Laser-based lidar tech is rewriting history — if climate change doesn't erase it first

Tashbulak and Tugunbulak may be largely forgotten today, but the pair of Uzbekistani cities thrived during the Medieval era. Nestled in the Tien Shan mountains, the largest east to west mountain range on Earth, merchants from all over Europe and Asia would travel to Tashbulak and Tugunbulak to hawk their wares. Located on the famous Silk Road, Tashbulak and Tugunbulak were a nexus of trade and culture.

More than a thousand years have passed since their heyday, however, and as humans continue to destroy our environment, archaeological treasures like those in these cities could be lost forever. But thanks to a powerful laser-based technology called lidar, ancient history is being illuminated like never before.

Scientists still debate whether lidar stands for “laser imaging, detection and ranging” or “light detection and ranging.” Either acronym accurately summarizes the technology, which uses lasers to measure large areas by targeting a surface or object and measuring how long it takes for light to be reflected back. But no one is debating how lidar is helping preserve humanity’s most important historic sites from our species’ tendency to destroy our natural environment.

When it came to the lost cities of Tashbulak and Tugunbulak, anthropologist Michael Frachetti used lidar to conduct unprecedentedly detailed scans of the Medieval metropolis, which thrived approximately 2,000 meters above sea level between the 6th and 11th centuries. Their research was published in October in the journal Nature, with Frachetti marveling at how these ancient cities struggled with the same self-destructive habit of exploiting their natural resources.

“There does appear to be an environmental factor which played a role in both the establishment of the cities in high altitude — in this case areas rich in ore and other resources,” Frachetti said. “We hypothesize that the investment these populations made in producing iron metallurgy would have had significant environmental impact on local forest resources used for fuel. This remains to be demonstrated scientifically, but given the scale of smelting documented at Tugunbulak, it makes sense that there would have been consequential effects on the ecology of this highland landscape.”

Frachetti, who teaches at Washington University in St. Louis, added that “we think there is a broader lesson related to the impact of intensive exploitation of the environment and the ultimate sustainability of urban settings, which we can extrapolate from this time in history.”

Lidar image of La Mojana Raised Fields in Colombia (Courtesy of NV5)Ron Chapple agrees that lidar keeps reminding us about the importance of environmental protection. Chapple is the former CEO of GEO1, a company that specialized in utilizing lidar technology. He was an early investor in lidar technology, recognizing during his former career as an aerial cinematographer that it has the potential to transform archaeology. He regularly is consulted by scholars about how to use lidar, and today Chapple is VP Global Strategic Solutions at NV5, a multinational corporation that also specializes in lidar, imaging and analytics.

He is particularly well-known for acquiring extremely detailed images of a lost city half a world away from Uzbekistan — Ciudad Perdida (literally Spanish for "lost city"), an ancient city in Colombia’s Sierra Nevada de Santa Marta mountains. Ciudad Perdida is believed to have been founded about 800 A.D., which if true would make it older than the ancient Peruvian city of Machu Picchu by more than six centuries. Archaeologists dream of discovering more locations like Ciudad Perdida, and yet Chapple has watched with anxiety as human activity endangers these delicate sites.

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Indeed, last week a 1,100-year-old pyramid in Mexico collapsed into a pile of rubble because of heavy rainfall that was preceded by record-breaking drought which evaporated entire lakes. Tariakuiri Alvarez, a living member of the P'urhépecha tribe, told Live Science his ancestors would have interpreted the crumbling of the pyramid at Ihuatzio as a "bad omen."

Salon spoke with Chapple about the future of lidar and how, because of climate change, he believes humanity needs to start using lidar as much as possible to protect our civilization’s most precious relics before they are lost forever.

This interview has been edited for clarity and length.

What do we know for sure about climate change and its impact on the future of archeology? What about other human activities such as warfare or various forms of industrial, agricultural and other commercial development?

I think it's safe to assume that climate change is going to change current human living patterns in a few different ways. For example, if the world is getting a little bit warmer where crops would say grow at a 2,000-foot elevation, now that it's warmer, the farmers might need to go upslope to 3,000-foot elevation and start clear-cutting areas so their crops can continue to grow. By clear-cutting, you have the potential to damage untouched areas where there could be sites of archeological significance.

I think [climate change] is one of the main ones, as well as any similar type of development where there are more people moving on Earth. If there is warfare, any human influence has the potential to expose untouched areas. If we can use lidar and survey those areas in advance, we not only may be able to preserve and record any evidence of ancient settlements, but that data could assist in better land planning.

Likewise with sea level rise [caused by climate change]. Increasing ocean heights may cause migration from the coasts to higher ground. Again, you're opening or removing forests with farming and development that could affect archeological sites.

How does lidar offer a solution to these?

We were doing archeological discovery in the Sierra Nevada de Santa Marta mountains in northern Colombia. During the helicopter flight, we could see clear-cutting occurring within a couple of miles of the site that we were surveying and in roughly similar terrain. Now we have no way of knowing if there was anything of historical value there or not, but it has the potential of modifying the land so that we may never know what history could have been hidden under the rainforest.

Lidar image of Ciudad Perdida (Courtesy of NV5)How much of the data that your company has accumulated over the years can be realistically analyzed by qualified historians, anthropologists and other scholars who can actually transform it into meaningful stories and history?

NV5 doesn’t deliver just numbers. NV5 believes in democratizing data, and we use algorithms that say, for archeologists, will highlight the contours of the ground. This visualization makes it easier for researchers to be able to look at that data and understand what they're looking at. In many cases, we are layering that data with other information such as imagery from either airplanes or satellites to provide more context.

Aerial View of Ciudad Perdida (Courtesy of NV5)How do you tell a story with that data? How do you make that data easy to understand? All of the storytelling takes time, and time is critical right now. We analyze and learn what's out there. I think of Chris Fisher, an archeologist friend of mine who discovered ancient settlements in Honduras using lidar technology. Chris always says, “Is the Amazon natural,  or are we looking at an overgrown garden?

In the 1500s, something like 90% of the population in South America was wiped out because of diseases that came in when the Europeans settled and started to explore. For example, in 1520, when [Hernán] Cortés arrived in the densely populated Mexican city of Tenochtitlan, his soldiers brought along smallpox, which killed off 40% of the population in a single year. It harkens back to COVID-19 in an extreme sense. The more we learn about these civilizations that are now beneath the dense jungle canopy, the more we may be able to learn about our future.

I'm thinking of the recent discoveries in Brazil and Uzbekistan using lidar. As I'm sure you saw, a research team in the Brazilian state of Rondônia discovered an 18th century Portuguese colonial city. In Uzbekistan, a different research team provided great detail about a pair of 6th to 11th century cities on the Silk Road, Tashbulak and Tugunbulak, that had thrived before being lost to time. What are your thoughts about the significance of these individual discoveries and how the average news consumer should internalize them in terms of their larger relevance?

Is there something out there that's going to change our civilization dramatically? Maybe not today, because we have better ways to fight disease, but knowing what was out there is essential. Is it possible that some of the world’s greatest cities are still lying hidden beneath the Amazon rainforest, or in other undiscovered areas around our world? While I am not a doomsayer, with a catastrophic meteor or nuclear event, large swaths of civilization could be changed forever.

What’s interesting to me about working with NV5 is that we provide data and analytics that will provide the tools for humanity to manage climate change and population growth. But back to archeology, we need to understand what was there before it's too late and provide the history that our fellow humans and children deserve.