I hope you will find the following guide easily adjusted for education level and class size.
1) Understand basic elements of global shading (AKA: dimming) beyond particulates, such as timing and altitude. Examples: The same clear desert sky that provides for scorching days also allows freezing nights, as accumulated heat races unimpeded toward space (hot day, cold night). In contrast, a sky overcast with clouds will shade the sun’s light and also provide an insulating effect at night, slowing heat loss (cold day, warm night).
2) Appreciate irrefutable weather dynamics and human made causation. Explore: Ethiopia’s deforestation effects of just the last century and compare with America's dust bowl. Research the effect of historical “tree taxes” in the Middle East. Study the alarming rise of tempertures in Europe, where reduced CO2 emmissions have also cleared the sky of shading particulates.
3) Distinguish the major components of our air pollution and how changes in both their quantities and ratios to each other can have surprising effects. Example: An increase of mostly clear CO2 and/or methane increases Earth’s insulation. This is especially problematic when high airborne particulates are simultaneously reduced, because their shading effect (dimming or cooling offset) is lost, while the extra insulation continues to retain heat for decades.
Sample lesson guide:
___ Gather (recycle) a discarded black plastic bag, two pieces of 8 X 11 paper, a large piece of aluminum foil, and some pieces of clear plastic bubble wrap or similar swimming pool cover. Boldly label one 8 X 11 sheet as HIGH ALTITUDE and the other as LOW ALTITUDE. Take the class outside on a sunny day and have three volunteers stand side by side to help demonstrate as follows.
___ The first student places the LOW ALTITUDE sign at ankle height to simulate elevations from the Earth’s surface up to small aircraft traffic patterns (hold down with feet if windy). This same student holds the HIGH ALTITUDE sign high overhead, to indicate elevations for commercial jet operations and above.
___ A second student initially holds the piece of black plastic overhead to simulate an enlarged black carbon particulate (soot) at a very high altitude. Have the third student confirm that the shadow from the high soot is cooler than the ambient temperature. Discuss how this very high altitude allows heat to dissipate from the particulates more directly into space, while providing a dimming (cooling) effect below.
___ The second student now slowly lowers the “soot” as if floating to the ground. Have some other classmates hold their hands above this black plastic to confirm the heat output is now increased down on our level. Discusshow altitude matters when considering the temperature effects of black carbon and other particulates.
___ Have the third student repeat this experiment with the aluminum foil instead, with the second student confirming that the reflective foil is cooler to the touch, while its shadow cools the same as the black plastic bag shadow.
___ On the way back into the classroom, scoop a small amount of clean sand or soil onto the foil or bag to evaluate CO2/methane effects on our atmosphere. Place one layer of the clear bubble wrap on a table to simulate our atmosphere’s previous insulation factor (can be compared to “R values” in roofs).
___ Sprinkle some sand or soil on top of this first layer of insulation and discuss how volcano eruptions can shade large areas, cause global dimming, change weather patterns, and threaten the food supply. Clean off the first layer to restore the era’s average atmospheric balance.
___ Sprinkle more “particulates” on a second piece of bubble wrap and lower it onto the first. Announce that this represents the combination of CO2 and soot that has been continually added since the industrial revolution, faster than absorbed below. While not a perfect balance of insulation to shading, these two major components have somewhat offset each other’s individual effects. (Note that adverse weather conditions can still occur.)
___ Now announce the removal of much of the toxic air pollution and clear off most of the “particulates” from the top layer, but leave both pieces in place. Remind the class that the second heat retaining layer of bubble wrap represents extra CO2 which will remain aloft for many decades (unless otherwise consumed).
What is the possible outcome of a lingering excess CO2 insulation effect, while the shading effect of higher altitude black carbon is quickly reduced by cleaner energy?