The simulation exercise uses a STELLA-based model called Daisyworld to explore concepts associated with Earth's energy balance and climate change. Students examine the evolution of a simplified model of an imaginary planet with only two species of life on its surface -- white and black daisies -- with different albedos. The daisies can alter the temperature of the surface where they are growing. While the atmospheric water vapor and CO2 are assumed to remain constant (i.e., the main greenhouse gases of the planet do not change), the solar energy input changes over time. Students explore the outputs from the basic model and then make changes to look at the effect of changing albedos, changing growth factor curves and plagues (i.e., periodic changes in death rates) .
