Oil and natural gas have made Qatar rich over the past half-century, and the World Cup is part of a coming-out spending spree. Skyscrapers, malls, luxury hotels and apartment buildings, a new airport and subway network — all drenched in air-conditioning, of course — have sprouted, Oz-like, improbably in this place.

There is little life here without air-conditioning. The city hums with the sound of it.

Ahead of the World Cup, some critics have focused on the stadiums. Seven new ones? Air-conditioned? Outdoors? Oh, the excess. Oh, the environment.

Ghani has heard the critics, including the climate concerns. More than half of Qatar’s electrical output goes toward air-conditioning, and while FIFA’s analysis claimed that the World Cup could be carbon neutral, critics doubt that claim, citing everything from new construction in the past decade to the thousands of flights in and out of Qatar during the tournament.

Ghani and World Cup organizers have declined to provide costs or data on the stadiums or the cooling systems.

For 13 years, working mostly in these university labs, Ghani has greeted his task as a mechanical-engineering puzzle — how to keep teams of soccer players, and the tens of thousands of fans assembled to watch them, cool in a place routinely with triple-digit temperatures, as efficiently and unobtrusively as possible.

His quest got attention. A reporter dubbed him Dr. Cool. He does not refer to himself that way.

The overriding concept is simple science: Warm air rises, cool air falls.

Ghani did not need to cool the entire volume of the stadium — just the six feet or so above the ground where athletes played and in the sloping stands where people sat. Apply cool air down low, he figured, straight to the field (for the players) or to each row of seats (for the fans).