A simple calorimetric experiment that highlights aspects of global heat retention and global warming

There are two lines of direct evidence that increasing Atmospheric greenhouse gas concentrations are presently contributing to increased global heat retention: (i) increasing surface, ocean, and atmospheric temperatures, and (ii) observed long-term melting of surface ice. Experimental evidence from satellites, aircraft, and ground-based sensors indicates that both lines of evidence support the hypothesis of increased heat retention (5-9). While recent increases in the observed global average surface temperature have been small - approximately 0.17 °C per decade (9) - worldwide observations of melting ice have been more conspicuous (5-7, 10). At the present time, the directly observed melting of surface ice indicates more strongly than the observed temperature increases that the earth has entered into an era of increasing greenhouse effects. Students who have completed the laboratory exercise described here have emerged with a stronger understanding of these key issues and are able to connect them to the simple calorimetric principles that are typically covered in most first-year chemistry courses.