WEBVTT - Did the Maya Civilization Fall Because of Climate Change? 0:00:01.840 --> 0:00:08.480 Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Louren Boglebaum. 0:00:08.480 --> 0:00:14.080 Here Back in nineteen twenty nine, Colonel Charles Lindbergh, the 0:00:14.120 --> 0:00:17.280 same aviator who two years before had become famous by 0:00:17.360 --> 0:00:20.880 flying solo across the Atlantic Ocean, was flying a Pan 0:00:20.880 --> 0:00:24.560 American Airways plane from Miami to Panama when he decided 0:00:24.560 --> 0:00:28.320 to do a little sight seeing over what's now Belize. 0:00:28.440 --> 0:00:31.520 Lindberg veered inland and flew over a stretch of southern 0:00:31.520 --> 0:00:35.120 Mexico and Central America that was covered with dense vegetation, 0:00:35.720 --> 0:00:39.920 a region so remote and inaccessible that outsiders reportedly had 0:00:40.000 --> 0:00:45.000 never ventured there. As Lindberg soared over the trees, something 0:00:45.040 --> 0:00:48.760 ahead caught his attention, what an Associated Press account later 0:00:48.800 --> 0:00:52.120 described as two emerald eyes staring up at him out 0:00:52.120 --> 0:00:56.480 of the tangle of the jungle brush. As Lindberg swooped 0:00:56.480 --> 0:00:59.680 in low to investigate, he was astonished. It was the 0:00:59.760 --> 0:01:03.520 ruins of a vine enshrouded city about eight miles across 0:01:03.600 --> 0:01:08.120 that's about thirteen kilometers, dotted with numerous small periods, and 0:01:08.200 --> 0:01:10.759 what turned out to be a stone temple two hundred 0:01:10.800 --> 0:01:14.240 and fifty feet tall that seventy five meters with twin 0:01:14.319 --> 0:01:17.920 reflecting pools, the green reflections from which had looked to 0:01:18.000 --> 0:01:20.959 him like a pair of eyes, But there were no 0:01:21.080 --> 0:01:24.840 signs of humanity anywhere around the site. E Lindberg was 0:01:24.880 --> 0:01:28.080 filled with awe as he gazed upon the ruined grandeur 0:01:28.280 --> 0:01:31.680 of a once mighty Maya city whose builders apparently had 0:01:31.720 --> 0:01:37.640 abandoned it to be swallowed by the jungle. But why, 0:01:38.760 --> 0:01:42.680 That's a question that archaeologists, scientists, and historians have been 0:01:42.720 --> 0:01:47.200 puzzling about ever since. During its heyday, what's called the 0:01:47.200 --> 0:01:50.640 Classic Maya Civilization, which blasted from about two hundred and 0:01:50.640 --> 0:01:54.240 fifty to nine hundred CE, the Maya peoples had one 0:01:54.240 --> 0:01:57.440 of the most advanced and complex civilizations on the planet. 0:01:58.400 --> 0:02:01.440 They built more than forty network worked, yet independently run 0:02:01.480 --> 0:02:05.320 cities across what's now Central America and Mexico, filled with 0:02:05.480 --> 0:02:09.839 temples and palaces and elaborate sculpture and carvings whose magnificence 0:02:09.880 --> 0:02:14.680 still impresses. They developed advanced irrigation techniques for growing crops, 0:02:14.840 --> 0:02:19.040 and performed astronomical observations that enabled them to predict solar eclipses. 0:02:19.960 --> 0:02:22.680 They had a family of around thirty languages that included 0:02:22.720 --> 0:02:25.960 written hieroglyphs, which some Maya used to write books on 0:02:26.040 --> 0:02:29.919 paper made from fig trees. They devised an elaborate calendar 0:02:30.120 --> 0:02:35.400 whose cycles ran for centuries into the future. And yet 0:02:35.600 --> 0:02:38.680 by the time Spanish conquerors arrived in Central America in 0:02:38.720 --> 0:02:41.800 the early fifteen hundreds, many of the Great Maya cities 0:02:41.840 --> 0:02:45.200 were empty, and the builder's descendants had integrated into other 0:02:45.240 --> 0:02:49.480 communities or cultures, or returned to smaller communities with smaller 0:02:49.520 --> 0:02:54.679 scale architecture. We should note that the entire civilization did 0:02:54.720 --> 0:02:58.280 not collapse. No civilization at that large of a scale 0:02:58.280 --> 0:03:00.840 as a monolith, and the fact that there are Maya 0:03:00.880 --> 0:03:05.240 peoples living today attests that the entire population didn't just vanish, 0:03:05.880 --> 0:03:10.160 but several large urban centers were all abandoned between around 0:03:10.240 --> 0:03:16.519 eight hundred to nine hundred CE. Over the years, scholars 0:03:16.560 --> 0:03:19.919 have developed numerous theories about why the mighty Classic Maya 0:03:19.919 --> 0:03:23.919 civilization went through this fall, but recent discoveries point to 0:03:23.960 --> 0:03:28.480 a cluster of causes that sounds eerily familiar, one centered 0:03:28.600 --> 0:03:33.720 on climate change. Oh, we are lucky that at least 0:03:33.720 --> 0:03:36.800 some of the Classic Maya's written records survived, and that 0:03:36.840 --> 0:03:39.680 they were also written about by post classic Maya peoples. 0:03:40.040 --> 0:03:43.160 That some of those records survived, which has enabled scholars 0:03:43.200 --> 0:03:47.839 to partially reconstruct their history. But in some ways, those 0:03:47.920 --> 0:03:51.080 tenalizing clues have only made the mystery of the decline 0:03:51.240 --> 0:03:56.120 more frustrating. Over the years, researchers have developed various theories 0:03:56.200 --> 0:03:59.360 about what caused the decline of those Maya cities, though 0:03:59.360 --> 0:04:02.160 it was most likely a combination of these and other 0:04:02.240 --> 0:04:05.880 factors and not anyone alone. Here are a few of 0:04:05.920 --> 0:04:10.320 the most prominent theories, in no particular order. First, we 0:04:10.440 --> 0:04:14.480 have over farming. Some scholars have argued that my society 0:04:14.560 --> 0:04:17.960 grew too rapidly for its own good. As the population 0:04:18.080 --> 0:04:21.360 of some cities increased, it put vocal farmers under more 0:04:21.400 --> 0:04:24.440 and more pressure to grow food, and gradually they ran 0:04:24.480 --> 0:04:27.840 out of fresh forest land. Clear that would have forced 0:04:27.880 --> 0:04:30.360 them to plant crops in their fields without an adequate 0:04:30.440 --> 0:04:33.520 fallow cycle, that is the time it takes soil to 0:04:33.640 --> 0:04:38.440 rebuild its nutrients supply. Deforestation like that can also disrupt 0:04:38.440 --> 0:04:43.880 the water supply by rerooting rainwater and groundwater. A Second, 0:04:44.040 --> 0:04:49.119 we have interior and exterior political turmoil. Each Maya city 0:04:49.160 --> 0:04:52.640 state had its own rulers who often had their populations 0:04:52.680 --> 0:04:55.760 convinced that they had ties with deities and were powerful 0:04:55.839 --> 0:04:59.040 enough to control the weather. Hard to say whether or 0:04:59.080 --> 0:05:04.040 not those leaders believed in those magical powers themselves. Their 0:05:04.040 --> 0:05:07.440 efforts to conquer neighboring cities and peoples may have backfired, 0:05:07.640 --> 0:05:11.680 as long periods of war sapped resources been led to retaliation. 0:05:12.560 --> 0:05:15.040 There's evidence that a number of Maya cities eventually were 0:05:15.080 --> 0:05:21.520 besieged and fell to invaders. Third, we have disease, though 0:05:21.600 --> 0:05:24.479 in this case the theory is about an agricultural epidemic, 0:05:24.640 --> 0:05:27.560 not a human one. A maze was a staple crop 0:05:27.680 --> 0:05:31.400 across the Maya civilization, and the Maze mosaic virus may 0:05:31.440 --> 0:05:36.400 have destroyed much of their food supply. A note that 0:05:36.440 --> 0:05:39.480 all three of these factors are connected to the fourth theory, 0:05:40.040 --> 0:05:43.800 the aforementioned climate change. A destruction of the food and 0:05:43.839 --> 0:05:48.479 water supply by overfarming, deforestation, warfare, and disease would have 0:05:48.520 --> 0:05:53.360 been exacerbated by the happenstance of natural climate change. Add 0:05:53.400 --> 0:05:55.920 to this the fact that political leaders were supposed to 0:05:56.000 --> 0:06:00.520 be able to control the weather. Anthropologists say this chain 0:06:00.600 --> 0:06:03.600 of unfortunate events would have caused the people to deeply 0:06:03.680 --> 0:06:07.159 lose trust in their leaders, which would in turn further 0:06:07.200 --> 0:06:12.200 disrupt agriculture and infrastructure and trade, everything that ties the 0:06:12.200 --> 0:06:17.960 city together. A while our modern civilization is driving global 0:06:17.960 --> 0:06:21.800 warming by polluting the atmosphere, the Earth's climate is affected 0:06:21.839 --> 0:06:25.800 by other factors, such as changes in solar activity and volcanoes. 0:06:26.680 --> 0:06:29.200 The plight of the Maya seems to be largely the 0:06:29.240 --> 0:06:34.120 result of such natural cycles. Scientists who have studied mineral 0:06:34.120 --> 0:06:37.359 deposits left by dripping water in caves have been able 0:06:37.360 --> 0:06:40.039 to construct a two thousand year long history of weather 0:06:40.080 --> 0:06:44.279 patterns in Central America. In an article published in Science 0:06:44.360 --> 0:06:47.400 back in twenty twelve, the researchers revealed that for the 0:06:47.400 --> 0:06:51.560 first several hundred years of classic Maya civilization, they benefited 0:06:51.600 --> 0:06:54.479 from unusually wet weather that made it easier to grow 0:06:54.480 --> 0:06:58.880 crops and enabled the population to expand. That also made 0:06:58.920 --> 0:07:01.799 the Maya kings look pretty good because they could claim 0:07:01.839 --> 0:07:04.480 credit for conducting the rituals that kept the rains coming. 0:07:06.080 --> 0:07:10.240 But around sixteen sixty CE, the weather changed and rain 0:07:10.360 --> 0:07:14.440 became more infrequent in some regions of the area. The 0:07:14.520 --> 0:07:17.880 Maya also may have accelerated that climate change by cutting 0:07:17.880 --> 0:07:21.480 down the forest around them, probably for fuel and create 0:07:21.520 --> 0:07:24.240 wood plaster for use in their ornate buildings and to 0:07:24.400 --> 0:07:28.960 clear land. From studying pollen found in ancient layers of 0:07:29.000 --> 0:07:33.320 Central American lake sediment, scientists learned that around eight hundred CE, 0:07:33.720 --> 0:07:37.720 tree pollen disappeared almost completely and was replaced by pollen 0:07:37.800 --> 0:07:42.120 from weeds. That suggests that the region's forests had all 0:07:42.120 --> 0:07:47.920 but disappeared. Without trees and their root systems to keep 0:07:47.960 --> 0:07:51.800 soil in place, erosion would have worsened, carrying away fertile 0:07:51.840 --> 0:07:56.240 top soil, which would have crippled local agriculture. Additionally, trees 0:07:56.280 --> 0:07:59.640 function as natural air conditioners, a drawing water through their 0:07:59.720 --> 0:08:03.160 leaves in cooling the surrounding air. When the water evaporates, 0:08:03.680 --> 0:08:05.720 you can experience the same effect if you live in 0:08:05.720 --> 0:08:08.680 a city. In a park with trees, it's going to 0:08:08.720 --> 0:08:11.400 seem cooler than it does out on a city block 0:08:11.440 --> 0:08:16.120 with just buildings an asphalt all around you. Computer simulations 0:08:16.160 --> 0:08:19.480 indicate that some regions temperature could have increased by as 0:08:19.560 --> 0:08:22.160 much as six degrees fahrenheit or around three and a 0:08:22.200 --> 0:08:26.280 half degrees celsius. That change would have been enough to 0:08:26.320 --> 0:08:30.200 alter the weather even more. Researchers who have analyzed changes 0:08:30.240 --> 0:08:32.880 in river sediment have found that in the century after 0:08:33.000 --> 0:08:37.360 deforestation in some regions, a rainfall declined there, with intense 0:08:37.559 --> 0:08:40.600 multi year droughts occurring around the years eight ten, eight 0:08:40.720 --> 0:08:46.400 sixty and nine ten CE. Because the people in these 0:08:46.400 --> 0:08:50.440 cities probably depended upon rain captured in reservoirs for drinking water, 0:08:50.720 --> 0:08:53.560 they would have faced not only hunger, but thirst as well. 0:08:54.360 --> 0:08:57.680 It's not hard to imagine how a panicked population would 0:08:57.679 --> 0:09:00.760 have fled its once great city their way of life 0:09:00.840 --> 0:09:05.040 collapsed into a sort of pre Columbian mad max. Though 0:09:05.200 --> 0:09:08.920 again the note that Classic Maya civilization was not a monolith. 0:09:09.559 --> 0:09:13.000 Different communities faced slightly different pressures and came up with 0:09:13.000 --> 0:09:18.959 different solutions. As some cities fell, others prospered. That said, 0:09:19.160 --> 0:09:22.040 there are some lessons from the so called collapse of 0:09:22.080 --> 0:09:25.120 the Classic Maya that we ignore at our own peril. 0:09:26.040 --> 0:09:28.800 Scientists warn that we are repeating the same pattern of 0:09:28.840 --> 0:09:32.640 deforestation that may have exacerbated climate change in Central America 0:09:32.679 --> 0:09:36.040 a millennium ago, except on a far more massive scale. 0:09:37.080 --> 0:09:39.920 Trees are about fifty percent carbon, and in the US 0:09:39.960 --> 0:09:43.160 alone they presently absorb or sinc a little less than 0:09:43.200 --> 0:09:47.160 a million metric tons of atmosphere warming carbon dioxide, which 0:09:47.360 --> 0:09:50.720 offsets between ten and twenty percent of what Americans spew 0:09:50.760 --> 0:09:54.520 into the atmosphere by burning coal and gasoline. But when 0:09:54.559 --> 0:09:57.280 we cut down trees or burn them, they released their 0:09:57.280 --> 0:10:00.640 stored carbon into the atmosphere, and they aren't around to 0:10:00.720 --> 0:10:04.439 absorb any more of it. Over the past several centuries, 0:10:04.559 --> 0:10:07.240 the US has cut down about ninety percent of the 0:10:07.280 --> 0:10:10.800 forests that once covered the continent, and what still remains 0:10:11.000 --> 0:10:15.200 is in peril and in currently developing nations, once lush 0:10:15.280 --> 0:10:19.480 forests have been disappearing at an alarming rate thanks to logging, agriculture, 0:10:19.600 --> 0:10:23.559 and the need for human living space. In recent years, 0:10:23.559 --> 0:10:26.400 there has been some international progress in slowing the rate 0:10:26.400 --> 0:10:29.560 of deforestation, but we still face the risk that it 0:10:29.559 --> 0:10:33.640 will push us even faster into climate chaos. It's a 0:10:33.679 --> 0:10:36.640 problem that we must work harder to solve, both as 0:10:36.679 --> 0:10:41.880 a broad civilization than within our own differing communities. Personal 0:10:41.960 --> 0:10:44.560 choices feel small, but they do add up, and you 0:10:44.600 --> 0:10:46.680 can make your voice heard in your local government on 0:10:46.720 --> 0:10:51.319 bigger issues. If you're here, you probably agree that learning 0:10:51.400 --> 0:10:53.760 is the fun part, So learn what you can do 0:10:53.920 --> 0:10:57.080 by checking out your government agencies in the US that's 0:10:57.120 --> 0:11:00.559 going to be at EPA dot gov, and what local 0:11:00.600 --> 0:11:07.959 activists are up to. Today's episode is based on the 0:11:08.040 --> 0:11:11.079 article did the Maya civilization end because of climate change? 0:11:11.120 --> 0:11:13.680 On how stuffworks dot com written by Patrick J. Kiger. 0:11:14.160 --> 0:11:16.520 Brain Stuff is production of by Heart Radio in partnership 0:11:16.520 --> 0:11:19.000 with how stuffworks dot Com and is produced by Tyler Klang. 0:11:19.559 --> 0:11:22.640 Four more podcasts my heart Radio, visit the iHeartRadio app, 0:11:22.720 --> 0:11:25.600 Apple Podcasts, or wherever you listen to your favorite shows.