Complex sentence: Mann received a personalized certificate from the IPCC for "contributing to the award of the Nobel Peace Prize for 2007 to the IPCC" that included a photo image of the Nobel Diploma awarding the Nobel Peace Prize to the IPCC, jointly with Al Gore.
Split into simpler sentences: Mann received a personalized certificate from the IPCC for "contributing to the award of the Nobel Peace Prize for 2007 to the IPCC". The certificate included a photo image of the Nobel Diploma and the Nobel Peace Prize was awarded jointly to the IPCC and to Al Gore.