Rising. Elizabeth Rush
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changing as a result of human activity. In our era of unprecedented geologic transformation, the very act of scientific observation has taken on an added sense of urgency. In the coming years, portions of, if not all, places like Jacob’s Point and the Sprague are likely to be underwater. We will want to know why, but we need the data first. The chance won’t come again.
In recent years scientists have discovered that coastal wetlands—salt marshes, but also mangroves and saw grass meadows—store a quarter of the carbon found in the earth’s soil, despite covering only 5 percent of the planet’s land area. That means that an acre of healthy coastal wetlands will clean far more air than an acre of the Amazon. “They sequester about fifteen times more carbon than upland forests,” Beverly tells me. “But how effective are these ecosystems when they have been dammed, diked, culverted, or drained? That’s what we’d like to know.”
Dana unloads a large Plexiglas box and an eighty-thousand-dollar machine that looks like a waterproof stereo receiver from the back of the college van. “It’s a cavity ring-down mass spectrometer,” says Joanna Carey, a biogeochemist who, like the machine, is on loan from the Marine Biological Laboratory at Woods Hole, Massachusetts. “We use it to measure carbon dioxide, methane, and water vapor levels being ‘respired’ by the marsh so we can get a better idea of how higher sea levels will alter the net balance of greenhouse gases in these already-altered coastal ecosystems.” As the marsh is further destabilized, it is possible that the organic matter that was stored in and around the root systems will decompose, releasing back into the atmosphere the very gases—carbon dioxide and methane among them—the marshes once sequestered.
Dana places the contraption into a wheelbarrow. “Cailene and I nicknamed it the Science Box,” he says. It used to be that we thought the earth’s climate and its underlying geology changed slowly and steadily over time, like the tortoise who beat the hare. But now we know the opposite to be mostly true. The earth’s geophysical makeup doesn’t tend to incrementally evolve; it jerks back and forth between different equilibriums. Ice age, then greenhouse. Glaciers covering the island of Manhattan in a thousand-foot-thick sheet of ice, then a city of eight million people in that same spot. The transition between the two is often quick and relatively dramatic. Contraptions like the Science Box help us keep track of just how fundamentally things are changing, illuminating the ways in which human activity is pushing the planet beyond “greenhouse Earth” into some even warmer, preternatural state.
The Science Box takes various vapor emission readings at a rate of one per second. From these readings Dana will generate one “flux,” or an image of the overall rise or fall in the methane and carbon dioxide coming off one square meter of marsh. Then he will compare the fluxes gathered in healthy areas against those in places that have already begun to rot from within, creating a picture of the potential impact sea level rise will have on a tidal marsh’s ability to sequester greenhouse gases.
The amount of data the Science Box generates in four minutes would take a human 3,600 minutes to collect by hand. Which is exactly what Cailene spent her summer doing in Long Marsh, a “fingerling” tidal wetland about ten miles northwest of here as the crow flies. There is no road to the marsh’s terminus; to reach the transition zones where the readings are most telling, Cailene must drop down the side of a culvert near the marsh’s mouth. Then she hikes through the waist-high grasses, hopscotching across rivulets and drainage ditches until she reaches the end. It takes her thirty-three minutes to travel from stem to stern. She can’t safely cart the Science Box all the way back there, which is why she collects her readings the old-fashioned way—with a twenty-five-milliliter syringe and an Exetainer vial. Tapping away at the calculator app on her cell phone, she says that it took her months to produce one-tenth of the data the team will collect today.
Cailene and Dana will devote much of the upcoming academic year to better understanding what separates a healthy tidal marsh from one that is not, and the rate at which each releases greenhouse gases into the atmosphere. Or, as Beverly describes it, “They are filling in the equation that describes today’s carbon cycle.”
As I drove down State Route 209 and out on the fog-struck peninsula that morning, the local NPR radio personality likened the weather to pea soup. The midday heat was bound to break records, he warned. Now, listening to Cailene, I understand that it is going to be not only the hottest day of the summer but also one of the most important, at least for these young researchers. As we prepare to walk, Dana adjusts his straw cowboy hat and tugs at his sun-bleached Cisco Brewers T-shirt, pulling it over his belt. Then he looks out across the sea of saltwater cordgrass and black needlerush, places his hands on the wheelbarrow handles, and enters the humming midmorning light. Not only will today’s work net the raw material of his yearlong thesis project, it will hopefully help illuminate how drowning tidal marsh ecosystems could inadvertently contribute to the ongoing inundation of the coast.
For much of human history we have had very little sense of the dynamic nature of life on the planet. Three hundred years ago we didn’t know that the earth has been regularly covered in massive sheets of ice that pulse in and out from the poles like a scab forming and retreating. We didn’t know that the continents were in constant motion or that animals could go extinct. We didn’t know that light traveled faster than sound or that bacteria caused disease, and we didn’t know that the universe began not with God’s word but with a big bang.
Right up through the middle of the eighteenth century, Westerners thought the earth began roughly four thousand years before Christ. But unearthing evidence of species that modern humans knew absolutely nothing about—such as a massive mastodon molar found in present-day Kentucky—hinted that there had once existed many other worlds, which had flourished and vanished over a previously unimaginable length of time. One of the earliest books to acknowledge the idea that the earth’s history might be much longer than our own was Charles Lyell’s Principles of Geology, written just over a century and a half ago. It popularized the work of William Smith and James Hutton, who spent decades comparing the appearance and disappearance of different fossilized animals in the red sandstone cliffs in Devonshire, England, in the late 1800s. As John McPhee writes in Annals of the Former World, “Some creatures … had appeared suddenly, had evolved quickly, had become both abundant and geographically widespread, and then had died out, or died down, abruptly. Geologists canonized them as ‘index fossils’ and studied them in groups” in order to get a better sense of the age of our planet. The earth scientists at Devonshire painstakingly compared these “index fossils” against each other and in doing so started to divide geologic time into different epochs. Their studies suggested that, contrary to popular belief, the earth had likely been gyrating just outside the asteroid belt for the better part of four hundred million years.
Of course this estimate of the earth’s age was not accurate either. It wasn’t until radiometric dating was pioneered by Arthur Holmes at the turn of the last century that we improved on this rough calculation—by a huge margin—and discovered that our planet actually came into existence roughly 4.5 billion years ago. Though our tools have progressed, most nongeologists, me included, are still likely to wildly misidentify different events in geologic time, often by orders of magnitude.
Four thousand, four hundred million, or 4.5 billion years—it is all the same to us. We tend to think in human lifetimes, and even there our scope is limited. We are individually preoccupied by the lives of those we know and expect to know: our grandparents, parents, children, and, if we are lucky, grandchildren. Which is why it is so fantastically difficult for us to recognize that in our frenzied attempt to keep nearly eight billion people fed, watered, clothed, sheltered, and distracted, we are fundamentally altering the geophysical composition of the planet at a pace previously caused only by cataclysmic events, like the massive asteroid that smashed into eastern Mexico, wiping out the dinosaurs, sixty-five million years ago.
Lately, Earth-minded scientific researchers and activists alike have taken to condensing the history of the planet into a single calendar year to explain just how temporally insignificant human civilization is and how profoundly we have changed the planet in the time it takes, relatively speaking, for a rufous hummingbird to beat its wings. In this version of history,