India, April 22 -- "Come rain or shine, we have to do farming," said Makhan Lal, a cane grower from Shamli, a fertile belt about 100 km from the national capital. "We can't afford to skip a season."

Cultivators in India's food-bowl states, such as Uttar Pradesh, are worried about an El Niño event, a weather glitch that could appear in the second half of the monsoon season and reduce rainfall around July, the peak month for summer planting in India, the world's largest exporter of rice and an agricultural powerhouse.

Scientists are fairly sure the weather phenomenon, marked by higher sea surface temperatures, will ripple around the globe this year, bringing dry summers in South Asia and flooding in South America. El Niño trigge...