“Why would anyone believe HeartlandDiscovery Institute ?” You shouldn’t!
Nor should you “believe” NOAA. Science is not about believing, NOAA has been “adjusting” temperature records, The Heartland Institute has not.
In fact The Heartland Institute has no record of bending the facts, lying, adjusting, make up graphs or in any way distorting any data.
Wanna see what NOAA has been doing?
Old temperature records adjusted to show lower temperature and after they had been doing that, not once, not twice, but at least 3 times as documented by for example Don Easterbrook. They also took part in Climategate, as you might remember, but feel free to check it with Skeptical Science.
And when they got caught they changed it back, so now the 30′ are back to being the warmest decade again. According to your post i think they might forgot to tell you.
So, who do you think i trust?