In a statement Friday, the ministry said the pact was ratified in a ceremony at the UN headquarters in New York, according to the Associated Press.
The Paris deal calls for keeping global temperature increases below 2 degrees Centigrade (3.6 degrees Fahrenheit) compared with preindustrial times.
Pakistan committed to the accord in April.
Climate change in recent years has caused deadly heatwaves in Pakistan's southern Sindh province. Earlier this month, the city of Lahore was engulfed in heavy smog for several days.