Scientists have found an unlikely source of greenhouse gases and that too a huge one in the form of world’s reservoirs – a source that is said to be producing a massive 1 gigaton of carbon dioxide a year.
The claims have been put forward by scientists at Washington State University through a study published in journal BioScience. The study says that the amount of carbon dioxide produced by the reservoirs around the world is 1.3 per cent of all greenhouse gases produced by humans. Beyond the carbon dioxide, these reservoirs are also said to be producing methane, which is more potent a greenhouse gas than carbon dioxide. The amount of methane produced by world’s reservoirs is comparable to the amounts produced by rice paddies or biomass burning. So much so that acre per acre, reservoirs emit 25 percent more methane than previously thought.
Methane has always been thought as being a major contributor to the global warming impact that greenhouse gases have on the planet. And rightly so because methane contributes to around 80 percent of the total global warming impact of all those gases from reservoirs, the scientists involved with the study reveal.
Reservoirs undoubtedly have been seen as one of the green sources of energy beyond other services such as flood control, navigation and water supply for agriculture among other things, but studies have been indicating that these reservoirs might not be as green as we once thought. Increased number of studies are being undertaken to look at the impact of reservoirs on environment because there have been evidence that these man-made constructions are effectively altering the ecosystems in the area.
Unlike natural water bodies, reservoirs tend to have flooded large amounts of organic matter that produce carbon dioxide, methane and nitrous oxide as they decompose. Reservoirs also receive a lot of organic matter and “nutrients” like nitrogen and phosphorous from upstream rivers, which can further stimulate greenhouse gas production
The authors also report higher per-area rates of methane emission from reservoirs than have been reported previously. This means that acre-for-acre the net effect of new reservoirs on atmospheric greenhouse gases will be greater than previously thought. Reservoir construction around the globe is expected to proceed rapidly in coming decades.