Treating Arctic Ecosystems as Systems
Why should we be concerned about shipping in Arctic waters? What would be the consequences of commercial fishing in the Arctic Ocean? How do we anticipate the effects of climate change in the far north?
If we are to conserve and sustain Arctic ecosystems, we need to approach questions of this kind in terms of systems. An ecosystem has no leader to orchestrate the actions of its many constituent parts. Instead, the way it functions arises solely from the interactions of its component species (humans included), habitats, and physical features as they affect one another, directly and indirectly. The complexity that emerges from these many modes of interaction may frustrate clear understanding, including the ability to predict the outcomes of human actions, but we must address it nonetheless. In large part, this means recognizing the limits of our knowledge and acting with caution and care.
We learn a great deal if we pay attention to each part of a system separately, breaking complexity down into manageable pieces that can be studied with attention and precision. We also miss a great deal. It is not enough to know the nutritional needs and growth rate of the average ringed seal. We need to know about its prey (such as Arctic cod), where its habitat can be found, and crucially, how the seals and all that surrounds them react to change. Thinking about such relationships is the basis for ecology and ecosystem approaches to management.
Putting theory into practice, however, is difficult. Many observational and laboratory studies have looked at the way that changing one parameter can affect other parts of the system. For example, how does water temperature influence the survival rate of juvenile Arctic cod? This is an important question, because Arctic summer water temperatures are rising, creating opportunities for the Arctic cod’s competitors, such as saffron cod. The saffron cod is not as energy-rich as the Arctic cod, so a larger population of the former at the expense of the latter could leave a lot of hungry ringed seals.
But the essence of complexity is that things are never simple. Complexity is not the same as being complicated. A complicated system may have many moving parts, as in an elaborate clock, but the results are easily predictable, with dials and hands moving at a reliable pace in a regular direction. In a complex system, on the other hand, actions reverberate through many of the component parts, affecting the piece with which the action started, and thus leading to another cascade of effects. This is the famous “butterfly effect,” in which the flapping of an insect’s wings in one location may eventually have an impact on weather patterns a great distance away.
If animals are involved, complexity includes not just the physical effects that transform air movements into thunderstorms, but also the ability of the animals to adjust and adapt as conditions change. When sea ice disappears, some polar bears may have to forgo their usual diet of ringed seals and instead spend the summer on land—eating eggs, plants, and whatever else they can find.
Individuals and species will die out when change is too great, but change need not always be detrimental. Polar bears in the Chukchi Sea off northwestern Alaska appear fat and happy, contrary to what might be expected from the rapid loss of the region’s summer sea ice—so what might appear to be a simple story of temperature, prey, and predators has taken a twist. If we wish to understand why polar bears are thriving for now in the Chukchi, and how human actions might affect the bears and all that supports them, we must consider the ecosystem in which the Arctic cod, ringed seal, and polar bear live.
This ecosystem is not a static set of functions and processes and components that can produce only the species we know today. Instead, it is always altering in one way or another. It may be tempting at this point to throw up our hands in despair at the prospect of ever understanding a complex system well enough to make predictions about it. Such caution is sensible, as there are many examples in which predicted doom never came or promised abundance was met with disaster.
But systems are not irreducibly and hopelessly complex. If they were, humans would never have been able to discover the patterns and indicators that have allowed us to thrive in nearly every climate and landscape we find. For example, taking advantage of an annual salmon run seems a simple task, but sustaining a community and a culture over generations requires understanding more than where to catch a fish. The peoples of the Northwest coast of North America have done what they can to protect and enhance salmon stream habitat, which is the portion of the life cycle they can affect, while trusting the ocean to provide what the salmon need while at sea. The fishers also have paid attention to the strength of the salmon runs, to make sure that enough survived even in lean years to produce the next generation of fish.
These ideas, embodying care and caution, continue to be relevant if not essential in a world experiencing climate change, pollution, landscape transformation, industrial-scale catches of marine creatures, and ever-increasing demands upon our planet. When human activities and actions threaten to disrupt an ecosystem or any of its components, we have an obligation to consider carefully the consequences of our decisions—and to not claim surprise when something unexpected occurs. Complexity requires us to embrace the uncertainty we will inevitably encounter and to acknowledge that many things lie beyond our control.
While we need not treat every ecosystem as delicately fragile, neither can we expect every ecosystem to be resilient in the face of whatever we throw at it. Ecosystems cannot anticipate or plan, so we must be attentive to our interactions with the ecosystems that sustain us. Unfortunately, we have all too much evidence to show what happens when we treat ecosystems as simple, reliable mechanisms that magically provide us with air, water, and food no matter what we do to them. Being aware of the nature of complex systems offers us an alternative, as we consider questions such as those with which this essay began. We need to give the environment our continued attention, recognizing complexity so that we can do our best to avoid problems and can adjust our actions when things go awry.
Henry P. Huntington is a senior officer for The Pew Charitable Trusts, where he directs the science work of its Arctic programs.
This piece was originally published in Environment: Science and Policy for Sustainable Development.