What was found
CREW REPORTED INITIALLY ON TAKEOFF ROLL & CLIMB OUT, AIR FLOW VOL INCREASED & FLIGHT DECK TEMPERATURE INCREASED. PLACED LT PACK IN STANDBY COLD & TEMPERATURE & AIR FLOW VOL RETURNED TO NORMAL. FLIGHT ATTENDANTS & PAXS THEN REPORTED LOUD & CONTINUOUS POPPING SOUND, FOUND INTERIOR SIDEWALL BUCKLED IN SEVERAL AREAS. EMER DECLARED FLIGHT RETURNED & LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE & FERRIED FOR MX. REPLACED BOTH RT & FWD LT RISER DUCTS.