So first we need to scale Kai's height, this should be fairly easy.
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Po's Height - 1.8796 meters or 330.61 px
Line 1 - 78.26 px
Line 2 - 101.87 px
Line 3 - 410.48 px
410.48+101.87+78.28 = 590.63 px
590.63/330.61 = 1.7865x taller
1.8796*1.7865 = 3.3579 meters
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Kai Height - 3.3579 meters or 40.25 px
3.3579/40.25 = 0.0834 meters/px
Base Width 1 - 43.57 px
This was 43 pixels wide and it went 7 pixels down so that's 0.1628 pixels down per width-pixel, to keep the scaling consistent.
Base Width 2 - 280.63 px
Height 1 - 129.27 px
Height 2 - 270.8 px
43.57+280.63 = 324.2 px base
129.27+270.8 = 400.07 px height
324.2*0.0834 = 27.0383 meters
400.07*0.0834 = 33.3658 meters
Modelling this as a cylinder.
27.0383/2 = 13.5192 meter radius
(3.14)(13.5192^2)(33.3658) = 19,158.14 m^3
19,158.14 m^3 = 19,158,100,000 cm^3
Now the pillar is pretty obviously fragmented.
19,158,100,000*8 = 153.3 Gigajoules
Results
Kai's Ki Power - 36.63 Tons, City Block level
Sources
Po's Height - http://kungfupanda.wikia.com/wiki/Po#cite_note-officialsite-1