know global temperatures are rising. Now scientists from as far away as
million floating residents of the
factors will have impacts on the hydrological regime of the
and on the
Mekong River Commission Secretariat in
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
carpenter in this remote corner of
remembers when it was easy to park his movable houseboat on the
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.
the 1 million inhabitants of the lake –
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.
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
supply, its fish providing 60 percent of the country’s protein, while
supporting the livelihoods of about 12 percent of its people.
is, nobody knows the impact of climate change for sure – even the teams that
have come to find out from as far away as
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.
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
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
one at Africa’s Lake Tanganyika, have linked some of the same problems the
climate change. But it’s not yet clear whether climate change or other factors
are responsible here.
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.
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.
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.”
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.