Kuala Lampur, Nov. 3 -- Ask any Malaysian cook why a plate of nasi campur costs more than it did a few years ago, and the answer will rarely begin with the weather. It should. Every northeast monsoon, flooded fields in Johor, Perak and Kelantan push up wet market prices within weeks, and those prices travel into every kitchen in the country, from the home stove to the school canteen.

Extreme weather is no longer just a weather story. It is a food security story, and increasingly a national security one. At its centre is the food service sector: the restaurants, mamak stalls, hospitals and schools that feed Malaysians outside the home. This is where rising ingredient costs are quietly turned into smaller portions, cheaper substitutes and ...