At a Cambodian Lake, a Climate Crisis Unfolds

Khmer Circle: Crisis? What crisis?!

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A trifecta of climate change, hydropower dams and illegal fishing are threatening the Tonle Sap, and the people who rely on its fish.

By Abby Seiff

Ms. Seiff is a journalist.

nyt

Sept. 30, 2019

Fishermen unloaded their catch in Chong Khneas, a village on Tonle Sap Lake, last year. The region has been heavily affected by drought.CreditCreditSergey Ponomarev for The New York Times

When I first met Ly Heng in May 2016, the forest behind his house was still smoldering — the remnants of the worst drought to hit Southeast Asia in decades. Heng lived along a small river at the top of Cambodia’s Tonle Sap Lake, in a protected area known for its rich biodiversity. At 45, he had never seen wildfires, and never seen the water level of the lake dip so low. Charred sticks and leaves crunched underfoot while Heng led me through the woodland, recounting his neighbors’ efforts to keep the fire from incinerating their houses.

“This is the first time it’s this dry, and the first time the forest burned up,” he said.

Tonle Sap Lake is the largest body of freshwater in Southeast Asia. Its wetlands support critically endangered species like the Bengal florican; its sediment provides nutrients for croplands; its fisheries are among the largest and most biodiverse in the world.

And it has reached a tipping point. Just three years after the 2016 drought, another hit the region earlier this year. Local and global leaders should agree to stem the mushrooming of environmentally destructive hydropower dams, combat illegal fishing and mitigate the impacts of global warming. If such action is not taken soon, the Tonle Sap’s days are numbered. With it will vanish an ecosystem that has supported millions of Cambodians and their neighbors for centuries.

Like the Mekong River as a whole, Tonle Sap Lake is beset by problems both local and global. In recent years, a trifecta of climate change, overfishing and the creation of new dams has threatened to unmake the Tonle Sap.

Fishers have begged the Cambodian government to crack down on the large-scale illegal fishing that takes place inside the lake’s protected areas. Environmental campaigners have urged a moratorium on the megadams dotting the Mekong and its tributaries. Researchers have suggested investment in energy alternatives such as floating solar panels. In December, the 2019 United Nations Framework Convention on Climate Change will convene in Santiago, Chile; if the concept of a changing climate remains a theoretical in the minds of some Western leaders, it is very much a lived experience on the Tonle Sap.

The lake is fed by an extraordinary hydrological phenomenon called a monotonal flood-pulsed system. A tributary known as the Tonle Sap River stretches from the Mekong to the Tonle Sap Lake, reversing course twice a year to fill and empty the lake. In the rainy season, water surges up into the lake, which expands as much as six times its dry-season size, covering 6,000 square miles. In the dry season, water flows back out of the lake and into the Mekong.

That beating heart movement allows fish to migrate and spawn, and carries nutrients up and downriver. Some 500,000 tons of fish are caught in the lake each year, making up part of a $2 billion fish industry and providing the primary source of protein for most Cambodians.

This year, the rains didn’t arrive in May, or June, or July. They didn’t come until August, borne on a series of storms so powerful that thousands had to be evacuated. The Mekong River reached a grim milestone: It dipped to its lowest levels since modern recording began.

Each time the Mekong reaches a new low, the pulse that keeps Tonle Sap Lake alive slows. This year, according to officials, the water in the Tonle Sap River reversed course in July — about two months late. (Others believe the reversal came even later.) Soon, the only river in the world to reverse seasonally may not switch direction at all.

Over the past three years, I’ve made repeated visits to the lake to chart how people are coping with these changes. The dozens of fishers I’ve spoken with all say the same thing: The fish are smaller, the catch is dropping, and no one is sure if the lake will make it. I met families whose daughters left home for factory jobs in Phnom Penh, and whose sons sneaked into Thailand for plantation labor. I met people who said they had to fish near protected areas, or use nets with tiny holes, or set traps with sticks from the forest, because if they didn’t resort to some form of illegal fishing, they would die. Nearly everyone I met was deep in debt.

“We’re river people,” Ly Heng told me the second time I visited him, in 2017. “When the water is low it affects us. Fishermen catch fish. If the water is low and they can’t — what happens?”

Mekong governments have long insisted that hydropower was necessary to provide electricity to their rapidly developing economies. On the upper Mekong, or Lancang, as it is known in China, megadams dot the river and its tributaries, delivering electricity but blocking sediment and, increasingly during drought years, water from moving downstream. On the lower Mekong, which runs through Myanmar, Laos, Thailand, Cambodia and Vietnam, each nation has embarked on its own dam-building frenzy.

Cambodia’s Lower Sesan 2 dam, located on a critical Mekong tributary, went online last year despite widespread opposition. (The drought was so protracted, of course, that the dam was rendered useless and power cuts roiled the country’s biggest cities for months.) Eleven more dams are planned or in construction for the mainstem of the lower Mekong, and 120 for the tributaries. Should all those dams be built, by 2040 the fish catch will drop by as much as half. While the economic gains of electricity could top $160 billion for the region, the loss of “natural capital” like forests, wetlands and wild fish could cost $145 billion. That drop in the fisheries could come at a price of nearly $23 billion.

Mekong governments can yet turn the tide. The cost of solar and wind power is plummeting. Some researchers believe that within just a few years it won’t make economic sense for investors to put money into hydropower. Others have suggested floating solar panels and micro-hydro dams as alternatives. A decade ago, Vietnam urged a moratorium on building Mekong dams until their impact could be studied. Instead, its upstream neighbors plowed ahead, and the impact is being witnessed in real time. If the Mekong’s role as an ecosystem isn’t given more value, the region will suffer shocks to food security and economic stability — drivers of conflict.

Time is quickly running out. In 2016, the drought brought wildfires to the forests surrounding the Tonle Sap, razing hundreds of thousands of acres of wetlands.

“Since my ancestors were here, since the gods of my father, during the dry season it’s dry in the Tonle Sap. If the water changes following the season it’s fine, but last year it didn’t follow the season,” Heng told me in 2017. “It was the lowest I’ve seen since I was born.”