After the record-breaking heat waves of summer 2012 and other weather disasters this fall, the threat of climate change continues to confront us.

What will be the consequences of more warming of our atmosphere and oceans, and how should society prepare for them? What can we learn from the history of past weather extremes and climate changes? In particular, how did human societies respond to past climate changes that included droughts, hurricanes, forest fires and crop failures?

Answering such questions requires close collaboration among scientists versed in the disciplines of archaeology, climatology, geology, ecology and dendrochronology (tree-ring sciences). Fortunately, the University of Arizona has leading researchers and departments in all of these fields, including the Laboratory of Tree-Ring Research, which has been a melting pot for such collaborative studies since the 1920s.

Now a multidisciplinary group of UA scientists is combining their unique skills and research tools to understand changes - past and recent - in the greater Mediterranean region. The new Center for Mediterranean Archaeology and the Environment (CMATE) - a partnership of the UA School of Anthropology, the UA School of Earth and Environmental Sciences (which includes the Laboratory of Tree-Ring Research), Cornell University and the Malcolm Hewitt Wiener Foundation - will study climatic, geological and human history in the lands bordering the Mediterranean Sea.

These studies will follow in the footsteps of UA astronomer Andrew E. Douglass, founder of the Laboratory of Tree-Ring Research and inventor of dendrochronology, and Emil Haury, a renowned UA archaeologist. They investigated the history of the great Southwestern cliff dwellings and ancient pueblo ruins.

Using dendrochronology, Douglass and Haury discovered that a "Great Drouth" occurred during the 1280s. This drought corresponded with a sudden and massive migration of Native Americans from the Colorado Plateau to the Rio Grande in New Mexico, where their descendants, the Puebloan people, live today.

We have learned since Douglass' and Haury's day that a complex set of factors, including the late 1200s drought, were likely responsible for this mass migration. A common historical pattern emerges from these and similar studies: climate change sometimes triggers societal upheaval, especially when ecological and social factors combine to make human systems particularly vulnerable.

Like our intellectual forefathers Douglass and Haury, CMATE will investigate how human and environmental factors have affected the course of human history.

Droughts and other natural disasters such as volcanoes, earthquakes and tsunamis played havoc on past Mediterranean societies, sometimes leading to wars and the collapse of great empires. The written records of the Egyptians, Greeks and Romans tell us, for example, that societies were alternately blessed and cursed by favorable and unfavorable climates.

CMATE brings the world's leading experts in dendrochronology, radiocarbon dating, geosciences and archaeology together to answer the question: What can we learn from both cultural and natural histories of the Mediterranean region that will provide useful insights on how societies are sustained over time or how they collapse?

Stay tuned: We expect to learn much in coming years and to share our findings with all.

About the scientist

Thomas W. Swetnam is a University of Arizona Regents' Professor and director of the world's premier center of tree-ring research and education, the UA Laboratory of Tree-Ring Research. He studies changes in climate and forest disturbances using dendrochronology (tree-ring analyses). An expert on wildfire history and ecology in pine and giant sequoia forests of the Western United States, Mexico and South America, Swetnam is studying the links between forest fires, climate and human history in the Southwestern United States and central Siberia.

Experience Science

• Center for Mediterranean Archaeology and the Environment:

• Laboratory of Tree-Ring Research:

• School of Anthropology:

• School of Earth and Environmental Sciences: