More than half of the world’s lakes and two-thirds of its rivers are drying up, threatening ecosystems, farmland, and drinking water supplies. Such diminishing resources are also likely to lead to conflict and even, potentially, all-out war.
The situation is beyond dire. In 2023, it was estimated that upwards of three billion people, or more than 37% of humanity, faced real water shortages, a crisis predicted to dramatically worsen in the decades to come. Consider it ironic then that, as water is disappearing, huge dams — more than 3,000 of them — that require significant river flow to operate are now being built at an unprecedented pace globally.
[Recent] research suggests that hydro-powered dams can create an alarming amount of climate-altering greenhouse gas emissions. Rotting vegetation at the bottom of such reservoirs, especially in warmer climates (as in much of Africa), releases significant amounts of methane, a devastating greenhouse gas, into the atmosphere.
“We estimate that dams emit around 25% more methane by unit of surface than previously estimated,” says Bridget Deemer of the School of Environment at Washington State University in Vancouver, lead author of a highly-cited study on greenhouse gas emissions from reservoirs. “Methane stays in the atmosphere for only around a decade, while CO2 stays several centuries, but over the course of 20 years, methane contributes almost three times more to global warming than CO2.”