The good news is global and local. Keeping inland lakes from turning green means less greenhouse gases entering the atmosphere and contributing to climate change. Healthy drinking water, fishing and recreation opportunities are also increased when waters are not green.
What’s wrong with being green? Toxins released by algal blooms can ruin drinking water. When dense algae blooms die, the bacteria that decompose the algae also deplete oxygen in the water. Without oxygen, fish and other animals suffocate. Globally, such green waters are also an important contributor to atmospheric methane — a greenhouse gas that is up to 34 times more potent than carbon dioxide.
“We estimate that the greening of the world’s lakes will increase the emission of methane into the atmosphere by 30 to 90 percent during the next 100 years,” said Jake Beaulieu of the United States Environmental Protection Agency and lead author of a paper on lake greening and greenhouse gas emissions published March 26, 2019 in the journal Nature Communications.