Statement I: Evapotranspiration helps in classifying the climatic types. Statement II: Only temperature affects evapo-transpiration, hence it can be used for classifying the climatic types.

Statement I is true as evapotranspiration is a fundamental metric in climate classification. For instance, C.W. Thornthwaite used Potential Evapotranspiration (PET) as a primary index to define climatic boundaries and moisture regimes. However, Statement II is false because evapotranspiration is not affected by temperature alone. Scientific evidence confirms that it is influenced by a complex interplay of multiple factors, including solar radiation intensity, relative humidity, wind speed, and soil moisture availability [3]. While temperature is a significant driver, wind replaces saturated air layers with unsaturated ones to increase evaporation, and low humidity provides more space for moisture [3]. Therefore, using temperature as the sole determinant is scientifically inaccurate, even if some simplified empirical models rely heavily on it. Consequently, Statement I is a valid geographical principle, but Statement II is factually incorrect.

Sources

1. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Factors Affecting Rate of Evaporation > p. 328