STATE COLLEGE, Pa. -- A Penn State professor said he welcomes the school's investigation into e-mails he sent about global warming that are at the center of an international controversy.

Hackers recently breached servers at a research center in London, stealing thousands of pieces of correspondence and posting the information on the Internet.

The e-mails cover more than a decade of communication between leading scientists, including Penn State meteorology professor Michael Mann. His research has been criticized by global warming skeptics.

Congress held a heated hearing Wednesday on the e-mails and Penn State has launched an inquiry into the matter.

Mann denies any wrongdoing and said his e-mails are being taken completely out of context.