Article: Thanks partly to NOAA’s new adjusted dataset, tommorrow they’ll claim to reporters that May was the ‘hottest ever’

So for May 2015 NOAA says the globe is at 0.87°C above normal, and UAH [satellite data] says the globe is at 0.27°C above normal –  a difference by a factor of three.

So, again, I ask the question: If global warming is true and obvious, why is necessary to lie by adjusting the data up?