A recent study referred to by some as a Doomsday Report suggests that rising sea levels could flood three times more land than previously predicted.
In Southeast Asia, if the study proves accurate, parts of Ho Chi Minh City and Bangkok could be underwater by 2050. Millions of people in Vietnam's Mekong Delta could be forced to flee coastal areas.
The study prepared by a United Nations Intergovernmental Panel on Climate Change (IPCC) was issued in late September.
According to Eugene Linden, who has written widely on climate change, for years most scientists saw climate change as a distant prospect. But they were wrong.
Rising sea levels have been driven by greenhouse gas emissions, climate change, and an accelerating pace of ice melting in the Arctic and Antarctica.
In a commentary on two new books dealing with climate change, epic storms, and rising seas, Emily Raboteau notes that the West Antarctic ice sheet is collapsing sooner and faster than predicted. She also makes it clear in an essay written for The New York Review of Books that poor people are the biggest losers when the sea rises and tidal waves strike.
Raboteau is discussing the situation in coastal areas of the United States. But she could easily be speaking of the rural poor living along coasts and rivers in Southeast Asia where many could be impoverished after tidal waves hit them.
The new IPCC report corrects previous satellite elevation data and asserts that coastlines are much more exposed to rising sea levels than was previously believed.
The report says that previous sea level-rise scenarios have underestimated land loss and population displacement by about a third.
Nonetheless, while acknowledging that the IPCC report was done by serious researchers, some scientists maintain that the report presents a worst-case scenario that must be checked against their own data.
Eight Asian nations�China, Bangladesh, India, Vietnam, Indonesia, Thailand, the Philippines, and Japan�account for some 70 percent of the people living on at risk land, according to The Washington Post.
Widespread, destructive flooding
The IPCC report, which was prepared by more than 100 scientists from more than 80 countries, relies on a new model for assessing the situation.
The report says that Even with deep cuts to carbon emissions Bangladesh, Vietnam, and Thailand by the end of the century face high tides
Continued high emissions with Antarctic instability could entail land currently home to one-third of Bangladeshis and Vietnam's people falling below the high tide line, the report says.
It adds that some municipal populations will see even higher proportions.
Ho Chi Minh City, which is located in the Saigon Delta and close to the Mekong Delta, already faces annual flooding due to a combination of storms, heavy rainfall, and upstream discharges from reservoirs.
Still frequently referred to by residents by it pre-communist era name of Saigon, Ho Chi Minh City is one of the most rapidly growing cities in Southeast Asia. With a population of about nine million, it's the most highly populated city in Vietnam and hosts much of the country's industry and commerce.
According to the website AGU100, the city generates 21 percent of Vietnam's Gross Domestic Product (GDP). So the stakes are high.
Defenses against flooding
According to the online Vietnamese newspaper VnExpress, Ho Chi Minh City is planning to spend U.S. $345 million on anti-flood projects this year. These would cover the downtown area and part of the suburbs.
The city is also discussing the possibility of constructing a Thames Barrier-type river barrage to contain any major flooding.
Along the banks of the 2,700-mile-long Mekong River which flows through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam, the stakes are also extremely high.
More than 60 million people depend on Southeast Asia' longest river for food and transportation. According to some accounts, the Mekong's waters support the world's most productive inland fishery. For many, the river's fish provide their main source of protein.
Meanwhile, a number of factors�all man-made�have contributed to the sinking of land in the Mekong Delta, which is Vietnam's main source of rice and the home to 18 million people.
Upstream hydropower dams in China and Laos have blocked much of the sediment that once reached the Delta. The sediment has replenished the Delta with nutrients needed for agricultural crops. It has also reinforced river banks.
On June 19, Brian Eyler, a leading expert on the Mekong River, in a paper co-authored with Jake Brunner of the International Union for Conservation of Nature (IUCN) in Hanoi, documented how this loss of sediment would affect the Delta.
The two warned that without sufficient sediment to replenish the land, the delta will sink beneath the East Sea�a problem compounded by unsustainable groundwater pumping and a rising sea level.
Vietnam has benefited from advice on how to deal with looming challenges from experts such as Eyler and from international organizations such as the United Nations Development Fund (UNDP), as well as from hydrological experts from the Netherlands.
Eyler and Brunner suggested that Laos and Cambodia could address Vietnam's concerns by prioritizing dams that minimize the downstream impact on Vietnam while expanding their use of non-hydro renewable energy sources such as solar and wind power. It helps that the costs of solar and wind power have fallen in recent years.
Vietnam, for its part, could invest in a national electricity grid in Laos that allows Laos to charge transmission fees. Working together, Vietnam, Cambodia, and Laos could meet projected demand for electricity while lowering costs.
But according to a recent article by Sam Geall published by Foreign Affairs magazine on Nov. 7, China's construction of at least 10 hydropower dams on the main trunk of the Mekong have begun to negatively affect fisheries, riverbank gardens, and farms downstream.
Now Beijing is helping to accelerate dam building construction in the downstream nations of Laos and Cambodia, making the Mekong a major area for the projections of Chinese interests in Southeast Asia, says Geall, who is a China expert and research fellow at the University of Sussex in the United Kingdom.
In summary, the Geall says, The communities that depend on the Mekong find themselves at the nexus of seemingly implacable forces: the consequences of climate change, the geopolitical ambitions of China, and the indifference of their governments.
On the positive side, Geall says that against immense odds, residents of the Mekong basin are developing ways to protect their livelihoods and to safeguard the river from ruin.
Meanwhile, to the west of Vietnam, Thailand faces uncertainties due to climate change and rising waters similar to those challenging Vietnam.
Bangkok's rising water levels
The writer Ron Gluckman says that Bangkok might seem a surprising addition to the climate change challenge.
As he notes, media coverage more often focuses on the impact of rising sea levels on Thailand's coastal areas or low�lying islands, Gluckman wrote in an article published on the website urbanland.
But the effects are felt inland, along rivers and deltas, mainly in the Chao Phaya River region, he says, and Bangkok is particularly vulnerable. It is a city of canals, situated barely above sea level. By some measures, it has already sunk below sea level.
Gluckman describes the Thai capital, with a population of more than 10 million, as among the world's fastest sinking cities.
According to the website phys.org, Bangkok is built on once-marshy land about 1.5 meters (about four feet) above sea level and is projected to be one of the world's hardest hit areas, alongside the Southeast Asian cities of Jakarta and Manila.
Nearly 40 percent of Bangkok will be inundated by as early as 2030 due to extreme rainfall and changes in weather patterns, according to a World Bank report.
Shrimp farms and other aquaculture development not far from Bangkok that have replaced the mangrove swamp forests that used to protect against storm surge have caused significant erosion of the coastline near the capital.
Phys.org says that the Thai government is scrambling to mitigate the effects of climate change by constructing a canal network of up to 2,600 kilometers (1,616 miles) of pumping stations and eight underground tunnels to evacuate water if disaster strikes.
In 2017, Chulalongkorn University in central Bangkok built an 11-acre park especially designed to drain several million liters of water and redirect it so that surrounding neighborhoods aren't flooded.
But a representative of the nonprofit environmental organization Greenpeace says that Bangkok needs more green spaces. He adds, however, that environmentalists are less influential than building developers.
Or as he put it, the environmentalists are outweighed by building developers.
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