Dams are major driver of global environmental change

Posted: 17 May 2017 06:05 AM PDT

Water reservoirs created by damming rivers could have significant impacts on the world’s carbon cycle and climate system that aren’t being accounted for, a new study concludes…[the study] found that human-made dam reservoirs trap nearly one-fifth of the organic carbon moving from land to ocean via the world’s rivers.

While they can act as a significant source or sink for carbon dioxide, reservoirs are poorly represented in current climate change models. “Dams don’t just have local environmental impacts. It’s clear they play a key role in the global carbon cycle and therefore Earth’s climate,” said Philippe Van Cappellen, a Canada Excellence Research Chair in Ecohydrology at Waterloo and the study’s co-author. “For more accurate climate predictions, we need to better understand the impact of reservoirs.”

There are currently in excess of 70,000 large dams worldwide. With the continuing construction of new dams, more than 90 per cent of the world’s rivers will be fragmented by at least one dam within the next 15 years….

Taylor Maavara, Ronny Lauerwald, Pierre Regnier, Philippe Van Cappellen. Global perturbation of organic carbon cycling by river damming. Nature Communications, 2017; 8: 15347 DOI: 10.1038/ncomms15347