Name ______Date______Per. _____
Global Warming Problem Set
Weighing the Atmosphere:
At sea level, the weight of a 1 cm2 column of atmospheric air is approximately 1 kg. This value, 1kg/cm2, is also known as the atmospheric pressure. For this analysis, we will assume a featureless Earth without continents. This will simplify, but not significantly alter, your calculations.
1. How much does the atmosphere weigh over each square meter of Earth’s surface? Express this in tonnes (units of 1000 kg). Conversion factors: 104 cm2 = 1 m2 (note that the linear conversion is squared for the area conversion value); 1 tonne = 1000 kg.
2. How much does the atmosphere weigh over each square kilometer?
Conversion factor: 106 m2 = 1 km2
3. The area of the Earth’s surface is approximately 516 x 106 km2. What is the weight of the entire atmosphere in tonnes?
4. While your answer to #3 is a very large number, the mass of the entire Earth is 6 x 1024 kg or 6 x 1021 tonnes. How many times larger is the mass of the Earth compared to the mass of the atmosphere?
5. CO2 comprises 0.05% by weight of the atmosphere. What is the weight of CO2 in tonnes in the atmosphere?
6. There is an increase of approximately 7.7 billion tonnes of CO2 per year due to burning of fossil fuels and deforestation. What percentage of the total amount of CO2 in the atmosphere (your answer to question 5) is this annual increase in CO2.?
7. The actually amount of anthropogenic CO2 emissions from burning fossil fuels (as well as decreased consumption of CO2 due to deforestation) is greater than the 7.7 billion tonnes per year cited in question #6. This difference is due to the fact that some of the CO2 is removed from the atmosphere by carbon sinks (also known as reservoirs). Identify and explain two major carbon sinks.
8. Sea level rise from global warming will be from more than just the melting of polar ice caps. The coefficient of thermal expansion for seawater is approximately 0.00019 per degree Celsius. This ratio does not have any unit for the numerator because it allows the calculation of the thermal expansion for any height unit used. For example if a 1 mile depth of water was heated, it would expand by 0.00019 miles for every degree Celsius of temperature increase.
To calculate how much a temperature increase would increase sea level, multiply the average ocean depth (in cm) by the coefficient of thermal expansion by the number of degrees of seawater temperature rise.
How many centimeters would each 1oC increase in seawater temperature cause sea level to rise? The average ocean depth is 3,800 m (380,000 cm).
(This calculation will be an approximation since the depth of the ocean varies and the heating is not distributed evenly.)