In Cambodia, a case for localizing climate-change research

In Cambodia, a case for localizing climate-change research

Researchers know global temperatures are rising. Now scientists from as far away
as Finland are studying what that means for the 1 million floating residents of
the Tonle Sap Lake.

By David Montero | Correspondent of The Christian Science Monitor / June 6, 2008
edition

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Reporter David Montero discusses the idea of studying climate change on a local
level.
Nam Lai, a carpenter in this remote corner of Cambodia, remembers when it was
easy to park his movable houseboat on the Tonle Sap Lake where he lives. But
now, it’s getting harder to find a suitable spot for his small barge. “I have to
move the house farther and farther from the shore,” he says.

For years, the 1 million inhabitants of the lake – Southeast Asia’s largest
freshwater body – have lived a mobile existence to keep step with the seasonal
ebbs and flows brought on by monsoons and melting Himalayan snows that expand
the lake to five times its normal size. But many villagers say the deeper waters
needed to park their houseboats are harder to find as the summers get hotter and
the lake’s water level drops.

Lai’s observations, together with evidence of climate change’s impact on other
fisheries around the world, has scientists deeply concerned that Tonle Sap Lake
– one of the world’s most fragile ecosystems and one of its most productive
fisheries – is also under threat. The lake is essential to Cambodia’s food
supply, its fish providing 60 percent of the country’s protein, while supporting
the livelihoods of about 12 percent of its people.

The problem is, nobody knows the impact of climate change for sure – even the
teams that have come to find out from as far away as Finland – since scientific
inquiry has only just begun. Observers say that the uncertainty underscores that
better understanding of local scenarios, not just global modeling that looks at
steady increases in world-wide temperatures, is needed to pinpoint climate
change’s impact on people and livelihoods.

“There’s a whole area of science that needs to relate climate and physical
change to people and social changes – to identify relationships between physical
changes and social consequences,” says Eric Baran, research scientist at the
Phnom Penh office of the World Fish Center, a research organization
headquartered in Malaysia.

The Cambodian government has begun looking at the problem, creating a
climate-change office in 2003 and undertaking a climate-change vulnerability
assessment in 2001. But neither of those measures has focused specifically on
the Tonle Sap Lake. Some pioneering studies, including one at Africa’s Lake
Tanganyika, have linked some of the same problems the Tonle Sap is exhibiting –
such as reduced fish yield – to climate change. But it’s not yet clear whether
climate change or other factors are responsible here.

Whatever the cause, floating gas-station owner Sinan San has seen the effects
firsthand. Her main customers – fishermen – are no longer able to make good
catches, and her earnings have dried up since 2004.

“The number of fishermen has decreased because there are less fish, and they
move to upland for their livelihood. They say fish are getting smaller and
smaller,” she says. Scientists agree, saying overfishing, poor management, and
unfair laws have led to a sharp decrease in the number and size of the lake’s fish.

“Small fish are more susceptible to climate fluctuations,” says Mr. Baran. “If
the year is good, you have many [small fish]. If the year is bad, you have
nothing. This will make the system more and more shaky.”

The declining fish are just one variable in a host of factors that threaten to
affect the lake’s hydrology, further exposing it to the risks of climate change.

“Many factors will have impacts on the hydrological regime of the Mekong Basin
and on the Tonle Sap Lake’s ecosystem,” Timo Menniken, an adviser to the Mekong
River Commission Secretariat in Vientiane, Laos, writes in an e-mail. “These
include general rapid economic development, the ongoing development of
hydropower schemes along the upper reaches of the Lancang-Mekong, the proposed
development of hydropower schemes on tributaries and the mainstream in the lower
basin, the indications of groundwater depletion and water pollution caused … by
the tourism industry, and plans for oil exploration in the Tonle Sap Basin.”

Another factor is accelerated glacier runoff. “The hydrology can be affected by
the melting away of mountain snows in Tibet. You may see water levels rise,
which would cause salinity levels to rise,” says Neou Bonheur, the project
director of the Ministry of Environment’s Tonle Sap Environment Management
Project. “We just don’t know. There are a wide range of areas that we need to
set up and observe.”