GLOBAL WARMING COULD SEVERELY HIT ASIA’S
STAPLE, RICE SAY RICE SCIENTISTS
Professor Kenneth Cassman
By Walter Jayawardhana
reporting from Los Angeles
Rice, the king of all grains and essential staple of millions of Asians
including Sri Lankans is being hit by the much feared global warming
contributed mostly by industrial nations of the West, rice scientists
said.
The new study that indicates that Asia’s staple could take a
severe beating in the much talked about ‘global warming’ was
performed at the world’s premier rice research farms, the International
Rice Research Institute, in the Philippines by an international team
of scientists.
Shaobing Peng and his colleagues analyzed rice production and weather
data spanning quarter of a century kept at the institute’s farm
in the Philippines and discovered that during that time there was an
average increase about three quarter of a degree of a Celsius. They
said, this increase was recorded during the nights.
Kenneth Cassman , the research team member from the United States
said the higher night time temperatures caused by the global warming
caused the rice plants to work harder during night times that affected
directly to the decrease in the rice yields.
He was quoted as saying, "And what happens then is that diverting
energy to maintain important metabolic functions that keep the plant
alive during the nighttime diverts energy away from producing biomass
and grain yield."
Explaining the dramatic effects of the temperature increase, the American
scientist said for each one degree increase during night time the rice
yield fell by ten per cent.
Professor Cassman who is also attached to the University of Nebraska
further said, "The elevated temperature, we believe, increases
what we call the 'maintenance respiration costs' of the plant at night.
That is, the amount of energy the plant needs to use to keep itself
alive during the nighttime."
The rice grown for here from which the data had been taken for the
research had been done under the best and controlled growing conditions
the rice scientist said.
Explaining the above he said, "So that the yields aren't limited
by weeds or insects or diseases or nutrient deficiencies or water -
too much water, too little water - so that year in and year out, the
only thing that determines the yield of that crop is the amount of solar
radiation and the temperature."
Cassman said earlier studies using only computer simulations indicated
the same results of declining rice yields with a warmer temperature
but this real world research not only confirmed the earlier results
but showed the effect could double of what the simulations indicated.
"Our study shows that the magnitude of the yield decrease due
to increasing night temperatures that we measured from the field studies
was double the rate of decrease predicted by computer simulation models,"
he concluded.
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