A National Science Foundation investigation is the latest to clear a Penn State University climate scientist of misconduct related to leaked emails discussing global warming.
The independent federal agency found no evidence of wrongdoing by meteorology professor Michael Mann in a report earlier this month.
Hackers in 2009 released emails between researchers, including Mann, that critics claimed were evidence of scientists hiding evidence and overstating the case for manmade global warming.
But the NSF says there's no evidence Mann's data was fabricated or his results falsified, despite "significant critical examination."
University Vice President for Research Henry Foley said in a statement Tuesday the NSF report "clearly exonerates" Mann.
The university also cleared Mann after two related investigations.