From: Tom Gray <tgray@igc.apc.org>
Newsgroups: sci.environment
Date: 13 Oct 92 05:28 PDT
Subject: IPS: Rice and Global Warming
Nf-ID: #N:cdp:1466601807:000:4343
Nf-From: cdp.UUCP!tgray    Oct 13 05:28:00 1992


/* Written 12:46 am  Oct  3, 1992 by newsdesk@igc.apc.org in igc:ips.englibrary */
/* ---------- "ENVIRONMENT: Growing more rice will" ---------- */
Copyright Inter Press Service 1992, all rights reserved.  Permission to re-
print within 7 days of original date only with permission from 'newsdesk'.

Title: ENVIRONMENT: Growing more rice will add to global warming


manila, sep 30 (ips) -- the world needs more rice to feed its
swelling population, but increasing harvests will release
more methane into the atmosphere, warming the earth's climate.

scientists say paddy fields, which grow 95 percent of the
world's rice, emit about a quarter of the methane released every
year.

although atmospheric concentration of this greenhouse gas is
less than one percent that of carbon dioxide (co2), methane may
cause 15 percent more global warming, says dr h u neue,
coordinator of methane research at the international rice
research institute (irri) in los banos, 60 km south of manila.

this is because a single methane molecule traps heat about 30
times more effectively than a co2 molecule, he explains.

''but farmers can't quit growing rice to reduce methane
emissions,'' says neue. ''rice is the world's most important food
crop. it provides more than half the daily food for one of every
three persons on earth.''

''our objective is to reduce those emissions. but first, we
must learn more about the process.''

various technologies have been proposed to cut down methane
emissions, but scientists need to conduct more field research to
determine the most technically and socio-economically feasible
methods.

over the next five years, the united nations development
programme (undp) will contribute five million dollars from the
global environment fund (gef) for such a project, to be carried
out by irri.

flooded rice fields in china, india, indonesia, the
philippines and thailand have been identified as key sites for
the research project, based on the global distribution of
harvested rice lands.

the programme will focus on developing and standardising
equipment and methods for studying methane emissions, and will
train experts in collaborating national agricultural research
centres.

methane is produced by decaying vegetation in rice paddies.
up to 80 percent of the emitted gas enters through the roots and
moves up the plant, which acts like a chimney.

smaller amounts of methane rise up to the water surface or
diffuse slowly from the soil through the water. most diffused
methane, however, is broken down in the soil and floodwater and
never reaches the atmosphere. (more/ips)


environment: growing (2)

''we're interested in the how and why of methane emissions
from flooded rice fields,'' says hugo denier van der gon,
research fellow from wageningen agricultural university in the
netherlands.

''we don't want to change the system without first
understanding it,'' he adds.

but scientists agree that eventually something in the system
must change.

''changing from irrigated lowland rice cultivation to dry
upland farming won't solve the problem,'' says neue. ''even
without rice cultivation, much of the wetland areas would be
naturally flooded.''

''methane emission is a natural process in flooded soils...
our aim is not to decrease methane production, but to decrease
methane emissions,'' he stresses.

increased methane oxidation in rice soils means less gas can
escape, says neue. some rice varieties bring in more oxygen than
others and are thus better methane oxidisers.

''we need a plant with both high oxidation power and high
yield potential,'' he says. ''a plant that will help the
environment without endangering farmers' incomes.''

the irri research project will give a big boost to worldwide
efforts to reduce the emission of greenhouse gases.

while most efforts are focused on industrial emissions, the
research programme will provide valuable information on how to
reduce agriculture's contribution to global warming.

the earth is now said to be 0.5 degrees celsius warmer than in
pre-industrial times, and is expected to be at least three
degrees warmer by the end of the next century.

as temperatures rise, sea levels will go up, flooding many of
the world's highly productive areas and threatening the existence
of island nations in the pacific and indian oceans.
(end/ips/en/ag/ln/92)