Early Warming. Nancy Lord
also in lakes, wetlands, and the water table, and in its various forms of precipitation and storage, including in glacial ice—is absolutely key to the Kenai Peninsula landscape and everything that landscape supports. Despite the high water I witnessed in May, I knew that the western peninsula was drying, and I wanted to understand both what that might mean and how the people who decide what it might mean do their work. On a coolish July morning, I joined my neighbor Ed Berg for a day trip into the heart of the Kenai National Wildlife Refuge, where he works as the refuge ecologist. We were joined by Dick Reger, a retired geologist who volunteers with Berg just for the fun of it, for a trip to the middle of the five Finger Lakes. Or Middle Finger Lake.
“We definitely got the idea why it’s called that,” Reger laughed as we readied gear at his cabin. A few days earlier, the two men, both in their late sixties, had canoed the length of that longest of the Finger Lakes against the wind.
Now, Berg, wearing an orange field vest with multiple bulging pockets and with his ever-ready hand lens on a cord around his neck, waited patiently while Reger showed me how to look at aerial maps with a stereoscope and pick out their three-dimensional features. Reger put on his own orange vest—with the six pens and pencils lined up in their pocket compartment—and tossed his lunch into a backpack. And then we were off, bumping down Swanson River Road into the refuge, nearly two million acres of federal land characterized by mostly scrubby forest, lots and lots of small lakes and two really big ones full of red salmon, plenty of wetlands, and on the southeast side, the Harding Icefield and its glaciers. This northern part of the refuge, near the town of Sterling, had been entirely burned in a 1969 forest fire and was now largely covered by skinny birch trees.
Berg and Reger explained as we drove that this lowland had once been lake bottom; during the last ice age, ice sheets had formed dams and impounded freshwater. The lakes that pock the refuge today, including the Finger Lakes, are known as “kettle lakes,” created from the melt of giant ice blocks left by retreating glaciers and filled by precipitation and groundwater; streams do not flow in or out of them, thus making them very useful for studying effects of climate change. Over time, they’ve been good recorders of what Berg calls “available water”—that is, precipitation minus the water that’s lost to evapotranspiration (the combination of water transferred to the atmosphere by evaporation and from the leaves of plants). The record is long; although glaciers remain in nearby mountains, the land here has been free of ice for about eighteen thousand years.
Our goal was to again canoe the length of the lake, for further investigation of a key geological feature called an ice-shoved rampart. The mystery of that berm of earth, and others within the refuge, might, the men thought, be unlocked into an understanding of past climate—and thus be useful for imagining a future.
As soon as we were out of the truck and lathering on mosquito repellent, Berg and Reger were examining and debating, with tangible excitement, oddities in the bark of some birch trees. This supreme inquisitiveness is what I love about Berg, whom I’ve known for years—since the time he was a carpenter—and from whom I’ve twice taken a geology class at our local college. Before the carpenter period of his life, Berg had been both a geophysicist and doctor of philosophy, and when he tired of hammering, he became a botanist. Berg is also particularly skilled at making science understandable to the public. His study of the spruce bark beetle and its warm-weather success at devastating Kenai Peninsula forests has been oft-reported in the popular press, in which he tends to be very quotable.6 “Beetles take no prisoners,” he once told reporters during a tour of the refuge. “It’s a Mafia-style execution.”
The woods, as we slipped through, were full of carefully observed insects, seedlings, bird calls, and a spruce tree clawed by a bear.
At the edge of the lake, we maneuvered into the water the canoe they’d previously left there. Reger, lingering in the shallows, examined acorn-sized freshwater snails; on the earlier trip he’d collected some for his home aquarium, and now he told me of the snail’s Asian origins and its passage—likely by birds—across Bering Strait. Berg, examining a sedge, quizzed Reger about its species.
Reger said to me, “Ed and I appreciate the same sorts of things. We have different backgrounds. He shows me this, and I show him something else. Everyone else thinks I’m a crackpot.”
The two men paddled, and I rode like an Egyptian princess in the middle of the canoe. A slight breeze rippled the water, but there was no real wind. The lake, long and narrow but indeed “kettlelike,” lay within steep sides and a surround of higher, forested land.
We stopped on a small island, and the two men went into high gear, digging holes and mixing soil samples with spit in their hands, referring to a soil color chart. This was not the day’s project but a side stop to explore how long the island had been an island as opposed to lake bottom, which would say something about water levels and climate. The men engaged in a vigorous discussion about soil “platyness” and how sand is winnowed from silt and the age of the vegetation on top. The island, they could tell, was wave-flattened, and the sandy soil on top had to have been deposited by waves that had washed over the island, perhaps not that long ago. There was essentially no soil on the island—just that sand over the silt that had been lake bottom. The trees—some birch, a few short spruces, alders—were sparse, and the ground beneath them was mostly mossy, with a few wintergreen plants and dwarf dogwood and, in a moist spot near the shore, reddish sundews with their tentacles and seductively dewy tips.
After the 1969 fire that destroyed so much forest in the refuge, Berg said, he would have expected the water level in the area to rise, not fall; trees would be drinking less, so more water would stay in the lakes. But, in general, the refuge’s lakes and wetlands were drying in the warmer temperatures and greater evapotranspiration associated with human-induced climate change.
In the expected cycles of warming and cooling, this part of Alaska should have been cooling. “Glaciers should be advancing,” Berg said, as he paused to wipe his brow with a bandana. “Climate change may be overriding the natural order of things.”
Then it was back into the canoe and only a short paddle to the south end of the lake, where we clambered out and approached a small berm with a hole dug into it and a pile of sandy soil to one side. This was it—our ice-shoved rampart, among the carpet of dwarf dogwood flowers and the dead leaves of the last year.
The men went back to work with a shovel, enlarging the hole they’d begun two days before on the landward side of the berm and from which they’d taken away a bit of woody evidence. Berg dug, and Reger squeezed and tasted soil samples, and then Reger dug and Berg talked to me about what they were doing. He spoke in his slow and always precise manner, in sentences that unfolded complete and orderly thoughts.
“What we’re doing here at Middle Finger Lake is excavating a berm that’s about two feet high, parallel to the shore, and it’s back thirty or forty feet from the shore. The base of the berm is about eight and a half feet above the present surface of the lake. These berms are formed by the ice bulldozing the lake sediments. This happens in the spring when the lake ice is breaking up and getting blown around by the wind. We find them on the south and southwest sides. The remarkable thing about these is that they’re so far above the present lake level—on other lakes we’ve found them twenty or twenty-five feet above the modern shorelines. Sometime in the past, the lake levels were very high—much higher than in the historic period. So we’re excavating this berm—or ice-shoved rampart—in hope of finding some pieces of wood we can date with radiocarbon. That will give us an idea about when these berms were formed.”
That—knowing when the lake levels were so high, the ice thick, and the northeast winds strong—could be matched to other climate data from that time period to tie regional effects to global ones and suggest linkages among conditions. An ability to “backcast,” as Sue Mauger was doing with stream temperatures on a shorter time scale, could help with forecasting a climate future.
On their previous outing, Berg and Reger had collected two small pieces of wood that, from their placement between bulldozed lake material and forest floor, appeared to have been at the bottom of two different rampart-building “shoving events.” Today, the goal was to get to a layer of soil underlying the whole berm. If they could