One man’s ceiling is another man’s floor. In 1995, fisheries biologist Daniel Pauly coined a phrase that described the gradual shift we experience when we consider what is ‘normal’—he called it ‘shifting baseline syndrome.’ Through the lens of his work he explained that, “each generation of fisheries scientist accepts as baseline the stock situation that occurred at the beginning of their careers, and uses this to evaluate changes. When the next generation starts its career, the stocks have further declined, but it is the stocks at that time that serve as a new baseline. The result obviously is a gradual shift of the baseline, a gradual accommodation of the creeping disappearance of resource species.”
Among environmentalists, baselines are important reference points for measuring the health of ecosystems. It provides information against which to evaluate change. It’s ‘how things used to be.’ If we know the baseline for a degraded ecosystem, we can work to restore it. But if the baseline shifted before we really had a chance to chart it, then we can end up accepting a degraded state as normal—or even as an improvement.
But what we consider normal often isn’t normal. “Instead, it is a steadily and insidiously shifting baseline, no different than convincing ourselves that winters have always been this warm, or this snowy. Or convincing ourselves that there have always been this many deer in the forests of eastern North America. Or that current levels of energy consumption per capita in the developed world are normal. All of these are shifting baselines, where our data inadequacy, whether personal or scientific, provides dangerous cover for missing important longer-term changes in the world around us.”
In his latest book, Feral: Searching for Enchantment on the Frontiers of Rewilding, British author George Monbiot advocates that we can tackle the problem posed by shifting baselines through the discovery of ‘trophic cascades,’ which he calls “one of the most exciting discoveries in the past 50 years in any branch of science.” According to Monbiot, “we are gradually beginning to discover that a trophic cascade accounts for all sorts of ecosystems all around the world.” Trophic cascades are said to occur when a top tier predator (such as a wolf) impacts a particular ecosystem by suppressing the abundance of prey or otherwise influences the distribution or behavior of other species, including non-prey animals, other large predators and plant species. In other words, it’s about introducing an element of abnormality (or normality, depending on which reference point you take) in a system. The classic trophic cascade was in a national park where the wolf population had vanished in 1926 but reintroduced in 1995 and within 10 years these two small packs of wolves had transformed the ecosystem of an enormous area of land.
The exploration of shifting baselines and trophic cascades can be extrapolated into a myriad of contexts. Continually questioning ‘normal,’ and what qualifies it as such, means we can catch things as they begin to slide rather than cleaning up a mess once it all hits the ground.