Book Review: Narwhals
/Narwhals: Arctic Whales in a Melting World
Albedo is simply a fancy word for reflectivity of surface. White snow has a high albedo - 80 percent of the sunlight that strikes snow is reflected back up into space. If the planet begins to warm up and some of that snow and ice begin to melt, it exposes darker underlying surfaces of ocean water or tundra, which have a lower albedo and absorb more solar radiation. That warms the system even more and melts more snow and ice, creating a domino effect of increased melting that cannot be stopped. Because the albedo feedback is mostly taking place in the polar regions, it's the Arctic and Antarctic that are being affected most by global warming. As warming occurs over the Arctic Ocean, that warmth spreads over land, hastening the decay of the permafrost in the tundra, triggering tiny organisms in the soil to become more active and begin releasing some of the 1,600 gigatons of carbon stored there (compared to the 730 gigatons in the atmosphere), further aggravating the situation.
Lodged right in the middle of that death-knell passage is its key phrase, "that cannot be stopped," and that phrase means radical change for the Earth's frozen poles. Over millennia (since the last time they melted), those poles have become otherworldly in their environmental extremes, scourged by winds, plunged into darkness for months at a time, and wasted with a kind of deep cold that's hard to imagine if you've never experienced it. The High Arctic is among the most inhospitable places on the planet - and yet, like the rest of Earth, it teems with life. The green-black waters around Greenland and northern Canada are filled with cod, halibut, and squid, which are preyed upon by hardy void-explorers like the narwhal, which are in turn preyed upon by nightmarish killers: the polar bear and the killer whale (one of the researchers McLeish talks to casually refers to narwhals as "orca candy"). It's an ecosystem carefully balanced on the knife-edge of the land's exigencies, and the narwhal is among the most exquisitely adapted to it:
... narwhals live in a world few can even imagine, where darkness and icy conditions are insurmountable barriers to all but a few predators, some of which may venture north during the warmest months to partake of the region's food-rich waters but then quickly depart for warmer climes at the onset of fall like so many human snowbirds. Their food source is often found more than a mile deep, where few mammals can survive. It's the physiological adaptations to cold and deep diving - and to darkness, too, forcing them to rely much more on their hearing and acoustics than on sight - that put the narwhal on the top of my list of most revered animals.
In a series of genial, fast-paced chapters that read like the best New Yorker science reporting, McLeish covers the history, natural history, and fantasy-life of this storied creature which possesses "the most remarkable tooth in nature" - the long corkscrewed tusk protruding from the front of the narwhal's head. For centuries, that tusk has played an oddly energetic role in human folklore; it's been prized for its rarity (Queen Elizabeth I had one that was valued at the price of a modest castle), ground down for its curative properties, and used as the central prop in the vast mythology of the unicorn. It's also been the object of countless trophy-takers, and this, plus the high quality of the narwhal's body fat and oils, has kept it continually hunted by humans.Adapted to live in the punishing conditions of the High Arctic, the narwhal is a survivor (at one point in the book, researchers encounter a female with polar bear claw-rakings down both sides of her body - the bears leap onto the whales from the pack-ice and then hold on for dear life until they've made the kill; who knows how many have been drowned in the below-freezing depths when the whales dive to save themselves), and the most pressing question of McLeish's excellent, optimistic book is whether or not they can survive the disappearance of the High Arctic itself. Like any sensible person, McLeish has made special trips to see the narwhal skeleton - complete with seven-foot horn - mounted at the Harvard Museum of Natural History. It's an arresting sight, but McLeish isn't alone in hoping it's not a harbinger of a hotter, emptier world.
