Non-Linear Solubility Trend I am doing a lab on carbon dioxide solubility in water and I have a non-linear trend which seems to agree with the accepted trend. I am examining the change in solubility as a function of temperature. In the experiment I titrated carbonated water with sodium hydroxide and used molar ratios to determine the carbon dioxide content. The following graph shows the accepted trend:



(Graph from: http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html)

I've been thinking but, can't seem to figure out why the trend is non-linear. Is there any intuition behind this trend?
The solubility can be thought of as an equilibrium. The Van 't Hoff Equation describes the relationship between any equilibrium constant and temperature. 

$lnK_2 - lnK_1 = \frac{\Delta H }{R} (\frac{1}{T_1}-\frac{1}{T_2})$ . Thus, the graph is not linear.