The idea is as old and dusty as the desert Southwest: Pipe abundant Great Lakes water to parched cities out West, such as Phoenix and Las Vegas. The idea's been dismissed for as long as it's been pitched, with adamant opposition from Great Lakes states, whose representatives crafted a pact with Canada just to stop such a thing.

But the latest person to see large-scale Great Lakes water diversions as a future likelihood might make some in the Midwest do a double take — the chief water scientist at NASA's Jet Propulsion Laboratory in California.

Jay Famiglietti, a hydrologist and senior water scientist at JPL, raised the possibility in an April 4 interview with ideastream.org, a nonprofit owner and operator of Cleveland public broadcasting stations. Famiglietti was in Ohio to speak as part of a lecture series at Case Western Reserve University.

Because of the Great Lakes' abundance of potable, fresh water, "you might imagine that there's a giant bull's-eye that can be seen from space that's sitting above the Great Lakes — meaning it's a target area, in a sense, for the rest of the country," Famiglietti said.

"Because there's so much fresh water, you can imagine that 50 years from now ... there might actually be a pipeline that brings water from the Great Lakes to Phoenix. I think that that's part of our future."

Those are fighting words around the Great Lakes.

"I don't think people in this region believe that is part of our future," said Liz Kirkwood, executive director of the nonprofit For Love of Water, or FLOW, which works to protect the Great Lakes.

But the global water crisis "is far worse than most people imagine," Famiglietti told ideastream, adding that in terms of both global water quality and water supply issues, "I'm sorry to say it's almost an unsolvable problem."

The Midwest relies upon the Great Lakes Compact, an agreement between the eight states surrounding the lakes and signed into law by President George W. Bush in 2008 as the primary safeguard of the lakes' water supply. The compact, among other things, seeks to prohibit any large-scale diversion of water outside the Great Lakes basin. A similar, bi-national agreement also involves the Canadian provinces on the Great Lakes — Ontario and Quebec.

But as need for fresh water potentially expands into even more of a crisis in the Western U.S. later this century, laws and policies protecting the Great Lakes could be attacked, overturned in a "national intervention," Famiglietti said.

"And I think that for these reasons, that we do have water in some places — the northern half of the country has a lot more water than the southern half — and so as the population grows, and as climate continues to change, we probably will have to move water from where it is to where it is not, and that will require some rethinking of some of these policies and laws," he said.

Free Press attempts to reach Famiglietti for further comment were unsuccessful Monday.

Nicholas Schroeck, an assistant professor and director of the Transnational Environmental Law Clinic at Wayne State University, remains skeptical that such a large-scale diversion will ever happen.

"I suppose you could come up with a scenario — let's say you had a president that, claiming the national interest, asked that a court, the Supreme Court, overturn the compact," he said. "It's a stretch. It's not transferring power from Congress or from one party to another; it's protecting a natural resource. It's a pretty unassailable document."

Another factor to consider: the costs of building and operating a pipeline system would be astronomical.

"The amount of energy it takes to move water vast distances is really expensive," Schroeck said. "If you're talking about a pipeline from Duluth, Minn., to Arizona, just imagine getting the water over the Continental Divide, the amount of energy it would take to move that water. It kind of boggles the mind. And it's an ongoing expense; it's not a one-time charge."

The likely tens of billions of dollars such a project would need might start making the Southwest's far larger, far closer water supply — the Pacific Ocean — a more logistically feasible and affordable option through use of large-scale desalinization, Kirkwood said.

Other, perhaps more logical solutions wouldn't require thousands of miles of pipes, Schroeck said.

"The thing that's crazy about all of these proposals is, we still have so far to go on conservation and water efficiency," he said. "If people are literally facing this kind of crisis, there are so many things they can do before considering a hundreds of billions of dollars infrastructure project.

"Perhaps it's not the wisest development to continue to expand and sprawl into arid locations without water."

As far-fetched as the diversion scenario might be, it's not impossible. When the U.S. sought a shipping channel between the Atlantic and Pacific oceans in the early 1900s, it split a country, Panama, in half with a canal. There's also an American flag and a dune buggy or two up on the moon that testify to the nation's ability to accomplish the costly and far-fetched when it decides it really wants to. Therein lies the lingering fear for those who think a large-scale water diversion from the Great Lakes would be disastrous.

"When we hear news about a NASA scientist even pondering the issue of whether the Great Lakes are for sale, it really heightens importance of us here to resolve the remaining, critical issues that the Great Lakes Compact has not yet resolved," Kirkwood said.

The fact that it's not a crisis that will happen overnight leaves time and opportunity to find different, better solutions, Schroeck said.

"The hope would be that before you need to do such a thing, we manage our resources better across the country, so this type of drastic action doesn't have to happen," he said.