1 200 Year Old Clue To Why The Mayan Civilisation Disappeared BBC Timestamp BBC Studios

If we walked outside right now, we'd be able to tell that it was cloudy, we would be able to tell that it was cool, and that there wasn't a great deal of wind. But we wouldn't know about the greenhouse gas content, we wouldn't know if it was stormy out in the oceans. We wouldn't be able to tell as richly what we can tell from the ice core record going back through time. And that's a pretty odd thought when you think about it. We've captured something that's almost better at telling us about the past than we're able to tell by going out and sniffing the air outside. Paul has constructed a uniquely accurate history of global weather from his ice cores. When he heard about Dick's drought theory, he decided to check his cores for the 9th century. Would he be able to find any evidence of dramatic climate change in the Northern Hemisphere? The first thing that we looked at was our record of ammonium. And ammonium is a chemical that gets up into the atmosphere, which tells us whether or not there was a lot of vegetation in the Northern Hemisphere. If there's a lot of vegetation, one assumes it was probably warm and wet. Low amounts that it was probably drought conditions, that there weren't a lot of plants, the soils had probably dried up. And when he looked at the ice that was 1,200 years old, he was astonished. We found that there was a tremendous drop in ammonium. They, in fact, had probably not experienced a drought like this going back to maybe 3,000 years. So the ice cores confirmed Dick's hunch. At exactly the time of the Maya collapse, it was dry and cold across the Northern Hemisphere. The very conditions that would indicate drought in the Maya areas. But archaeologists remained unconvinced. If there had been such a severe drought, why was there no record of it in the Maya's own chronicles? The Maya carvings tell of great battles, of ruling dynasties and all-powerful gods. But on drought, they are silent. I decided to see whether the Maya had written anything about drought. We don't find anything on their monuments and buildings. But I thought that if drought were a regular part of Maya life, that they must have written about it somewhere. Then he had a stroke of luck. He came across this rare manuscript written by the Maya. One of the few that had not been destroyed by the Spaniards. So I came to this Maya book to see whether there was any discussion of drought. And right here on the last page, there it is. There is a hieroglyphic symbol for drought. They did write about drought. It was an ongoing part of their life. And there it is, right there.