Self-study
In recent years the climate has been generally cool in northern Asia. ███ ██████ ███████ ████ ███ ███████ █████ ███████████ ███ ████████ ██ ████████ ████ ████ ████████ ██████ ████ █████ ██████ ██████ ███ ██████ ██ ████ █████ █████ █████ █████████ ██████████████ ██ ███ ████ ████████ ███ █████████ ███████ █████ ███████████ ███ ████████ ████████ ██████ █████ ███████ ███ ████████ ██ ██████ ███ █████ ███ ██████████ ███████ ████ ███ ██████ ██████ ██ ████ ██ ███ ████████ █████ ████ ████████ ██████ ███ ████ ████████
"Surprising" Phenomenon
Why do scientists expect crop yields to decrease when the crops seem to thrive in a warmer and wetter climate?
Objective
Any hypothesis that resolves this paradox must explain why crop yields are expected to decrease over the coming century. It may be a consequence of a climate that is consistently warmer and more humid, or it may be unrelated to climate.
18.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████ ███████ ██ ███ ███████████ ██████
a
Crop yields in ████████ ████ ███ ████████ ██ ██████ ████████ ████ █████ ███ ███████ █████ ███████████ ███ ████████ █████ ████████ ████ ██████ ███████
This is information about southern Asia, not northern Asia. Rather than resolve the paradox, this states that the paradox does not exist in a different region.
b
Any increases in ███████████ ███ ████████ █████ ██ ███████████ ██ ██████ ██████ ██ ███████████ ██████ ████████ █████ ██ █████ ██ █████ ████████████
This deepens the paradox by implying a warmer, more humid climate should result in greater crop yields. If plants rely on carbon dioxide to grow, and the impending changes will result in more carbon dioxide in the atmosphere, then crops should benefit.
c
The climate in ████████ ████ ███ █████████ ████ ███ ████ ███ ███ ██ ██████ █████ ███ ███████████ ██ ████ ████ ██████ █████ ██ ██████ ████████████
This is a reason to expect crop yields will decrease. A consistently warm and humid climate will benefit pests, which over the long term may cause damage to crops that outweighs the potential benefits of a changing climate.
d
In many parts ██ █████ ███ █████████ ██████ █████████████ ████ █████ ██████ ████ ██████ ███ ██████ ████████ █████ █████ ████ ██████ █████ ███████ ██ █████████
This deepens the paradox by further implying the changes in climate should cause crop yields to increase, not decrease. If a warmer, more humid climate causes edible plants to flourish, crops should not be expected to suffer.
e
The recent climate ██ ████████ ████ ████████ ████ █████ ████ █████ ██████ █████ ██████ ███ ███████
This does not explain why crop yields are expected to decrease over the next century. If changes in climate happen to allow more winter farming, that would be expected to increase yields, not diminish them.