If the Atmosphere's "Optical Thickness $n$ Depended on the Ratio of the Concentrations to the First

Multiple Choice

If the atmosphere's "optical thickness" $n$ depended on the ratio of the concentrations to the first power instead of to the $1 / 2$ power in equation T10.8a, would this accelerate or brake the warming compared to the model in the text?
Equation T10.8a:}
$$n=n_{b}\left(\frac{400 p p m}{280 p p m}\right) ^{1 / 2}=0.605\left(\frac{400}{280}\right) ^{1 / 2}=0.723$$

A) Accelerate}
B) Brake
C) No change