further in time, is that this has happened many, many, many times over the past three, four billion years, continents of Coal West, and then broken apart. And one of the fundamental reasons for this kind of cycle, which is some times called the Wilson cycle, is that deep seafloor can't age beyond about 300 million years before it's subducts. It's just self-subducts. So if you look at the ages of deep seafloor today, you'll find nothing older than about, oh, say 280 million years.