A new documentary provides insight into how ancient climate affected human evolution. The video, available on YouTube, focuses on the research conducted by the University of Arizona-led Hominin Sites and Paleolakes Drilling Project, an international collaboration of geologists, anthropologists and climate scientists.
UA Distinguished Professor of Geosciences Andrew Cohen and his colleagues have been studying the connections between climate and human evolution in Africa’s Rift Valley for more than a decade.
“Of the more than 10 species of hominins that have existed on Earth, all have gone extinct except ourselves,” said Cohen, director of the project. “Some of these extinctions may have been due to climate change, and this may have important implications for the future of our own species.”
More than 100 scientists from 11 countries are part of this unprecedented project to understand the environmental context of human origins, he said.
“A Human Climate,” the documentary made in 3-D by Earth Images Foundation, tracks the scientists as they investigate the climate that prevailed when key hominin fossils such as Lucy and Turkana Boy were alive. Hominins are the group of organisms that includes humans and our fossil near-relatives and ancestors.
The researchers extracted sediment from dry lake beds near important ancient hominin fossil and archaeological sites in Kenya and Ethiopia.
Lake beds can supply a record of the past environment, because a variety of environmental materials, including pollen and animal remains, are deposited on the bottom of lakes year after year.
To obtain ancient sediment from the depths of dry lake beds, the scientists used a drill rig that collected continuous sediment cores in 10-foot segments, from as deep as 940 feet below the Earth’s surface. Some of the cores contain lake sediments as much as 3.5 million years old.
The scientists are using data from the sediment cores to reconstruct climate and ecological changes in eastern Africa.
The documentary, which features interviews with many of the researchers, shows the researchers drilling for sediment in Kenya and Ethiopia and also collecting hominin fossils near the drill sites.
By analyzing fossil pollen, charcoal and lake organisms in the cores, the team is reconstructing the ecosystems that early humans lived in and depended upon. UA geosciences faculty member Owen Davis and several UA graduate and undergraduate students are some of the researchers analyzing the cores.
“We’re just starting to analyze the drill cores,” Cohen said. “We expect the drill cores are going to provide us with a lot of new information about African climate over the last 3.5 million years of human evolution.”
In addition to the field team, the project includes researchers who can model the region’s paleoclimate and environment. The international modeling team, led by Joellen Russell, a UA associate professor of geosciences, also includes UA geosciences faculty members Jon Pelletier and Jianjun Yin.
The computer models will reveal the atmospheric and landscape processes underlying past environmental change in Africa and how the resources early humans relied on would have responded to those climate changes.
The researchers anticipate their findings will transform our understanding of how environmental and climate change affected the evolution of our ancestors and also have implications for humans today.
Source: University of Arizona