Ecosystems are complex. I learned that in a very real way during two summers on Alaska’s Pribilof Islands in 1993 and 1994. Participating in a joint U.S/Russian research project, our goal was to collect as much oceanographic data as possible around tiny St. Paul Island. Imagine a treeless island with the lush green hills and gray skies of coastal Scotland, coupled with the sights (and smells) from almost countless numbers of seabirds and Northern fur seals. Add a scattering of whale bones and carcasses washed up on the beaches, and you have a picture of summer on St. Paul Island.

Seabirds and Northern fur seals had been in decline, and our task was to find out why. So we rappelled over steep cliffs and hid amongst rocky shores, snaring and netting puffins, kittiwakes, murres and chuchkis (least auklets) to collect data on their diets. We waited patiently for the notorious North Pacific storms to cease long enough to collect oceanographic data. And while we suspected overfishing was to blame for the observed declines, our data were pretty inconclusive, being but an infinitesimal slice of a much bigger pie.

Because ecosystems are complex, ecologists are always hoping to find a scientific panacea,  a single cause-effect relationship that is responsible for the majority of the changes observed. While this can greatly simplify the scientist’s job of explaining the changes, it usually results in an oversimplification of reality. This form of reductionism is part of our human desire to find a cure-all, a scapegoat. We want to be able to point one finger, not all 10.

In 1993-94, our scientific panacea for explaining North Pacific seabird decline was overfishing. In 2015, it’s climate. According to a recent AP article by Dan Joling, a poorly understood phenomena called the Pacific Decadal Oscillation (PDO), could be to blame. Cooler waters tend to correlate with more seabirds, warmer waters with less.

But what is even more speculative is the article’s futuristic claims that global warming will eventually supersede the PDO. While Joling writes that the PDO is something “we’re just learning about”, the article ensures the reader that global warming is “an established fact.” No mention is made of the PDO’s possible influence on global temperature cycles.

But what if it turns out that the PDO is a major influence on global temperature fluctuations? What if it’s the major influence? And what about overfishing? It turns out, since the 1990’s, the pelagic trawl fishery for walleye pollock, is down about 50%. And young pollock are a major food source of seabirds. Interestingly, Joling’s article mentions that seabird populations have been stable since 2000, which makes one wonder why he titled the article “seabird loss.” And he even mentions that North Pacific water temperatures have cooled in recent years, in spite of the “established fact” of global warming, and in spite of the fact that the USGS data referenced in his article only goes through 2012.

And what about whales?  If human-caused global warming is truly the established fact that Joling’s article claims, then it must be responsible for the whales’ incredible comeback story, too, right? Since before the 1970’s, when NP seabird counts first started, whales have steadily increased. When animals like humpback whales, which consume as much as 3,000 pounds of fish and plankton a day, have a significant population increase, and they use the same summer feeding grounds (and food) as North Pacific seabirds, they just might cause seabird numbers to decline a bit. Joling’s article makes no mention of this possibility.

If anything about global warming could be considered an established fact, it’s the fact that it is almost always connected to loss, worry, fear, and catastrophe. But whales numbers are up, and everybody thinks that’s good. That simple fact should remind us again that ecosystems are complex, and that we as a society need to be more careful and patient in our quest to establish facts about them.

 

Featured Image Courtesy of Michelle Meiklejohn/freedigitalphotos.net