E-mails exchanged between Norfolk-based scientists in the so-called Climategate affair contain only "candid discussions", a report has said.
The US Environment Protection Agency (EPA) studied every e-mail that had been hacked at the University of East Anglia's Climate Research Unit (CRU).
Sceptics claimed the e-mails undermined the integrity of the CRU, which was later cleared of any wrong-doing.
The EPA said critics "routinely misunderstood the scientific issues".
The agency, which is part of the US government, added in a report that those who attempted to interpret the e-mails came to "faulty scientific conclusions" and "resorted to hyperbole."
They also "impugned the ethics of climate scientists and characterised actions as falsifications and manipulation with no basis for support," the EPA continued.
"Petitioners often cherry-pick language that creates the suggestion or appearance of impropriety, without looking deeper into the issues."
There have been three reports into the affair, which was triggered when e-mails were leaked in December last year.
The third and final independent review by Sir Muir Russell was commissioned by the university following the hacking of e-mails from its servers.
In July, the review concluded the rigour and honesty of scientists at the CRU was not in doubt.
However, it did criticise the university's climate scientists for their lack of openness with regard to complying with Freedom of Information requests.
It also said the CRU was too quick to dismiss critics from outside its own circles.