There were huge numbers of beaver in North America before they were heavily trapped. And the CO2 in the atmosphere was stable at 280 ppm. Notice that the article stated that the dams produced both sinks and sources of carbon. Could potentially release about 820,000 tons of carbon annually? We humans put over 40 billion tons of carbon into the atmosphere annually. That is 820,000 tons versus 40,000,000,000 tons. Anything else, dumbass deniers?