Predicting Biological Response to Global Warming: A Laboratory Activity to Promote Discussion

Abstract

A measured rise in the carbon dioxide content of the atmosphere is expected to have a significant impact on the Earth's climate and biota. Within the next 50 years the average global temperature is predicted to rise from 0.80F to 2.50F (1.5?C to 4.5?C) (Jager 1988; Houghton et al. 1990 as cited by Ojima et al. 1991) due to a phenomenon called the greenhouse effect. That is, while CO2 and other atmospheric gases readily permit shorter, solar wavelengths to penetrate to the Earth, they trap longer, re-radiated wavelengths from the Earth, causing atmospheric temperature to rise. Presently, teams of scientists are working on complicated computer models to predict changes in global temperature and precipitation (Bolin et al. 1986; Ojima et al. 1991). Articles discussing the impacts of changes in temperature and precipitation on global and regional scales are frequent in the popular press (Nash 1987; Pain 1988; Revkin 1988; Adler & Hager 1988). The exercise described below enlists students and teachers as local experts to predict the effect warmer temperatures will have on agroand natural ecosystems with which they are familiar. In pursuing the activities the students will gain an understanding of the greenhouse effect, an appreciation of how climatic change might impact at least one agricultural system and one natural ecosystem, and an ability to identify factors that determine which organisms occur together naturally. These activities can be adapted to different instructional levels and to different geographical regions. For those who live within an