The Institute of Physics said 'worrying implications' had been raised after it was revealed the University of East Anglia had manipulated data on global warming.
The rebuke - the strongest yet from the scientific community - came as Professor Phil Jones, the researcher at the heart of the scandal, told MPs he had written 'some pretty awful emails' - but denied trying to suppress data.
The Climategate row, which was first revealed by the Daily Mail in November, was triggered when a hacker stole hundreds of emails sent from East Anglia's Climatic Research Unit.
They revealed scientists plotting how to avoid responding to Freedom of Information requests from climate change sceptics.
Some even appeared to show the researchers discussing how to manipulate raw data from tree rings about historical temperatures.
In one, Professor Jones talks about using a 'trick' to massage figures and 'hide the decline'. Read more.