Twenty-five years ago this very day, Louisiana citizens voted by an overwhelming 73-27 percent majority to create a constitutionally protected trust fund for wetlands preservation and restoration. That trust fund has achieved some notable successes but not nearly enough. Much more must be done to save this treasured resource and cradle of life.

One of the co-authors of this piece is conservative, the other liberal. We disagree on many things, and we have argued — in this newspaper — about the Southeast Louisiana Flood Protection Authority-East’s lawsuit against 97 oil, gas and pipeline companies. Yet regarding Louisiana’s coast, we agree on a lot more, including the fact that the energy industry caused significant damage to it. And we agree on the need for aggressive actions to combat these losses.

One such action, very much against the predilections of the tax-cutting Reagan-conservative co-columnist here, is enacting the decades-old idea for a fee to finance wetlands-related projects. Regardless of who is legally liable for damage to our coast, it is long past time to impose, going forward, a limited, fair and reasonable Coastal Wetlands Environmental Levy — as first proposed in the 1980s by Republican then-Gov. David Treen — on natural gas and oil processed in Louisiana and transported through pipelines and canals that, by their very nature, threaten marshlands.

Louisiana’s culture — its very soul — has been shaped largely by its coast, a coast not only of a haunting beauty but of enormous economic bounty. Yet right now, the whole coast — its beauty, the billions of dollars of productivity from shipping, fishing and energy production, the large human population that lives there — is at risk. Whether it all becomes a ghostlike memory, or survives, is up to us.

“Survival” is the right word. The disappearance of the coast jeopardizes lives. Without the wetlands acting as a buffer, not even the new levee system protecting metro New Orleans will protect against storm surges from future Katrinas or Camilles, and the rest of the coast lacks even what New Orleans has.

Let’s back up. What has, and hasn’t, been accomplished in the 25 years since then-state Sen. Ben Bagert pushed the trust fund through the Legislature and then sold it to the public in the 1989 referendum campaign? What is still at risk, and what remains to do?

First, let’s understand the trust fund’s evolving role. Originally, it secured a small portion of revenue from energy leases and dedicated it to coastal protection/restoration. From the very start, Bagert and his allies envisioned it as a lure for federal matching funds for that same purpose. Indeed, largely because the trust fund was created, Congress a year later passed what was known as the “Breaux Act,” providing a revenue stream for coastal projects.

Since then, the trust fund’s existence at least twice more has provided assurance to Congress that further financial commitments for Louisiana’s wetlands would not be diverted to other uses. Knowing funds would be guaranteed to go to the coast helped convince Congress to pass the Coastal Impact Assistance program in 2005 and the 2006 Gulf of Mexico Energy Security Act, which finally gives coastal states a share of revenues from offshore drilling in federal waters.

The trust fund has ensured that the state has some money to combat coastal erosion, but it is a tiny fraction of the need. Let’s look at the raw numbers, courtesy of the U.S. Geological Survey. From 1956 through 1988, Louisiana lost 833 square miles of wetlands, while gaining just 23 square miles through natural processes, for a net loss of 810. Since 1988 — the year before the trust fund was created — the state lost 677 square miles but gained a much more impressive 65 (a significant portion through state or federal projects), for a net loss of 612. Per year, then, the average net loss has slowed only from 25.3 square miles to 23.

So the restoration projects have proved effective, but their scale has been far less than what will be needed. The state has lost approximately 1,900 square miles since about 1930, and — here’s the scary number — another 1,750 square miles remain at risk.

Future land loss can be minimized and a sustainable future for the coast attained. That’s where the Master Plan comes in. Adopted by the Coastal Protection and Restoration Authority, an umbrella agency created under former Gov. Kathleen Blanco and strengthened under Gov. Bobby Jindal, the plan — passed unanimously by the Legislature in 2007 and 2012 and updated every five years — lists and prioritizes projects of all sorts, including river diversion projects, dredging and sediment pipelines, oyster reefs, marsh ridge creation and barrier island restoration, along with flood protection projects, and identifies the cost and other hurdles for each. It envisions the possibility of slowing wetlands loss for the next 30 years and then actually achieving net land gains after that, at a 50-year price tag of about $50 billion. (As a Tulane study notes, inflation will likely push that price tag closer to $95 billion.)

Those long involved with coastal wetlands policy know, however, that the politics of these projects can be far more complicated than the engineering. Where will the diversions (or other projects) occur? Who will be left outside a protection system? Who will pay for it? Current and expected revenue sources will provide some of the $50 billion, certainly enough to get started but nowhere near the entirety of it (much less the $95 billion, inflation-adjusted). CPRA director Jerome Zeringue says, “These projects build on each other, and it all depends on the money for our ability to implement them.”

That’s why we need the Coastal Wetlands Environmental Levy: to provide sustainable, reliable funding for Master Plan projects. The size of the levy could be negotiable and certainly small enough as to not deter energy companies from doing business and providing jobs in Louisiana. When Treen proposed it in 1982, it would have assessed 6 cents per 1,000 cubic feet of natural gas and 36 cents per barrel of oil “for the use of facilities associated with the transportation” of the fuels through the wetlands.

As oil prices per barrel have more than tripled since then to more than $90 per barrel, surely the companies could afford a similar, meager levy today.

The Coastal Protection and Restoration Authority and the Breaux Act, both well anchored by the trust fund created 25 years ago today, have provided a tremendous template for the next 50 years of coastal restoration. A small fee on the oil companies could provide the rest of the funds needed to implement it — to save Louisiana’s very way of life.

Advocate columnist Quin Hillyer is a contributing editor for National Review. John M. Barry is an author and the former vice president of the Southeast Louisiana Flood Protection Authority-East.