To identify the assumption on which the argument relies, let's break down the argument:
Premise: Increased global temperatures lead to enhanced water evaporation and more stored moisture in the atmosphere, causing heavy rains following droughts.
Premise: Similar weather patterns occurred during the Pliocene Epoch, a time of higher global temperatures.
Conclusion: The current pattern of prolonged droughts followed by intense rainfalls is a clear indicator of climate change due to increased global temperatures.
The argument claims that because similar weather patterns were observed during a past period of higher global temperatures (the Pliocene Epoch), our current weather patterns are due to climate change (increased global temperatures).
To strengthen this argument, it assumes that the cause of the weather patterns during the Pliocene Epoch is the same as the cause of current weather patterns. Without this assumption, the comparison to the Pliocene Epoch would not support the conclusion that current weather patterns are due to climate change.Evaluation of Answer Choices:
(A) The conditions that caused similar weather patterns during the Pliocene Epoch must be the same as those causing current weather patterns.
This assumption directly links the past and present causes of weather patterns, making the argument valid. If the conditions are different, the comparison to the Pliocene Epoch would not support the conclusion.(B) Other factors besides global temperatures, such as ocean currents or volcanic activity, did not significantly influence weather patterns during the Pliocene Epoch.
While this might be relevant, it is not the primary assumption. The argument primarily relies on the similarity of causes, not on ruling out other factors.
(C) Without evidence of increased global temperatures, the claim that current weather patterns are due to climate change would not be credible.
This is a general statement about the evidence needed for the claim but does not address the specific comparison to the Pliocene Epoch.
(D) If global temperatures continue to rise, the frequency and severity of these weather patterns will certainly increase.
This is a prediction about the future, not an assumption underlying the argument about the past and present relationship.
(E) The mechanisms that caused climate change in the past are fundamentally different from those causing current climate change.
This contradicts the argument rather than supporting it, as it suggests a difference rather than a similarity.
Therefore, the assumption that the argument relies on is:
A