A Class Project for Investigating Possible Future Local Effects of Global Climate Change through Student Analysis of Fossil Faunas

Abstract

A common question posed to environmental scientists by nonscientists, particularly policymakers, is the following: In a world that is globally warmer, what will the new climate be like in specific geographical regions? This question has been and continues to be addressed by computer modeling, a technique that is out of reach for vast majority of students. However, an alternate approach to investigating this issue exists that is more practical for students. Past climates can be inferred for specific regions from fossils, utilizing climate tolerances of related modern organisms. When these inferred past climates correspond to periods of the Earth’s history where levels of carbon dioxide were as high or higher than today, these data can be used to extrapolate possible future local climates in a globally warmer world. The last Pleistocene interglacial period (known as the Eemian), which occurred approximately 120,000 years ago, is an ideal time period for studies of this kind for the following reasons. First, carbon dioxide levels were elevated at this time to levels approximating modern global conditions, and the world was warmer as evidenced by a much higher sea level than exists today. Secondly, most Eemian-age animals (especially mollusks) still exist, have known climate tolerances, and are relatively common as fossils. Students examining fossil mollusk faunas have applied this methodology to infer the Eemian climates of South Florida and coastal Virginia and found unexpectedly that for both regions the Eemian climate did not greatly differ from the modern one. The methodology described here can be used to address other important questions and puts such authentic and potentially valuable scientific research within practical reach of student scientists.