I’m studying and need help with a Environmental Science question to help me learn.

• Required: Snowball Earth, Paul Hoffman and Daniel Schrag, Scientific American, Jan. 2000.
• Optional: A Neoproterozoic Snowball Earth. Hoffman, P., Kaufman, A., Halverson, G. and Schrag, D. Science. August 1998.
• Optional: The BBC Horizon Documentary Snowball Earth: How the Planet Froze and Lived to Tell is available on YouTube

Assignment:

1. The roots of the snowball earth hypothesis go back almost 100 years.What were the earliest clues that the earth may have been completelycovered in ice at some time in the past? (15 points)
2. Carbon dioxide (CO2) is often called a greenhouse gas . What effectwould decreased CO2 levels in the atmosphere have on the climate?Explain (15 points)
3. A portion of all solar radiation (heat from the sun) is absorbed bythe earth and a portion is reflected back out into space. The amount ofsolar radiation that a material reflects back out to space is called thealbedo . Do sea-ice and continental glaciers have a higher or loweralbedo compared to sea-water and land vegetation? What effect wouldexpanding glaciers have on the amount of solar radiation that isabsorbed by the earth? Explain. (15 points)
4. According to the Snowball Earth hypothesis, what caused the earth tobecome completely frozen over (global glaciation)? Specifically,describe the plate-tectonic conditions, and the chemical and physicalmechanisms that drove the earth into a deep-freeze. (15 points)
5. Previous to the work of Hoffman and Schrag, many scientists thoughtthat the earth would not recover (warm) from a snowball earth, if itever happened. Describe Hoffman and Schrag s hypothesis of how the earthwould have reversed the deep freeze and entered a global hothousestate. (15 points)
6. Paleontologists have observed that the period directly following theneo-proterozoic is characterized by a huge expansion and diversificationof life. This significant evolutionary interval is oft referred to asthe Cambrian Explosion . According to the authors how did the snowballearth significantly effect, and perhaps even catalyze, the CambrianExplosion? (15 points)
7. What do you think about the Snowball Earth Hypothesis? Is it areasonable hypothesis in light of the evidence uncovered so far? Whatcould be an alternative hypothesis to explain the existence of so manyglacial deposits found directly underneath (and immediately before intime) tropical warm ocean deposits? (10 points)