Get the Gizmo ready:
Modeling the carbon cycle
Select the MODEL tab.
Introduction: Humans have been burning fossil fuels rapidly for the past 250 years. As a result, the amount of
atmospheric CO2 has increased by about 40% since the year 1800. By measuring how much carbon moves into and out of
the atmosphere, scientists can predict the change in the amount of atmospheric carbon dioxide every year.
Question: How can we model changes in atmospheric carbon over time?
1. Observe: The MODEL tab shows a simplified model of the carbon cycle. The ovals represent carbon reservoirs,
where carbon is stored. The unit “GtC” stands for gigatonnes of carbon, where one GtC is equal to one trillion
kilograms of carbon. The arrows represent how much carbon moves from one reservoir to another each year, in
gigatonnes per year.
A. Look at the arrows pointing toward atmospheric CO2. What are the two major sources of atmospheric carbon?
Fossil Fuels and soil.
B. A carbon sink is a location that stores carbon for a long period of time. Which two carbon sinks remove carbon
from the atmosphere?
Plants and oceans
C. Without changing the Gizmo, list the carbon reservoirs from largest to smallest.
Oceanic CO2, Sediments, Fossil Fuels, Soil, Atmospheric CO2, and Land Plants
Note: The largest carbon reservoir is actually Earth’s lithosphere, which contains about 80,000 GtC. However, there is not
much exchange between the lithosphere and the other reservoirs on short time scales.
2. Experiment: If necessary, click Return to original settings. These settings approximate present-day conditions, but
should not be taken as exact values.
A. What is the total amount of carbon removed from the atmosphere each year by the ocean and land plants?
The total amount of carbon removed from the atmosphere was 65 GtC
B. What is the total amount of carbon added to the atmosphere from soil and the burning of fossil fuels?
The total amount of carbon added to the atmosphere was 69 GtC
C. How much will atmospheric carbon change in one year?
The total amount of carbon added to the atmosphere was 69 GtC and the amount of carbon that was
removed from the atmosphere was 65 GtC
The total amount of carbon added to the atmosphere
This study source was downloaded by 100000843746907 from CourseHero.com on 04-09-2022 19:12:41 GMT -05:00
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