Beyond 2050, when climate scientists project temperatures might rise to as much as 6.4 degrees C (11.5 degrees F) over 20th century levels, the planet grows "gloomy" for agriculture, said senior research fellow Gerald Nelson of the International Food Policy Research Institute.

The specialists of the authoritative, Washington-based IFPRI said they fed 15 scenarios of population and income growth into supercomputer models of climate and found that "climate change worsens future human well-being, especially among the world's poorest people."

The study, issued here at the annual U.N. climate conference, said prices will be driven up by a combination of factors: a slowdown in productivity in some places caused by warming and shifting rain patterns, and an increase in demand because of population and income growth.

Change apparently already is under way. Returning from northern India, agricultural scientist Andrew Jarvis said wheat farmers there were finding warming was maturing their crops too quickly.

"Unlike the 20th century, when real agricultural prices declined, the first half of the 21st century is likely to see increases in real agricultural prices," the IFPRI report said.

AP