Self-study
P1
Experts anticipate that global atmospheric concentrations of carbon dioxide (CO2) will have doubled by the end of the twenty-first century. ██ ██ █████ ████ ███ ███ ██████████ ██ ██████ ███████ ██ ████████ █████ ██████ ████ ██ █████ ██████████ ██ ████ ████ ███ ███████ ████████ ███
Intro topic ·
Global CO2 will probably increase
CO2 contributes to global warming.
Perspective from some research ·
Increased CO2 can lead to agricultural abundance, which can decrease rate of global warming
If there are more plants, those plants might draw more CO2 from the atmosphere, which might slow down global warming.
P2
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Critique 1 ·
More CO2 could lead to less agricultural yields
Although CO2 increases plant growth rate, it affects some plants more than others. Weeds might grow faster and outcompete certain good plants.
Consequence of Critique 1 ·
Different growth rates in plants can damage ecosystems
Weeds burn easily. More weeds could lead to more fires.
P3
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Critique 2 ·
More CO2 unlikely to slow down rate of global warming
Support for Critique 2 ·
Global warming leads to more decomposing peat, which will release more CO2 into atmosphere
Although more CO2 can lead to more plant growth, which can absorb more CO2, that's counteracted by increased release of CO2 from peat.
Passage Style
Critique or debate
22.
According to the passage, Billings' ████████ █████████ █████ ███ ██ ███ █████████ ██████████
a
Which kind of ███████ ████ ██████████ ███ ████████ ███████████ ████████ ██ ██ ██████████ ████ ██ ████
The author says that Billings’ research on the tundra is important because high-latitude habitats like the tundra are expected to experience the greatest temperature increase. But Billings’ research never addresses which habitat will experience the greatest temperature increase.
b
How much will ██████ ████████████ ████ ██ ██████ ██ ███ ██████ ██ ███ ███ ██ ███ ████████████ ████████
This is not stated in the passage. Billings’ never tells us how much summer temperatures will rise. He just says that if they rise by four degrees Celsius, then the tundra will release 50% more CO2.
c
Will enhanced plant ██████ ███████████ ████████ ███ ████ ██ ██████ ███████ ████ ███ ████ █████████ ██ ████████
In Billings’ global warming simulation described in P3, plant growth did increase. But, because of increased peat decomposition, CO2 levels also increased. This suggests that enhanced plant growth will not necessarily decrease the predicted rate of global warming.
d
Would plant growth ██ ██████████████ ████████ ██ ███████████ ██████████████ ██ ███ ████ ██ ██████ ██ ███ ███ ██ ███ ████████████ ████████
This is not answered by Billings’ research. In P1, we see that experts believe CO2 levels will double by the end of the century. In P2, we see that some studies show that increased CO2 will differentially increase plant growth rate. But Billings’ research doesn’t address these points.
e
Does peat decompose ████ ███████ ██ ███ ██████ ██████████ ████ ██ ████ ██ █████ █████ ██ ████████ ████ ███████████ ██████████████ ██ ███ █████████
This is not stated in the passage. Billings never compares the rate of peat decomposition in wet tundra grasslands to peat decomposition anywhere else.