Jason Palmer, Nncholas Evans, Central America discussed on The Science Hour

The Science Hour
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There's a, there's a line at the end that says, given given what's out there in various exit planets, picking a blueberry is actually a fairly reasonable sort of thing to cheese. I, I'd like to see the calculation on. Okay. Well, I'm sure he'll come out with another paper. It sounds like this blueberry earth work to be done. Thanks, Jason. You're listening to the science side from the BBC with Mony Chesterton still to come. We ask, what's the point of curiosity? We uncover the alarming rise in unregulated and downright dangerous cosmetic surgery in Columbia, it another what they say, they will be killed, but us also get that was several bottles full of a greasy liquid. I didn't know what it was. She just started to inject me. It was painful, really painful. A started to call uncontrollably and the next day I lost consciousness and funding. I've done it. If you've got a smartphone, odds are you've done it to a new research, looks at the impact of the people. We've fob joining me to explain what funding is, is science our guest, Jason Palmer from the economist. Hello. Oh, sorry. I was. I was funding high, right? We're going to leave you. Guessing what funding is for now, because I which traveling across the world to Central America and back in time who doesn't love a story of lost civilizations. What were they like? How did they live and why did they disappear? The Maya civilization thrived the two thousand years in Central America and then collapsed in a relatively short period of time just before Spanish colonists arrived in the middle ages, the collapse is often held up as an example of the dangers of climate change the crisis being blamed for the prolonged drought, a thousand or so years ago. But the truth is harder to pin down paleo climatologist. NNcholas Evans, from the university of Cambridge has been revisiting the evidence because as he explains to roll impedes, we can learn from it today. So I think draws offense of major relevance today. So although the Maya civilization and today have no direct parallels. Of course, today we have GM crops. We have drought resistant plants and the distribution of water today is very. Different as it was in the my times and my were dependent on local water resources, local groundwater thera-, indirect lessons that we can learn about water, scarcity, and society. It's fundamental to our way of living and without water. I feel that all society would be really at risk. The problem with water is it runs away in evaporates. So how do you tell in the two thousand eighteen what was happening to water a thousand years ago, we've developed a new method to assess the changes in rainfall and relative administering at the time of the mind decline. And the way we did this was by analyzing sediment core taken from a lake in the Yucatan peninsula southern Mexico. This sediment core contains mud's, but importantly, also contains a mineral known as gypsum now gypsum forms during periods of drought when the lake level was lowered, and these gypsum layers have been correlated to the same time as the my decline. Now we've developed a new method that examines the war. Water that gets trapped within the chemical structure of gypsum when it forms. So all the water is actually disappeared. You have these little traces. Absolutely. So the lake level is only lowered. It doesn't dedicate and say the water gets trapped within the structure almost acting like fossil water of the past, and we can compare that water to the late today and you medically model the differences in climate conditions. How do you actually correlate the amounts of rainfall though a thousand years ago from just finding droplets of water in these gypsum crystals. So gypsum contains twenty point, nine percent water by weight and water itself is composed of oxygen and hydrogen and the oxygen and hydrogen isotopes tell us about the climate conditions of the past. So these are the sort of nuclear variances. It were of the atom, absolutely. Say hydrogen is composed of two isotopes h one and h two. An oxygen is composed of three isotopes oxygen, sixteen seventeen, and eighteen different masses mean that when the water evaporates, the lighter mass is preferentially lost from the lake basin. So jarring. Of drought, but lake water becomes residually enriched in the heavier isotope, do your results bear out the idea that there was a prolonged drought that really not the civilized sation for six absolutely say. We find that rainfall amount decreased by around fifty percent or half competitive today over multi Cadle droughts..

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