1) (10 points) As discussed in class, it has been estimated that the total water mass added to the terrestrial oceans over Earth's history of 4.5 Ga should lie between 4 and 22%. How does this compare to the amount of water added to the hydrologic cycle from degassing of the Earth (~ 1 km3/y) and the amount of water used in NYC (~1.1 billion gallons per day)? Express the results in the same units and express their relative magnitude in a comprehensible way.
2) (6 points) As mentioned in class, in the US about 500 km3year-1 are withdrawn for off stream use. Express the NYC water consumption (1.1 billion gal day-1) as a fraction (%) of this.
3) (8 points) Imagine you would spread the oceans evenly over the whole Earth, how thick a layer of water would you obtain? Perform the same calculation for atmospheric waters (terrestrial plus marine) and for ice & snow. The diameter of the Earth is: 7,926 miles. Surface of a sphere = 4·3.14·r2. Express your result in meters. For the volumes of the individual reservoirs, use the numbers on the figure below. Assume that the density of water is 1 gcm-3.