The house is on fire. You hurl what appears to be water, but the fire burns all the more fiercely.

That's the promise of hydropower. On first look, it offers an answer to global warming. "Clean and green," proponents say. But research shows tropical dams emit more greenhouse gases (GHG) than first thought, and the pattern of net emissions defeats any perceived gain in green energy.

And when you factor in the GHG from roads, cement manufacture, and the release of carbon by the required deforestation, the average tropical dam may emit more gases than coal-fed plants of equivalent output.

What's more, dams occupy land that's badly needed for other purposes, especially in times of increasing food insecurity. This is all the more acute in nations where these resources are already scarce.

Take Laos, a small nation with its largely low energy-using rural population, and hard-line government.

Laos has abundant rivers, but only about 8 to 10 percent of its territory is arable land. Most is sloping rocky escarpments with thin friable soils. The good soils are on the river flats, easily watered; annually replenished by rains and increasingly inundated by dams.

Climate change adaptation strategies highlight food and water security as being primary concerns. It appears counter-intuitive to lose both to nominal increases in GDP.

China is particularly involved in the spate of dams that have sprung up across Laos and other Southeast Asian countries. Over half of the new proposed dams across the Mekong River and its tributaries in Laos have some Chinese stake.

It's understandable that China wants to get involved in projects that seem to both promise economic development, and consequent goodwill and markets, and will also turn a profit. But the ecological cost may not be outmatched by economic gain, and the damage done by unpopular projects to China's image won't be easily alleviated.

Recent reports question the mantra that dams will "alleviate poverty." They conclude that there is little evidence that dams benefit the poor, concluding that conversely the loss of agricultural lands and aquatic resources are driving many rural people into deeper poverty.

Planners in city offices continue to pore over maps searching for land to replace that to be flooded. But as one Indonesian farmer told me, "Land is like your wife. It takes many years to really get to know her."

Yes, there are guidelines and regulations to make it kosher, but as one environmental scientist said to me, "It's never the rich who have to move, who have their churches, golf courses and homes drowned. The rich get the power, while the poor get the pain."

If governments and corporations were more truthful, it might be easier to gauge how much power is really needed and who benefits.

The Nam Ou Cascade, threatening to drown one of Lao's most popular tourist destinations in concrete, is one of the more egregious examples.

The population density of the region is less than 10 people per square meters. We are told the power from six dams to be built by Sinohydro is meant to be for them.

But will displacement and the destruction of natural beauty really be compensated for by electricity for the poor? Or will it reach the already energy-guzzling big cities and power elites?

With the controversy over its own Three Gorges Dam still well within public memory, China should think twice before committing too heavily to projects that may bring more harm than good to the regions they're meant to aid.

The author is a member of the Society of Environmental Journalists currently based in Jakarta. opinion@globaltimes.com.cn