Dimming the Sun Nova Video Guide

Dimming the Sun by Nova
1. What was the significance of the 9/11 2001 event in assessing
the effect of global dimming?
2a. What effect did grounding of the planes after 9/11 have on daily temperature
ranges? 2b. Why was temperature affected?
3. What did Gerald Stanhill’s studies – twenty years apart – indicate?
4. One would think that decreases in solar radiation would cool the Earth. But yet the
Earth is warming. Why?
5a. What is the pan evaporation rate?
5b. Has it been going up or down in the last few decades?
5c. Why?
6. Two independent data sets - pan evaporative rates and solar radiation rates – now
lead to the same conclusion, i.e., that global dimming is real. Is this phenomenon
worldwide, regional, or local?
7. What is causing the decrease in solar radiation?
8a. Greenhouse gasses responsible for global warming (CO2 and water vapor) are
invisible. How does this compare with substances that cause global dimming?
8b. What kind of particulates have increased in clouds?
9. What effect does the presence of many small water droplets in clouds have, as
opposed to fewer larger drops?
10. How do clouds that are more reflective affect rainfall? Give the example from Sahel
in Africa.
11. The conclusion thus far is that we must reduce air pollution to improve human health
(respiratory diseases), global dimming and its associated droughts, famines, etc. But
what would happen if we greatly reduce air pollution? (Quite the irony here!)