Grand Isle, La.

It is pretty much a tossup for me: Who poses a greater long-term threat to America’s Gulf Coast ecosystem: the U.S. Senate or BP? Right now, from what I’ve seen flying over the Louisiana coast at the mouth of the Mississippi, my vote is the U.S. Senate. BP at least seems to have finally gotten its act together and is cleaning up the oil spill. The Senate, in failing to pass even the most modest bill to diminish our addiction to oil and begin to mitigate climate change, has not even begun to do its job.

I have to admit, I was surprised and pleased that it took us an hour of flying in our float plane over Breton Sound and Barataria Bay and across the marshes, bayous, barrier islands and open water that lie about 70 miles from the site of the Deepwater Horizon rig before we spotted any significant ribbon of oil. “There it is,” said our pilot, as he banked the plane for a better view of the small oil slick and as if he were pointing out a pod of whales we had been searching for all day.

Here’s the good news. Thanks to: the capping of the broken oil well; the cleanup efforts so far by a flotilla of shrimp boats converted to skimmers; the currents that have blessedly taken a lot of the spill away from the shore; the weathering process that is breaking down a lot of the crude into different compounds that dissolve, evaporate or get absorbed by microbes in the ocean; and the dispersants that have broken up the biggest oil slicks, there is less and less to see here on the surface. Walking along the beach on Grand Isle, the only inhabited barrier island on Louisiana’s Gulf Coast, it appears that our worst fears have not materialized — so far.

So much for the good news. The bad news is what you can’t see that is happening under the ocean’s surface and the stuff you can see — the decades of degradation along the whole Gulf Coast from decades of unfettered development — that no one is talking about.

“From a biological perspective, we know what happens when oil hits the beach. We can see those impacts; we can mitigate those impacts; we can quantify those impacts,” said Keith Ouchley, the biologist who leads the Nature Conservancy in Louisiana. “What we don’t know are the biological impacts that occur as that oil is dispersed through the deep water columns under the ocean’s surface. We don’t know what it is doing or affecting today or in the future. There is very little experience with this scale of spill at these depths in such a biologically productive system as this.”

The greatest concern, added Ouchley, is what impact the undersea oil concentrations could have on the billions of tiny larval fish, shrimp and other organisms that are at the bottom of the whole marine food chain — and we may not know that for many years.

What compounds that worry is that the marshes, sea grasses, oyster beds and barrier islands that provide the nurseries for those larval fish, shrimp and other marine life — and that provide natural barriers against storm surges from hurricanes — had already been dramatically weakened long before the BP spill. That was thanks to the building of levies that have prevented the rivers’ natural flooding of life-giving freshwater and sediments into the marshes, as well as the laying of oil and gas pipelines and shipping navigation channels all across the ecosystem. “A football field of marsh is being washed into the ocean every 30 minutes,” said Ouchley.

Bob Marshall, an environmental reporter for The Times-Picayune of New Orleans, put the BP spill in the right context when he wrote: “We need to remember this is a temporary problem on top of a permanent disaster. Long after BP’s oil is gone, we’ll still be fighting for survival against a much more serious enemy — our sinking, crumbling delta. Our coast is like a cancer patient who has come down with pneumonia. That’s serious, but curable. After the fever breaks, he’ll still have cancer.”

That’s where the Senate has failed miserably. There are three things it should be doing for the gulf and our other vital ecosystems. First, taking out some minimal insurance against climate change by reducing our carbon emissions; this region is particularly vulnerable to sea level rise and the more intense storms that climate change will bring. Second, set us on a path to diminish our addiction to oil so we don’t have to drill in ever-deeper waters. And, finally, provide the federal funding to restore America’s critical ecosystems. The Senate abandoned the first two but is still working on the third.

The Senate’s failure to act is a result of many factors, but one is that the climate-energy policy debate got disconnected from average people. We need less talk about “climate” and more about how conservation saves money, renewable energy creates jobs, restoring the gulf’s marshes sustains fishermen and preserving the rainforest helps poor people. Said Glenn Prickett, vice president at the Nature Conservancy: “We have to take climate change out of the atmosphere, bring it down to earth and show how it matters in people’s everyday lives.”