“How can you live here?”

Narrow valleys, mighty rivers, deep snow, and a harsh climate: For over 600 years, the people in the Tea Horse Road area in the mountainous highlands of southeast Tibet have come to terms with their region being regularly afflicted by flooding and landslides. They have learned to cope with these natural hazards. This is valuable knowledge in times of climate change, in which many regions of the world are confronted with extreme weather events, torrential rainfall, and flooding — and with the strength and frequency of these occurrences constantly increasing.

Liang Emlyn Yang has undertaken to collect this treasure trove of knowledge. The Munich-based geographer from the “Human-Environment Relations” Research and Teaching Unit at LMU studies the consequences of climate change. Now he has chosen a rather different perspective from which to analyze the problem. At the heart of his research is not the question as to the negative effects of global warming, the vulnerability of societies, the risks and the losses. Instead, he is focusing on the ability of people to cope with change. He is looking at the social resilience of a population that lives in regions threatened in this way – in flood plains, on riverbanks, in coastal zones. How have societies there managed to survive, develop, and grow — despite the recurring destructive natural disasters? And what lessons can we learn for the future from these areas?

Emlyn Yang wants to explore these questions over the coming years with his STORIES project, which has been awarded a Starting Grant from the European Research Council. He will seek to discover how climate adaptation can work from the perspective of resilience – using the example of the Tea Horse Road. This area derives its curious name from its situation along an historically important trade route between the Chinese provinces Yunnan and Sichuan, Tibet and further west to India. For over 2,000 kilometers, the route passes through mountainous terrain, traversing high passes and mighty rivers. Traditionally, tea bricks were traded for horses here. The long settlement history of this mountainous region in the southeast of the Tibetan Plateau is particularly well documented and offers highly detailed insight into the past. This wealth of documentary evidence allows us to trace which natural hazards the population has had to contend with for centuries right down to the present day — and how they successfully mastered these challenges.

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An ideal ‘natural laboratory’

“In recent years, I’ve already done research in Tea Horse Road area, as well as in Vietnam and Thailand. This has shown me that people have developed many strategies over time to allow them to settle in flood plains.” This includes the construction of dams, reservoirs, and weirs, but also building more stable houses. “Little changes were often enough – such as building the ground floor level a little higher up.”

This is just one example, says Yang, of the adaptations that have enabled people over the past centuries not just to settle in the secure uplands, but also to establish new settlements in valleys threatened by flooding. The scientist has observed that many of these societies are not only surviving but actually growing. People are consciously deciding therefore to live in regions at risk of flooding and are able to cope with this threat. In his project STORIES, Yang wants to discover how this resilience came about.

The Tea Horse Road has always been affected by flooding and landslides; the environmental history of the region going back 600 years is so well documented that it can be traced back at the level of cities and communities, even at the level of households. For Yang, this makes it an ideal ‘natural laboratory’ for the systematic analysis of social resilience across time and space. “If you only look at a single flood event, you get a very narrow picture of human resilience.” However, if you observe flooding and landslides over a longer period, you gain an idea of how the affected societies make progress in managing such natural catastrophes.

But how can resilience be made measurable and comparable? How can it be quantified? “The resilience of a human society is made up of many different components,” says Yang. Aspects such as governance, technological development, social structure, and culture are very important. In addition to population density, indicators include things like the volumes of traffic and trade, the density of the road network, and the existence of flood control measures and emergency care planning. By means of a so-called index system, the researchers are able to assign values to such indicators and thus mathematically quantify resilience — a prerequisite for comparisons across space and time.

Emlyn Yang and his team evaluate documents from historical archives and scientific literature. They are helped here by the relatively good records kept by the Chinese central government following the conquering of the region by the Ming dynasty in the second half of the 14th century. To be able to rule in the new province, the government in far-off central China needed to know what was going on locally. So they recorded how many people lived in the regions, what resources the land offered, what crops could be grown there, and what natural hazards there were. The investigations by the Chinese officials continue to provide valuable information to researchers today.

On top of this, there are the reports in which the local government in the Tea Horse Road area informed central government over the following centuries about flood events and other natural disasters such as landslides and earthquakes. These reports usually listed damage and prevention measures in meticulous detail, as part of their purpose was to seek financial assistance from the government or abatement of taxation. “To receive financial aid from Beijing for rebuilding, they needed to precisely itemize how many people had died or how many houses and streets had been destroyed,” says Emlyn Yang.

Collecting data since the Ming dynasty

Major flood events in the history of the Tea Horse Road area are particularly interesting subjects for evaluation. But well preserved documents are not available in the same quantities from every year, and only a small portion of writings and historical maps have been digitized. For the researchers, this means a lot of work in archives and libraries on site. As such, Emlyn Yang will make repeated multi-week trips to the Tea Horse Road areas with his team of postdocs and doctoral candidates over the coming years in order to gather data. “In addition to studying the historical events, we will also look at the current situation and ask the local population about their experiences of the flooding of recent years,” says Yang. “When we compare the data from the past with today’s data, we will be able to see how the resilience of people on site has developed.”

It remains to be clarified whether such findings from the Tea Horse Road area are transferable to other flood-threatened regions of the world. Emlyn Yang hopes to find patterns, which he would like to compare with data from the Mekong Delta in Vietnam. This would eventually yield insights into how to develop models for other regions, such as flood risk areas in Europe.

According to Yang, the trend of resilience generally increasing over time in regions exposed to greater natural risks is also apparent in Europe: In the Netherlands, for example, people have long adapted to the dangers of the coast through suitable infrastructure, dams, dikes, and early warning systems. Moreover, the higher the standard of living and the better the economic situation, the more it becomes possible to invest in protective measures against natural hazards. “Human societies have made great progress over time when it comes to dealing with floods – that is to say, their resilience has grown.” This is often forgotten in discussions about the consequences of climate change. “Not everything will just get worse and we should retain an optimistic, constructive perspective on the subject of flooding and flood protection.”

In view of the threat from flooding and landslides, technical solutions such as dams and flood-proof building designs are not the complete answer. Mental resilience is also vitally important. “Routinely, I would ask people: Why do you live here? Indeed why have you chosen to move here and build houses here?” Emlyn Yang observed many parallels in this regard in the various regions threatened by flooding – everywhere, the mental ability to live with risk plays a major role. People must be able not only to cope with the damage, but also with the threat.

“The crucial question for me is: What can we learn from the history of the Tea Horse Road area in order to deal with the consequences of climate change now and in the future?” Understanding how people managed in the past to live with flooding, Yang is certain, can provide valuable indications for people today. In many regions of the world, climate change damage can no longer be prevented. “We need to think here and now about how we can adapt – and how we can live better with change.”

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Dr. Liang Emlyn Yang is a scientist at the “Human-Environment Relations” Research and Teaching Unit in the Department of Geography at LMU. In early 2022, the European Research Council awarded him a Starting Grant.

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