 Climate change is not something that's just come about recently. We've seen climate change through the entire history of the planet. It's really much harder to monitor three and a half billion years ago than it is today because there were no temperature records or anything like that to live off of. But we do know that there are some times in Earth's history where big climate changes have occurred. And one example is in what they call the Sturtean Snowball Earth event. That's about 700 million years ago and it's well exposed in South Australia. That's the name Sturtean. And during this event in the Snowball Earth it means that the planet went into a cooling trend that could have seen the whole planet frozen. We don't know if it was completely frozen but we know that it was coming down very near the equator which means there was a hell of a lot of ice. Which means it was a bit shutting down weathering and things. And when you talk about the supercontinent cycles that we seem to over history form and unform these big supercontinents. One of these supercontinents, Pangea, existed around a billion years ago and it was sitting near the equator and it was probably relatively dry because it was hard to get the weather into this giant continent. And when it started to break up about a billion years ago that exposed a lot of rocks to weathering. And the silicate weathering cycle which isn't that exciting is actually really important because we can weather the rocks and we can lock up CO2 and we can put it into the precipitate in the oceans and extract CO2 from the atmosphere and put it into rocks. So where the continents form and when they're breaking up has a lot to do with the CO2. The breakup of Pangea was thought to have consumed a lot of CO2 and started a trend towards cooling that kept going because of the albedo effect. The albedo is the amount of energy that's reflected back and you have something that's white, it reflects a lot more, it doesn't absorb the energy so that as we go into a cooling trend and we get more of sea ice, more snow we get an albedo that's very high in reflecting everything and that cools the planet which makes the albedo go up. So you can go into one of these trends that's triggered by weathering that was triggered by the breakup of a supercontinent that leads to a snowball event. So we had that big snowball event and we're still wondering about how it happened because how it relates to the Cambrian explosion of for instance starting to have evolution of life is something quite fascinating and then the other question of once you go into a snowball event how do you get out of it? And the obvious answer is you have to have volcanoes emitting lots of CO2 to get on a warming trend to head back the other way. Typically through our history we go through a cooling trend, a warming trend, a cooling trend like that and it's interesting to try to think about why and when it turns around and how it turns around and the supercontinent cycle is one piece of that puzzle.