Scientists are human, especially medical/pharmacological scientists

Daniele Fanelli of the University of Edinburgh finds that 2% to 14% of scientists have "fabricated, falsified or modified data or results at least once":

The frequency with which scientists fabricate and falsify data, or commit other forms of scientific misconduct is a matter of controversy. Many surveys have asked scientists directly whether they have committed or know of a colleague who committed research misconduct, but their results appeared difficult to compare and synthesize. This is the first meta-analysis of these surveys. ....

A pooled weighted average of 1.97% (N = 7, 95%CI: 0.86–4.45) of scientists admitted to have fabricated, falsified or modified data or results at least once –a serious form of misconduct by any standard– and up to 33.7% admitted other questionable research practices. In surveys asking about the behaviour of colleagues, admission rates were 14.12% (N = 12, 95% CI: 9.91–19.72) for falsification, and up to 72% for other questionable research practices.

The problem varied by discipline with reports of misconduct appearing most frequently among "medical/pharmacological researchers."

I suspect that, when all the results are in, it will also be found that global warming has an exception amount of scientific fraud.