Just as the increase in atmospheric CO2 is causing the global air temperture to rise, the container with the added CO2 will trap more heat inside and will show a higher internal temperature.
Overview
This activity/demonstration can be used directly following lessons on greenhouse gasses and their effects on warming the atmosphere by allowing shortwave UV energy
In this one hour presentation, PolarTREC teacher John Wood explains the scientific work in the Carbon Balance in Warming and Drying Tundra expedition from Healy, Alaska.