Why is Dr. Norman Borlaug often called "the man who saved a billion lives"?

Dr. Norman Borlaug has been called "the father of Green Revolution." He was an American biologist who developed a semi-dwarf, high-yield, disease-resistant wheat varieties. He led the introduction of modern agricultural production techniques along with the launching of such varieties in Mexico, Pakistan and India. Mexico became a net exporter of wheat while Pakistan and India doubled the wheat yields. The collective increases in yield also known as Green Revolution had vastly improved the food security of the nations. Borlaug has been credited for saving over a billion people worldwide from starvation.