A Scientist's Life: Jade d'Alpoim Guedes

Jade d’Alpoim Guedes is an archaeologist at Scripps Institution of Oceanography and the Department of Anthropology at the University of California San Diego. She received a master’s degree in art history and archaeology from Sorbonne IV in Paris in 2009 and a PhD in anthropology from Harvard University in 2013. She joined UC San Diego in 2018.

explorations now: What do you do for a living?

Jade d’Alpoim Guedes: I'm an archaeologist at Scripps Institution of Oceanography and the Department of Anthropology at the University of California San Diego. I work on some of the parts of the world that are the most sensitive to climate change, which are high-latitude and high-altitude environments. We know that these areas of the world are a lot more sensitive to changes in temperature than lower-altitude or -latitude environments.

One of the areas that I work in is the Tibetan Plateau. The livelihoods Tibetans developed there that are based on farming and pastoralism are some of the most threatened by recent changes in climate. I study how they've adapted to these episodes of changing climate over the past millennia.

en: What are some of the main questions in your field?

JG: When we think about understanding how humans can adapt to global warming in the future, we don't generally tend to think about studying the past, but archaeology might be one of the fields that has some of the most important answers for how humans have adapted to changes in climate, not just over the course of a few years, or the course of lifetimes, but over many millennia.

So one of the major questions is what are some of the lessons that we can learn from many millennia of human occupation across these regions? What the archaeological record shows is that the crops that already actually hold the solutions to changing climate, such as millets, already existed and have been cultivated by humans for thousands of years.

en: What are some of the tools you use in your research?

JG: One of the first tools that I use are computational models that predict how changes in climate actually impacted the types of crops that people were able to grow in the past. One of the models that I worked on demonstrated that this climactic cool down that took place around 4,000 years ago had a really major impact on the livelihoods of people on the Tibetan Plateau. Some of the earliest Tibetan people used to grow crops called millets that require lots of heat and that are actually really adapted to the global warming scenario that we live under today, but 4,000 years ago, temperatures got cooler and people were no longer able to grow these crops. They had to replace them with barley. 

Looking back into these episodes of climate that are equal to or maybe sometimes warmer than the changes in climate that we're experiencing today can help provide inspiration for how we should adapt to changes in climate in the future. We’ve funneled billions of dollars into trying to make a few crops like wheat, corn, and soybean heat-resistant and drought-tolerant, but they still require lots of water and they still don't handle high temperatures.

The other tool that I  use is from the archaeological record itself. I'm one of the few foreign researchers to actually have a collaborative archaeological excavation project on the Tibetan Plateau. I work in Jiuzhaigou National Park, one of the most biodiverse areas in China. Chinese authorities decided to resettle the villages of Amdo Tibetans who used to live inside the park. That was because they believed that human impact may be having a detrimental effect on the biodiversity of the area.

Our research has shown that the reality is quite different. We have shown that human occupation in this park goes back for at least the past 5,000 years. The animal bones that we've excavated from the site as well as the seeds that ancient people used to deposit in their trash pits show that they farmed both barley and flax in this area. This is really important. It shows that rather than humans reducing diversity, they actually enhanced plant and animal diversity in  Jiuzhaigou National Park through moderate levels of disturbance, including farming and wood-cutting.

In terms of laboratory research, once I've carried out an archaeological excavation, we extract the ancient seeds and animal bones that people deposited on archaeological sites. We take them back to the lab and identify them. I compare them to modern seeds that I have in the reference collection and identify what people were actually cooking and what they were discarding or even what they were feeding their animals and what might have been burned in these animals’ dung. I do that by looking at these seeds under the microscope and photographing them. And then I create data sets of how their proportions are changing over the millennia of occupation at these sites.

en: At recent international climate talks, one rising issue has been the growing acknowledgement among climate policymakers and scientists of the value of indigenous knowledge. Have you noticed that in your own research?

JG: Absolutely. People who have lived in their home for thousands of years, who have adapted to specific environments, who have co-evolved all of their responses and adaptive behavior to deal with this environment, and lived in this place for a long time really do know something about their home. 

Science has always had the perspective that we can come in and understand a system without really having lived there over the long term, but we're increasingly coming to realize that we don't always have the tools at our disposal and one of our best tools should really be to listen to the voices of indigenous farmers, pastoralists, foragers, and fishers and see how they have managed their environments because they have literally millennia of experience behind them. And that's exactly what we found in Jiuzhaigou National Park.

There were moderate levels of human disturbance, things like raising your animals on pastures, cutting down trees for occasional housing construction or firewood, or the creation of small fields, but it was not the large type of urban disturbance that we are used to seeing. Scientists are finally catching on to the idea that this has really been beneficial to enhancing biodiversity in these landscapes and this has been the case for many thousands of years.

en: What got you interested in this field?

JG: I grew up on a farm in Portugal and I've always been interested in farming. Farming was one of my earliest and happiest memories.  I lived on a small traditionally cultivated farm and we lived a life that was very self-sufficient. I think that's  emotionally where this passion for farming for me really began back in my childhood growing stuff on our small little sustainable farm with my dad.

As I became an archaeologist, I realized that there was so much knowledge in the archaeological record about how people have done this for many, many thousands of years and this is something that we could stand to learn from.

Industrial farming actually contributes to carbon emissions in a very impactful way and people don't think about this. Part of the issue is that when people over-fertilize either rice paddies, or they over-fertilize fields with nitrogenous fertilizers, this releases nitrous oxide, another greenhouse gas that is roughly 300 times more potent than CO₂ and also depletes stratospheric ozone. That is one of the reasons why industrial farming actually does have a very high carbon footprint and why it is contributing to global warming and why it is urgent for us to think about other types of solutions and farming.

en: Why did you want to come to Scripps Oceanography?

JG: As you can see, a lot of my work is really interdisciplinary. On one hand, I work with a lot of climate data and create models of how past climate change impacted humans’ ability to grow crops, but on the other hand, I'm also an ethnobotanist and I study how humans have used plants in the past. I'm also an archaeologist, I carry out excavations, so for me, part of the lure of Scripps was it was exciting to join an institution where people are really engaging in this type of cross-disciplinary research and research that doesn't easily find itself in one field.