- Volcanic Eruptions, Earthquakes, and Drought:Environmental Challenges for the Ancient Maya People of the Antigua Valley, Guatemala
Presidential Address delivered to the Association of Pacific Coast Geographers, 73rd annual meeting, Coeur d'Alene, Idaho, September 17, 2010
Before the APCG meeting last September, I was on Cape Cod with my sister, enjoying the last of the summer. With the development of Hurricane Earl, I became concerned that we would not be able to fly out on Friday morning, when the hurricane was projected to hit the Cape. It had been nearly twenty years since the last hurricane hit Massachusetts, and that last one pulled up and tossed the locust trees like jackstraws all over our property, fortunately not hitting the house. The change in the landscape was dramatic after that storm, but today only a few bare snags are left among the full young trees as evidence of the past event. However, the ocean beaches have been migrating landward, eroding rapidly back with every big storm. This process is being exacerbated by sea-level rise. It's predicted that within the next few decades, Provincetown, on the north end of the Cape, will be cut off from the lower section, making it an island. Eventually this Pleistocene moraine will disappear under the waves. By the end of this century, a hurricane as far north as Cape Cod—and even Newfoundland—may not be such an unusual event, as the increasingly warm Gulf Stream carries its heat up past the Cape. The Eastern U.S. experienced record-breaking heat last summer as well. [End Page 15]
As you heard in the Climate Change Plenary at Coeur d'Alene, global climate is rapidly changing the world around us. Catastrophic droughts and floods, as occurred last summer in Russia, Pakistan, and China, may be considered aberrations of weather, or they may be indicators of climate change. Either way, these events have tremendous impacts on millions of people, with food production such as wheat and rice crops affected around the world, and freshwater supplies scarce to the millions at the sites of devastation. Both of these types of events can be traced to variations in atmospheric circulation and ocean temperatures, in response to warming air temperatures. In many parts of the world, vegetation and animals are being impacted, in some cases migrating to cooler environments, in some cases becoming threatened with extinction.
Vegetation is an excellent indicator of climate because it responds relatively quickly and directly to variations in mean temperature and precipitation. Geomorphic systems, such as erosional and depositional episodes caused by floods, storms, or drought, also leave evidence on the land. Traces of geomorphic and vegetation change are very helpful to researchers who are interested in learning about the landscape history—the paleoenvironment—of different parts of the world. We are interested in knowing what has happened in the past in order to understand the drivers and responses of natural systems. These also help project what might happen in the future, given certain changes in the systems. It is essential these days to be able to differentiate between natural climate cycles and human-induced changes. Therefore it is really useful to study evidence of past environments in association with human occupations. Moreover, understanding the environmental context in which humans have developed technologies, such as domestication of food crops and agricultural techniques, resulting in food security that allowed for settlements, and ultimately civilizations, also helps us to understand not only how humans responded to natural variations, but also how they changed their environments. The study of past environmental contexts of human occupations, which we call geoarchaeology, is a certain passion of mine.
For more than ten years I have been collaborating with a team of physical geographers and archaeologists who have been working out the environmental and cultural changes that occurred during the period when the pre-Maya people were living in Guatemala. My main focus has been on the highland valley of Antigua, but I also worked on sites along the Pacific Coastal lowlands and spent some time at a Classic Maya site in the northern [End Page 16] Yucatan. As...