Stanford, California
May 2, 2007
Rice farming in Indonesia is
greatly affected by short-term climate variability and could be
harmed significantly by long-term climate change, according to a
new study by researchers at
Stanford University, the
University of Washington and the
University of Wisconsin. The
results are scheduled for publication the week of April 30 in
the online edition of the journal Proceedings of the
National Academy of Sciences
(PNAS).
"Agriculture is central to human survival and is probably the
human enterprise most vulnerable to changes in climate," said
lead author Rosamond Naylor, director of the Program on Food
Security and the Environment at Stanford. "This is particularly
true in countries such as Indonesia, with large populations of
rural poor. Understanding the current and future effects of
changes in climate on Indonesian rice agriculture will be
crucial for improving the welfare of the country's poor."
Indonesia—the fourth most populous country in the world and one
of the biggest producers and consumers of rice—is characterized
by a population of rural poor who depend on rice agriculture for
their livelihood, she added.
Hungry season
In the study, the researchers looked at the impact of climate on
Indonesian rice farming since 1983. Indonesia has two rice
harvests—the main harvest in December and January and a smaller
one in late spring. Because summers are dry, rice stocks often
diminish and prices rise in the autumn, which Indonesians call
the "hungry season." Planting for the main harvest usually
begins in October with the coming of the monsoon rains.
The researchers found that rice production since 1983 has been
greatly affected by year-to-year climate variability—especially
El Niño/Southern Oscillation events, which occur in the Pacific
Ocean every two to seven years. During a warm El Niño, the
arrival of the monsoon rains is delayed, prolonging the hungry
season and disrupting the planting of the main December-January
crop.
"During a bad El Niño event, farmers literally wait months
before they can plant their crop, resulting in a harvest that is
months late and often much smaller in size," Naylor said.
Climate change
After analyzing the recent record, the researchers focused on
how climate change could affect rainfall and agriculture in
Indonesia in the next 50 years. Using output from 20 global
climate models tailored to the complex local topography of the
Indonesian archipelago, the authors found that the probability
of experiencing a harmful delay in monsoon rains could more than
double in some of the country's most important rice-growing
regions.
"Most models predict that the rains will come later in
Indonesia, that it will rain a little harder once the monsoon
begins and then it will really dry up during the summer months,"
said study co-author David Battisti, an atmospheric scientist at
the University of Washington. "So Indonesia could be looking at
a much shorter rainy season, with an almost rainless dry season
in some areas, squeezing rice farmers on both ends."
While the study did not address how climate change could affect
the frequency or intensity of El Niño events in the future, the
authors concluded that even if there were no changes in the
current El Niño pattern, Indonesian rice growers will face a
significantly shortened rainy season. In the absence of adaptive
measures, rice growers could suffer greatly, they said.
Adapting for change
What adaptive measures could be taken in the face of harmful
short-term variability and long-term change in climate?
"In the short run, the science of El Niño prediction has
advanced to the point that reasonably high-confidence forecasts
are available at least two seasons in advance," said study
co-author Marshall Burke, manager of the Program on Food
Security and the Environment. "We have developed a forecasting
model that's now being used by the Indonesian Agricultural
Ministry to anticipate and plan for El Niño events and their
effects on agriculture."
The authors also are working with Indonesian officials to
develop longer-run strategies that address the anticipated
effects of climate change on agriculture in the country. "Such
strategies could include investments in water storage,
development of drought-tolerant crops and crop diversification
for those farmers at greatest risk," Burke added.
"To our knowledge, our study is the first climate-agriculture
study that uses projections from all available global climate
models to look at climate effects in a specific region,"
Battisti said. "Thus, more than past efforts, our study captures
the range of uncertainty across different projections of future
climate, knowledge which will be crucial for long-run thinking
about how to respond."
Added Naylor: "From a scientific perspective, it's imperative
that we now replicate this kind of study elsewhere in order to
start building a more complete picture of the effects of climate
change on agriculture." The researchers are conducting a similar
study in China, she added.
Other co-authors of the PNAS study are Walter Falcon,
co-director of the Stanford Center for Environmental Science and
Policy, and Daniel Vimont, assistant professor of atmospheric
and oceanic sciences at the University of Wisconsin. The study
was funded by the National Science Foundation. |
|
Assessing the Risks of
Climate Variability and Climate
Change for Indonesian Rice
Agriculture
Scheduled for online publication
in PNAS during the week of April
30 at
http://www.pnas.org/. |
|