Report: Strategic research program needed to determine whether, how past climate influenced human evolution

Understanding how past climate may have influenced human evolution could be dramatically enhanced by an international cross-disciplinary research program to improve the sparse human fossil and incomplete climate records and examine the link between the two, says a new report from the National Research Council.

Climate and fossil records suggest that some events in human evolution -- such as the evolution of new species or movements out of Africa -- coincided with substantial changes in African and Eurasian climate. This raises the intriguing possibility that environmental factors affected or controlled our species' evolution. By altering the landscape, past changes in climate may have exerted pressures that led to genetic selection and innovation in humans. But because the human fossil record and our understanding of past climate conditions are incomplete, the details of how climates influenced human evolution remain unclear.

The report recommends several research initiatives over the next 10 to 20 years:

• a major effort to locate new fossil sites using modern remote-sensing tools and traditional ground examination. In addition, many existing sites should be further analyzed to better determine when species first appeared and then disappeared, along with noting specific adaptations and behaviors. Currently, efforts to understand links between climate and evolution are limited by gaps in the human fossil record.
  
• a comprehensive program to drill on land and in lakes and ocean basins in the regions where humans evolved. An integrated drilling program should be part of a larger effort to collect more data to reconstruct past environments -- including temperatures, precipitation, and vegetation -- near human fossil sites. Describing the plants and animals that lived with our human ancestors is a key component for understanding past environments.
  
• a major investment in climate modeling experiments for the key time intervals and regions that are critical for understanding human evolution. The objective would be to characterize regional and local climates in the areas where humans evolved and to integrate these modeling experiments with records of the past ecology and environment.
  
• an enhanced public outreach effort, including teaching curricula and traveling exhibitions, that takes advantage of broad public interest in human evolution and climate change.