The answer is : temperature estimated using any of several methods. The most important variable in reconstructing ancient climate is temperature estimated using any of several methods.
The most important variable in reconstructing ancient climate is the temperature that is estimated using methods like temperature proxy and oxygen isotope indicator method.
Explanation:
Any climate is primarily governed by the temperature. It stands as the most important factor on which the existence of the other factors is dependent.
In order to reconstruct the ancient climate, it is necessary that the temperature that caused the ancient climate to be how it was is determined first.
