Do the Great Lakes account for over 20% of the world’s freshwater?

Two of the five Great Lakes — Erie and Ontario — border New York state. And a New York state legislator recently touted the lakes’ importance to the continent’s and the world’s water supply.

New York State Assembly member Patrick Burke, whose Buffalo-area district almost touches Lake Erie, introduced a bill this month that would create a "Great Lakes Bill of Rights" to give residents "a role in the decision-making process regarding current and future projects that impact the ecosystem."

In a press release introducing the bill, Burke wrote that the Great Lakes account for "over 20% of the world’s freshwater and over 80% of North America’s freshwater." 

Official data says Burke is correct. 

Burke’s office did not answer a request for comment.

Besides Erie and Ontario, the Great Lakes include Superior, Michigan and Huron to the west.

According to the U.S. Environmental Protection Agency, the Great Lakes account for 21% of the world’s freshwater and 84% of North America's surface fresh water. That’s in line with what Burke said.

Such percentages may sound like a lot, but Joseph Atkinson, the director for the Great Lakes Program at the University at Buffalo, told PolitiFact that even such large reserves cannot last indefinitely without careful conservation.

"if you start diverting the water from the Great Lakes to other areas of the U.S., depending on how much is moved, they won’t be able to provide as much fresh water as they would if the water remained where it was," Atkinson said. If the water being removed "exceeds the water coming in, the water levels will drop indefinitely."

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Besides providing fresh drinking water, the Great Lakes provide energy through hydroelectric power.

The Robert Moses Niagara Hydroelectric Power Station and the Lewiston Pump Generating Plant are New York State’s two largest hydroelectric power plants, according to the New York Power Authority. Both are near Niagara Falls, which is formed by the Niagara River; the Niagara River carries water from Lake Erie into Lake Ontario.

"The hydroelectric power plant at Niagara Falls was one of the first in the country, and it's still a pretty large contributor to New York's power supply," Atkinson said.

The Great Lakes Water Quality Agreement, signed April 15, 1972, involved pledges by Canada and the United States to protect the Great Lakes. 

The agreement sets limits on phosphorus levels flowing into the lakes. Too much phosphorus would make the lakes subject to too much growth by algae and other invasive plants, Atkinson said.

"It's very important to conserve the Great Lakes," Atkinson said. The lakes, he said, "are essential to our existence."

Burke said the Great Lakes account for "over 20% of the world’s freshwater and over 80% of North America’s freshwater."

The U.S. Environmental Protection Agency says the Great Lakes account for 21% of the world’s freshwater and 84% of North America's surface fresh water. That’s in line with what Burke said.

We rate the statement True.