 This beautiful sculpture commemorates a naval battle between the Khmer and Champa empires. You might start to get nervous and check over your shoulder if you were looking at it in real life, as there are clearly some soldiers being eaten by local fauna. But the crocodiles tend to stay away from heavily populated areas. That's relief. In Cambodia, the area surrounding the ancient capital city of Angkor is littered with more than a thousand stone temples dedicated to both Hindu and Buddhist worship. The largest of which, Angkor Wat, is featured prominently on the country's flag. It's the biggest religious structure in the world, over one and a half million square meters in size, more stone than the pyramids at Giza, and everywhere you look, its massive pillars, walls, and doorways have been carved into impressively florid depictions of religious and historic figures. Many of the structures have collapsed, been buried, or overtaken by the encroaching jungle. But the locals who have lived in and around the temples since before UNESCO declared them a World Heritage Site, the Khmer, maintained that their ancestors never abandoned them. That despite the historic ups and downs of their people over the past 1200 years, the temples have always been part of their culture. It can be hard to imagine everything that has to work for a pre-industrial society to create these imposing structures, or how it might stop working. In episode 208, we described Richard Cook's model of how complex systems fail. A common metaphor asks us to imagine the layers of defense as slices of Swiss cheese. Stay with me here, where each individual layer will have a few holes, but failure only occurs when you have enough holes in enough slices, aligning at the same moment to reveal a clear path through those defenses, allowing the system to be damaged. Think of two-factor authentication. Your username and password might be hacked, your phone's text messages might be intercepted, but you're only in trouble if both happen at the same time. If you examine the history of societies like the former Khmer Empire, it's hard not to see parallels to the Swiss cheese model. Empires don't fall apart instantly whenever something goes wrong. They can usually lean on systems with extra capacity to cover for ones that are temporarily compromised. The army isn't strong enough to repel invaders on its own, so agricultural surplus is used to hire mercenaries. Some folks embrace a new-fangled Buddhist religion, but rather than fracturing the community along spiritual lines, previously unadorned walls of temples are repurposed with new deities, turning them into unifying, multi-denominational places of worship. Redundancy, surplus, accommodation, flexibility, and backups for the backups allowed the Khmer Empire to maintain and reproduce itself for centuries through all sorts of challenges, failures, and disasters. When the end came, it was not a dramatic third act climax, with barbarians sacking the capital or the toppling of columns. It was simply a long series of small setbacks in a hundred different places over hundreds of years, each of which eliminated one more set of tools for dealing with the other problems. Drought hampered food production. Plague limited manpower. Political infighting undercut faith in governance. Each event tied yet another hand behind the Khmer's backs. As these obstacles mounted, the people did what people always do to survive. They adapted. Some temples were deliberately toppled by locals ransacking them for building materials, or scavenging for tasty temple-dwelling critters. Others raided the structures for ornamental statues and other treasures to trade away to foreigners. No individual act was the one that ended the Khmer Empire, but at the conclusion of the 13th century, there were many beautiful stone ruins surrounded and inhabited by people who may have had a cultural, genealogical, and historic connection to them, but couldn't imagine building any themselves. I think summarizing that centuries-long fragmented story under a tidy name like The Fall of the Khmer Empire is a sort of coping mechanism. The truth is, there's no rubric or historic event horizon that separates the empire at the height of its power from modern-day Cambodia. Similarly, nobody actually witnessed anything like The Fall of Rome. No one stumbled into a big switch that said pyramids on one side and no pyramids on the other. In each case, these changes were precipitated by small, infrequent shifts and priorities that eventually made it slightly less pressing for the locals to keep some giant stone monuments in good condition. Time passed. Activities that were routine slowly became impractical or frivolous under new circumstances as people adapted to having fewer and fewer options. One day, dragging a 200-kilogram sandstone block 40 kilometers by elephant was unremarkable. The next day, it just didn't really seem like it was worth the effort. Maybe we'll take care of it tomorrow. Maybe it can wait until next year. Maybe never again. There's no way of knowing when a brief hiatus is actually a permanent one, and unless you want to drive yourself insane every time you see a pothole or read about a chip shortage, it's nice to imagine that there's some bright line separating the small interruptions from the big ones. Historians know better than anyone that calling that long series of unfortunate events the collapse is more about our desire for a tidy story than anything else. If any of a large chain of environmental or political contingencies had broken some other way, if the Khmer had caught a single lucky break or had slightly more room to maneuver, those temples might have been maintained in good condition until the present day. Speaking of the present day, most tourists try to get to anchor what pretty early, both to see the famous sunrise over the 65-meter godbedeck towers and to avoid the uncomfortable, sometimes hazardous heat that beats down later in the day. Thankfully, there was some cloud cover while I was visiting, so the hi was only 104 Fahrenheit or 40 degrees Celsius, a few degrees shy of the historic record there. The IPCC projects that Cambodians can expect temperatures to continue rising, bringing worse floods in wet seasons, droughts in dry seasons, and making it increasingly dangerous for the half of its population working in agriculture to do manual labor outside. The climate will also be an obstacle for the restoration efforts many countries are funding in and around Angkor, limiting how many hours their archaeological teams can spend each day carefully digging up and reassembling those beautifully carved blocks of stone. Fighting the slow-motion train crash of climate change can feel overwhelming. The institutions and cultural practices built around extracting, selling, and burning fossil fuels are, if you'll forgive me, well-oiled machines, and it often seems like they're casually rolling over any resistance. But while we shouldn't lose sight of a 100% sustainable future, we are not failing just because we haven't stopped them dead in their tracks. As with Cook's model of complex system failure, there's no grand singular change that could have guaranteed our future safety, even in principle. The only thing we could ever do was play the odds, shore up weaker failing systems, develop contingency plans and backups to keep vital processes running even if they take a hit. Anything to give future us the greatest number of options and as much time to exercise them as we can manage. Hoping we'll have enough cheese slices at any given time to keep things together. Even the smallest of victories, like delaying new oil infrastructure for a week or so with protests, gives us one more roll of the dice to find some way to adapt gracefully. Many of the Angkor temples are dedicated to the gods Brahma, Vishnu and Shiva, often taken to represent the acts of creation, maintenance, and destruction. Some Hindus assert that every entity in the universe contains all three processes simultaneously, existing in a continuous state of becoming, of persisting, and of ending. There's something in that to meditate on. Thank you very much for watching. And thank you for being so patient while I got this episode out. As you can see, I took a little vacation and also it's been pretty hectic around here as I pack up my apartment. Don't forget to blah, blah, subscribe, blah, share. And don't stop thunking.