Shifting Baselines: Putting the World’s Oceans in Perspective

At day’s end, groups of divers gathered on the back deck to watch the sunset and share the adventures of the day. On one...

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At day’s end, groups of divers gathered on the back deck to watch the sunset and share the adventures of the day. On one side of the boat a collection of recently certified divers sounded like kids in a candy store. These divers were head over heels about their experiences. As soon as someone mentioned a scene or a creature that he or she witnessed, someone else raved about two more. They marveled at everything from the sighting of a moray eel, lobster and pair of angelfish to the colors of the sea fans. Tomorrow could not get here fast enough for this gang so they could see it all again.

Simultaneously, a group of experienced divers gathered on the other side of the same back deck. They had made the same dives alongside the new divers, but their reactions to what they saw were different. Instead of celebrating the day, their somber comments were made in subdued tones. Where, they wondered, were the big schools of jacks, the big groupers, the schools of snapper, the undamaged coral heads? Why did the reef seem so much less colorful and less alive than it had when they first explored the area a decade ago? Seeing only one lobster and one eel was difficult to believe. They did not want to rain on anyone else’s parade, but most of the old salts were quite saddened by what they perceived to be an ecosystem in decline.

But a couple of the longtime divers didn’t seem to notice or be bothered by the decline their peers claimed to see. Things seemed OK to them, and they felt their peers were seeing the glass as half empty instead of half full.

In a microcosm, the three interpretations of the same diving experiences illustrate the concept known as “shifting baselines.” While you might not have heard the term, in recent years shifting baselines has become a buzzword of major concern for many of the world’s leading ecologists, environmental biologists, environmental organizations, and everyone who is concerned about the health of ecosystems around the world.

The Buzz About Baselines

First coined in 1995 by Daniel Pauly, a fisheries biologist, the term shifting baselines describes the chronic, slowly degrading changes in various ecosystems that are difficult to notice because they occur subtly over time. This “decline over time” is in direct contrast to the sudden, dramatic and far easier-to-recognize type of environmental change seen in the recent Hollywood hit, “The Day After Tomorrow,” in which the rapid melting of polar ice caps leads to sudden, catastrophic environmental changes around the world.

In a marine ecosystem, the subtle changes might be the disappearance of one or two species one year, and one or two more the next, and again the year after that and the year after that. Or the decline might be schools of fishes in the same location that have all become slightly smaller.

It is easy to see how if the changes are subtle and occur over time that reasonable people might not notice. It is also plausible that an intelligent person could think that on a given day, or a given dive trip, that things were different because there are cycles in nature and you cannot reasonably expect to see the same type, number and size of animals on every dive trip. Perhaps, on a subsequent trip to the same reef, the same observer might see one or two specimens of an animal that they thought had disappeared, or they might see one really large specimen, and as a result, there might logically seem to be a regained sense of normalcy according to the memories of previous years.

The important point here is that if in fact there has been some general decline in a reef ecosystem, but the general population accepts the new state of the ecosystem as being as healthy and robust, then the baseline will have shifted. Instead of raising the cry of alarm and taking action, society will have accepted the less healthy state of the ecosystem as being perfectly acceptable, as being the norm, or baseline.

Another analogy that might help you grasp the concept of shifting baselines is the aging process in humans. Years ago my ideal weight was 165 pounds. Today, I’ll try to convince you that my ideal weight is closer to 180 pounds. Close friends who’ve known me for years will tell you that both my baseline and waistline have shifted.

While the example in my personal life might sound humorous, the shifting baselines in marine ecosystems are anything but.

Among environmental biologists, a baseline is a critically important reference point for establishing the health of an ecosystem, and for measuring any changes to or within the ecosystem. A perfect baseline will tell us what an ecosystem was like in its original state when it was pristine.

It Matters Where the Line Gets Drawn

It is also important to realize that the goal of many environmentally concerned organizations is to restore our oceans to their pristine state. They view the pristine state as the baseline. Keeping their eyes on this target is very important so that society doesn’t get too satisfied about its efforts when once severely threatened species begin to make a recovery instead of persevering to restore an ecosystem to its original state.

The case of salmon in the Columbia River in the Pacific Northwest illustrates the validity of this concern. Consider that the number of salmon that inhabit the Columbia River in the Pacific Northwest is twice what it was in the 1930s. That’s great news, if the data from the 1930s is the baseline. However, when making a judgment about the state of the current salmon population, it is also very important to realize that the number of salmon in the Columbia River in the 1930s was only about 10 percent of what it was in the 1800s. By 1930 the baseline had already shifted. If we want to restore the salmon population back to its original state, we need to look at least to the 1800s and even farther back if possible to establish target numbers.

The issues facing those of us who are environmentally concerned are not only what the oceans look like today but what they were like before the rapid expansion of human populations, advanced technologies and pollution of the last 100-200 years, and ultimately, what we want our oceans to look like in the future.

In theory it makes perfect sense to use the original pristine state of ecosystems as the baseline. However, establishing a perfect baseline requires that we know precisely what our kelp forests, coral reefs and other marine ecosystems were like many hundreds of years ago. But it is impossible to know with certainty. And if the baselines shifted before scientists could document them, as is the case in almost every scenario, then the odds for a modern society perceiving a degraded state as normal greatly increase.

In addition, there is a lot of pressure, much of which is economic, to accept shifted baselines. It seems that for the sake of growth in local communities and in corporate bottom lines that society is constantly being asked for ways to develop another part of a wetland, increase the amount of a given species that can be taken or lengthen a hunting or fishing season. Today, the rallying cry from many of the environmentally concerned is that instead of always asking the environment to give us a little more, society must give back and make concessions. This is true if the oceans are to be restored to their pristine state.

One of the major difficulties for anyone who is trying to help make others aware of society’s shifting baselines, the accompanying problems that result, and the general decline in the health of almost every ecosystem on Earth, is that their arguments almost always lack perfect data. In other words, the data to establish the baselines do not exist. No one counted the number of fishes on a reef or in a kelp forest thousands or even hundreds of years ago. As a result, it is very easy to refute both the latest data and any conclusions derived from new data by saying things like, “Show me the infallible proof that what we are seeing today is not part of the natural cycle. We all know that ecosystems are constantly in flux and that populations of various animals are not static, so how do we know that the data supports conclusions that indicate decline?”

To this point the discussion has been somewhat theoretical, but let’s look at an example of how the concept of shifting baselines affects the lives of real people and the future of the oceans.

The Case of California’s Proposed Marine Life Protection Act

Scientists tell us that overfishing, pollution, coastal development and other forms of exploitation are the major causes of the degrading health of the world’s oceans. They also tell us that California waters are no exception.

Studies indicate that game fish stocks are down in California, and that populations of various species are drastically out of balance with one another. The natural order of marine ecosystems is being greatly altered over time by human intrusion, with a large percentage of the change occurring in recent years. There is little if any argument from hordes of longtime California divers. Where, we ask, are all the big schools of fish, the abalone, the moray eels and big lobster? To many experienced divers the decline is obvious, but those Californians who do not snorkel or scuba dive have no concept of a healthy marine ecosystem, then or now.

In an effort to re-establish the health and viability of California waters for roughly the past seven years, the state legislature has been considering the establishment of huge marine reserves in which all forms of game collecting would be banned. This includes both sport and commercial fishing. Without getting too far into the specifics, it is fair to say that large, currently popular areas along the California coast and at Southern California’s majestic Channel Islands are included in the various versions of the proposed no-take zones.

The measure is extremely controversial, with sport and commercial fishermen leading the outcry against the establishment of the no-take zones. They claim, in essence, a constitutional right to fish because despite all of the scientific evidence that indicates serious degradation, it cannot be proved beyond a shadow of a doubt that marine ecosystems in California waters are in a general state of decline. In other words, there is no baseline of data.

While scientists assure us that one important way to preserve biodiversity in the seas is to create networks of no-take marine reserves where pollution is minimized, they also admit that they lack the original baseline data to make a perfect argument for demanding the establishment of no-take zones. Without the baseline data, fishermen claim it is not only unfair, but also unfounded in science, to ask them to give up fishing. Where, they ask, is the proof that stopping fishing will help solve the supposed problem.

Are the Oceans In Decline?

In 1969, a document known as the Stratton Report provided a comprehensive overview of the ocean policies of the United States. This was at a time when many considered the oceans to be an inexhaustible resource. The Stratton report was also the last and only report until quite recently when the Pew Oceans Commission and the United States Commission on Ocean Policy reports were conducted. In a nutshell, the conclusion from these comprehensive studies conducted by leading scientific task forces is that the world’s oceans are most definitely in serious decline, and that America’s waters are no exception.

The evidence for this conclusion surrounds us. Here are some excerpts, a mere sampling from the tip of this environmental iceberg, from recent studies that point toward the declining health of the world’s oceans:

  • Many scientists warn that due to the combined effect of global warming, pollution and overfishing, more than 50 percent of the coral reefs that exist today will disappear within the next 100 years.
  • World fish stocks are being diminished, and it is estimated that the stocks of the oceans’ biggest fish species have been reduced by 90 percent.
  • Climate changes in the next century are projected to greatly affect coastal and marine ecosystems as sea levels rise and the oceans flood highly productive coastal wetlands, estuaries and mangrove forests. Higher water temperatures will subject coral reefs to bleaching and lead to the demise of existing kelp forests. In addition, changes in climate and atmospheric circulation could adversely affect coastal upwelling, the flow of ocean currents and productivity of the seas, thus redistributing the abundance of marine resources.
  • Commercial marine fisheries in the United States discard as unusable as much as 20 billion pounds (9 billion kg) of nontargeted species every year. Astonishingly, this is twice as much as the desired catch of sport and commercial species combined.
  • Thirty percent of fish stocks that are being commercially fished in American waters are fished so hard that the populations cannot be sustained. As a result, natural food webs that have existed for thousands of years are being altered at alarming rates.
  • Every year in the United States more than 20,000 acres of wetlands and estuaries disappear due to coastal development.
  • Every eight months about 11 million gallons of oil from America’s streets and driveways run into the sea. That is the equivalent of the disastrous Exxon Valdez oil spill in Alaska in 1989. Oil spills actually account for only 5 percent of the oil entering the oceans. The Coast Guard estimates that each year sewage treatment plants discharge twice as much oil into U.S. waters as tankers spill.
  • Every summer, pollution creates a dead zone the size of the state of Massachusetts in the Gulf of Mexico, and 60 percent of America’s coastal rivers and bays are moderately to seriously degraded by nutrient runoff. This runoff leads to algal blooms and the degradation of coral reefs, kelp forests, seagrass beds and other coastal habitats.
  • In the United States almost 50 percent of the construction in the 1970s and 1980s occurred in coastal areas, and it is estimated that within 30 years a billion more people will live along the world’s coasts than do so today.


Common sense, supported by scientific leaders whose data is admittedly imperfect and incomplete, tells us that our oceans are in decline. The good news is that many of the causes, ranging from lack of governmental oversight to overfishing to pollution, have been identified. The question that each of us must ask ourselves is whether we are willing to turn a blind eye and accept the shifting baselines or fight to restore the health of the oceans so many of us dearly love, even when it means that we might have to make compromises in our own lives.

The Way Shifting Baselines Get Accepted

The following hypothetical example about the beaches of the fictional community of Seaside City illustrates how baselines get shifted. While the example is hypothetical, the lessons can be applied to hundreds of beach communities in the United States and around the world.

It is no secret that today in the magical land of Seaside City the ocean water off many public beaches gets so polluted at times that concerned officials close the beaches for reasons of public safety. But that has not always been the case. Before humans first appeared in Seaside City, these waters were almost never polluted by natural causes. As humans began to settle into Seaside City 150 years ago, some pollution-related problems began to appear, but these problems were rare and almost all of the beaches were pollution-free more than 90 percent of the time. As time passed, more and more people moved to Seaside City and there was continued growth and development. More and more pollution-related problems occurred. But the proponents of growth and ocean exploitation proudly looked at their growing community and told everyone not to worry about the health of the oceans. After all, 80 percent of the time the beaches are pollution-free.

More time passed, and with continued human effect, pollution increased and there was more pressure exerted on wildlife. But the political leaders of the next generation desired more growth, and told the people of Seaside City to support it for the sake of their economy. They assured residents that there was no need to be concerned about the myth of declining oceans. After all, 60 percent of the time the beaches were pollution-free.

It’s easy to see that if subsequent generations continued the trend that before long a so-called community visionary might be telling people not to worry about the health of the beaches. After all, on 5 percent of the days Seaside City has the world’s most beautiful, pollution-free waters.

For more information and to order a free Shifting Baselines Action kit, visit

By Marty Snyderman