The Habitable Planet: A Systems Approach to Environmental Science
Looking Forward: Our Global Experiment Scientists
Content Developer Bio: Daniel P. Schrag
Daniel P. Schrag
Daniel Schrag is professor of Earth and planetary sciences and environmental engineering at Harvard University and the director of the Harvard University Center for the Environment. Schrag studies climate and climate change over the broadest range of Earth history. Schrag received a B.S. from Yale in 1988. He majored in political science and geology, beginning an interest in science and policy that continues to this day. As a graduate student at Berkeley, Schrag was introduced to geochemistry and paleoclimatology through his work developing new methods for reconstructing ancient climates. After receiving his Ph.D. in 1993, Schrag taught at Princeton until 1997, when he moved to Harvard’s Department of Earth and Planetary Sciences. In his research, Schrag applies a variety of techniques from analytical chemistry to a wide range of Earth materials including trees, corals, and deep sea sediments, using the data to understand the chemical and physical evolution of the atmosphere and ocean and the relationship to the evolution of life. He has studied the physical circulation of the modern ocean, focusing on El Niño and the tropical Pacific. He has worked on theories for Pleistocene ice-age cycles over the last few hundred thousand years. He helped develop the Snowball Earth hypothesis, proposing that a series of global glaciations occurred between 750 and 580 million years ago that may have contributed to the evolution of multicellular animals. He has also worked on the early climates of Earth and Mars nearly 4 billion years ago. He is currently working with economists and engineers on technological approaches to mitigating future climate change. Among various honors, Schrag was awarded a MacArthur Fellowship in 2000.
Featured Scientists Bio: Daniel Pauly
Daniel Pauly is professor and director of Fisheries Centre at the University of British Columbia (UBC) in Vancouver, Canada. Dr. Pauly’s scientific output, mainly dedicated to the management of fisheries, and to ecosystem modeling, comprises numerous contributions to peer-reviewed journals, authored and edited books, reports and popular articles, and the concepts, methods and software he (co-) developed are in use throughout the world. This applies notably to the ecosystem modeling approach incorporated in the Ecopath software (see www.ecopath.org ), to FishBase, the online encyclopedia of fishes (see www.fishbase.org), and the global mapping of fisheries trends (see www.seaaroundus.org). In 2003, he was named one of UBC’s Distinguished University Scholars and elected a Fellow of the Royal Society of Canada (Academy of Science). In 2004, he received the Roger Revelle Medal from IOC/UNESCO, and the Award of Excellence of the American Fisheries Society. In 2005, Dr. Pauly received the International Cosmos Prize, a prestigious award granted by the Expo’90 Foundation of Japan, for research excellence with a global perspective.
Featured Scientists Interview: Daniel Pauly
Interview with Daniel Pauly
Interviewer: Would you tell us about your research.
DANIEL: I’m the Director of the Fishery Center at the University of British Columbia in Vancouver, Canada. I’m a professor of fisheries and I work on a global scale. Very few people work in fisheries on a global scale; most of them are limited to a bay or fishery in the Gulf or a country at most, but not internationally. Before that I worked in the tropics.
Interviewer: So what got you first interested in science?
DANIEL: I grew up in Europe, specifically in Switzerland, and I studied in Germany. I wanted to study something that would be of use in a developing country setting because I planned to leave Europe and to work presumably in Africa. And I wanted to study a science, which would have practical implication, because at that time in the 60s everybody wanted to help out. And because I couldn’t do physics, I wanted to study biology.
Interviewer: And what got you interested in marine biology?
DANIEL: Really nothing special. I’m very different from a scientist like E.O. Wilson who had a deep affinity to the real organism. I can go through a forest and not see the birds. I’m interested in the ideas that represent the process—that linking co-system. I like the way explanations are found for things that happen in the ocean and things that happen in nature. I enjoy this, and I like to see the patterns. So I work not on the things themselves, I like to see patterns and data that represent processes.
Interviewer: Why is it important to study marine ecosystems on a global scale?
DANIEL: When I decided to work on global fish populations, global fisheries as a global phenomenon, I had been in the Philippines working on tropical fisheries, on single fisheries. I was surprised when I spoke with a colleague and learned that The International Rice Research Institute was working on developing a new variety of rice for planting. The rice people knew very well what the rest of the production in the world was. In other words, they could put their rice in the context of worldwide production. But I could not put the fisheries that I was studying in the context of world fisheries. And I realized that actually very few scientists were working on world fisheries as a topic. With a friend, I started writing a series of little papers on world fisheries and realized many assumptions that I had made about the world catch and the world potential. So I in a sense, created a field of world fisheries as a study object.
Interviewer: You were looking at an ecosystem in one area. What made you move to a more global outlook?
DANIEL: I really zoomed in on the concept that fisheries have sampling devices. For fifty years, fisheries data have been collected by the Food and Agriculture Organization (FAO) of the United Nations in Rome. People fish wherever they can and wherever there is fish for them to catch. And they don’t fish where there are no fish. So by studying what they catch, i.e., the catch data, the catch statistics, you can infer some things about the state of the ocean. I’ve become a specialist in the analysis of this FAO data. Up to the mid ‘90s, the data wasn’t analyzed by scientists; it was just taken as a gospel. I began to analyze the statistics in some detail. The first paper that I wrote was a re-computation of the amount of primary production that was needed to sustain the catch and the world catch, because up to now people were doing the inverse procedure. They were looking at how much primary production there was and then how much potential catch there would be. And this computation I always thought came with a huge amount of uncertainties. So I did the inverse, which is to look at a catch and to infer how much primary production was needed and what fraction it was of the primary production. I published this paper in Nature in 1995, documenting for the first time that we had a huge impact on the sea because at least in the shallow waters around the continent, we were thinking one-third of a primary production was needed to sustain the fisheries.
Interviewer: What are some specific things you’ve learned from your analysis of the FAO data?
DANIEL: We transformed the data into maps. The first result that we looked at was the fact that China was catching much too much. It was impossibly high. We looked at this in depth. And in 2001, we published a paper in Nature that China was over-reporting its catch, they doubled the catch that they legitimately needed to catch. The result of this was that the world fisheries were not increasing in the ‘90s, but decreasing. So we discovered that world fisheries had begun to decrease from the late ‘80s on.
Interviewer: And what did you learn about the Japanese industry?
DANIEL: Again, we used the catch data that the countries sent to FAO and that FAO processes. The second step we did was replace this data in various countries by the data obtained directly from their countries. In other words, in most countries you have the Department of Fisheries collecting data, writing reports. And the Department of Statistics or the Department of the Prime Minister’s Office or the Financial Minister sends the data to FAO in Rome. But there is a loss of information between the Department of Fisheries and the institution that sends the data- that loss of information can be compensated for by reacquiring the data that are available at the country level. You discover that for political reasons or for reasons of convenience that many, many countries don’t report what they catch. We have started a series of investigations on that. It turns out that, for example, the State of Hawaii underreports the catch of its inshore fisheries by a factor of two. But Guam and the Mariana Islands and other islands that are U.S. flag territories underreported by a factor of ten to fifteen. We have found that this is a pattern generally repeated throughout the Pacific, people don’t know that they catch a huge amount of fish in their inshore fisheries.
Interviewer: How far back does the catch data go back?
DANIEL: The catch data that FAO had collected, started in 1950, which was a good time to begin because World War II destroyed lots of fishing capacities in a lot of countries and the boats were used for other purposes. This provided a good baseline. Also, lots of the countries that are now developing were colonies of the European nations in the ‘50s. So the ‘60s and the ‘70s reflect the attempt to free themselves and build new fisheries.
We also know from studies conducted with historical sources, such as expeditions, that there is another reality that goes way back when stocks were completely untouched that my colleague, Jeremy Jackson, addresses. The analysis of this catch data enables a rigorous evaluation of the trend in fisheries. And we must use the old data, contrary to the fashion in most fisheries research, because we need a good baseline. We need to know how it was before it began to be strongly industrialized. This provides a contrast that we can use to see how fisheries are today. If we use only the last ten years, we would not see anything happening.
Interviewer: Can you tell us about the historical expeditions. What do they tell you?
DANIEL: In the sixteenth century, European countries began to systematically send expeditions throughout the world. These expeditions very much represent the equivalent to our sending the space shuttle nowadays. In addition to the captains, you’d put so-called naturalists on the boats. The most famous of them was Darwin. The naturalist was the doctor on board. But he was also the narrator of the expedition and the one who observed what was found and reported it. The expedition then sent back the loot they had acquired to Europe, to the museums, equivalent to bringing home solar dust or rocks from the moon. The scientists of the time, they all gathered to have this information available. Now we can now look back at these reports and we see descriptions of the various countries that are now developing countries. We can see the description, for example, of abundance, abundance of mammals, of birds, of life in general, which we can use and plot. We can plot against time; we can plot the range of certain animals and we can see them declining. Jeremy Jackson has worked on this and a colleague of mine, Maria Palomares, works on this extensively. She records the anecdotes, the observations of animals, and quantifies them where they reflect abundance or rarity. Over time, we see that for a certain group, say, seabirds, you would have their abundance observation diminish and the rarity observation increase. So you’d plot this over time; and so you have a time machine that enables you to quantify by diversity of observation for three hundred years in the past, which we couldn’t do before.
Interviewer: Industrial data, catch data, historical records – is this science?
DANIEL: This certainly is science. It is science to observe and to quantify. It doesn’t matter what the instrument is you use. Many people believe that biology was equivalent to physics where you can turn the direction of the change and it doesn’t matter which way it is analyzed. For example, how the planets turn around the sun. They could turn backward and it would be the same thing. In biology, it matters a lot. Our role of time is only in one direction. For example, it’s extremely hard to recover ecosystems once they have broken. And it’s also extremely hard to recover broken abundances of certain animals. In fact, when a species is gone, you cannot rebuild it.
The processes that generate the observations are different. But you’re trying to infer from processes that are not amenable to the senses directly, you’re trying to infer what happened from points on a graph. And it doesn’t matter whether that is generated by a nuclear reactor, by an accelerator or three hundred years of history.
Interviewer: When you put together all this data, what are the results are?
DANIEL: When you put together the open expeditions plus bridging data that we have in certain countries from 1900 to World War II and the field data from 1950 to now for the world, we have trends that are very strong. These trends are large animals are removed by humans, and small animals are left. For the sea, I call this process fishing down, mining food webs. The most frustrating thing is the animals that we catch are getting smaller and from lower in the food web. On average the catch is now compulsive animals lower down on the food web. So that’s one process. A second process is we are driving many systems toward a state where they only mainly consist of microbes, and jellyfish. My colleague, Jeremy Jackson, calls this the rise of slime. We had a richly structured three-dimensional system and we’re reducing it to two-dimensions. Animals are also getting short-lived. Short-lived animals are low on the food web living in a two-dimensional habitat. The water column altogether is full of murk and is more murky than before. And you have the extension of dead zones. You have a situation where you move from predictability to unpredictability, from healthy ecosystem to unhealthy ecosystem, and from exploitable ecosystems to difficult to explore ecosystems.
Interviewer: Can you put into numbers what’s happened to large fish populations?
DANIEL: I have a colleague who published a few years ago the fate of a large fish, typically tuna or a bottom fish. It takes about ten years to reduce it by eighty percent. In other words, ten years later it will reach eighty percent depletion. So twenty percent would be left. Fifteen years later, ninety percent depletion; ten percent will be left. That depletion curve is the rule, and it happens everywhere you look. It particularly happens with the larger fisheries. There seems to be a tendency, when we throw our industrial might at a fish species, to deplete it in ten to fifteen years. So that’s a given.
So all the management we do is concerned with collapsed fisheries. And collapsed fisheries are actually getting more and more abundant. If you define a collapsed fishery as ten percent of the catch that it had before, then we have now reached about thirty percent globally. The others would be optimally explored. If you project collapsed fisheries into the future, you will have a hundred percent collapse issues in 2048. Now that was published and much criticized because a prediction that precise cannot make sense. But predictions are based on the statement “all things being equal” and things don’t remain equal. Obviously there will be either an acceleration of the trend or a slowing down of the trend. But it does indicate which way we’re going if we don’t do anything. So in 2048, the fisheries will consist only of collapsed fisheries. And let’s not fool ourselves. This is a real danger because right now the fishery catches of the world are decreasing. And they are decreasing because during the ‘70s and ‘80s there were major collapses.
Interviewer What is the current status of the fish population in terms of marine bio-diversity?
DANIEL: We are at the threshold of major extinctions. Many species in the ocean have seen their population decline and eradicated. Populations are in many cases incipient species, separated groups of animals that produce by themselves. A species might consist of, say, ten populations. In many cases, only the most productive, most abundant population is left. All the smaller populations around the central population are gone. And really to extinguish the species, you have to extinguish only its last population. In many cases, we have reached and are exploring that last population. So I would say the fisheries of the world are poised before that last act.
You have to realize that fisheries are heavily subsidized. The subsidization rate is about thirty to thirty-four billion dollars per year. This is double as much as had been estimated by the World Bank. Normally when your old fish population becomes so rare, you should be losing money exploring it. But if you get subsidized, in other words if there is money transferred from the government, from the taxpayer, to you in the form of cheap boats, cheap fuel, cheap advice on where to find the fish and so on, then you can catch the fish even though they are very rare. You can also catch fish that are rare as by-catch of other species. You fish for species A and you catch species B, which is very rare — which is maybe even threatened as in the case of turtles. That’s the reason why fish are threatened, because it’s cheap to fish them and they are not the target of the fishery. They are the by-catch. And when by-catch fishes are caught, people also have the impression this is not a great loss; it’s just a rare species. But rare species is what a species always is before it’s extinct. A species can start out very abundant. It has to become common and less common and rare before it can be extinguished. All species become rare before they are extinguished, even species that are very abundant. Also, a species is extinguished only when you repeatedly cannot find it in its range. But that implies that you’ve sampled it and that you know about a species that you don’t find. That means you must be an expert in recognizing such species so that you know when you haven’t found it. Generally, it takes about forty years before a species is accepted as extinct. So how many species are extinct or almost extinct that we don’t know about?
Interviewer: Given the current trends, what is the worst-case scenario?
DANIEL: The worst-case scenario is called the sixth extinction. Throughout the history of the earth there have been five major extinctions and that defined the transition between different epochs. The best known one is sixty-five million years ago when the dinosaurs were wiped out. Now this was not the biggest of them all. The permian extinction was more important. It wiped out ninety-five percent of all species on earth. I think that in the extinction sixty-five million years ago, only about sixty-five percent of the species were eradicated. Five of the extinctions were natural. Most probably they were due to big meteors hitting the earth and generating such an explosion that you had fires and earthquakes.
Right now there is an extinction. Now this extinction is different. It is over a period of one hundred years. The habitat destruction — fragmentation and destruction, harvesting of birds, harvesting of reefs, overfishing, and global warming if we let it grow the way it looks that we’re going to let it — this intentional and unintentional destruction is going to terminate the job. That extinction could affect lots of species. In fact, some people have estimated how much that would be. At present it is about twenty-five to seventy-five percent of species of plants and similarly for animals. And that depends on what scenario you’re willing to accept as probable about the future. Business as usual certainly would see most animals and plants, especially large animals such as sharks go extinct. It’s almost a philosophical question that says what will happen in twenty years? What will happen in thirty years? Will we be able to maintain this bland belief that we can continue with anything? That I don’t know. But with business as usual, lots of fish will go.
Interviewer: Are there things we can do that will avoid this disaster?
DANIEL: There are things we can do and there are reasons for optimism. Essentially the subsidization rates cannot keep up with the price of fuel. Then the price of fuel really hits hard. And some of the fuel-intensive fisheries operations go bust. So you cannot go fishing, for example, far offshore with your gear if you’re only going to catch a small amount of fish. That is one reason for optimism. Another reason for optimism is the fact that most species are coastal and so each country can do a reasonable job managing its fisheries without affecting the others. That’s not true for tuna, obviously, and large sharks and so on, but some things are regional or local even. But it’s not an optimistic picture if we consider global warming, if we consider acidification. I think we have to bite the bullet and say unless we tackle the issue of global warming head on, unless we tackle head on the issue of acidification, the future looks grim.
Interviewer: What are the solutions for a better future?
DANIEL: One solution is to deal with carbon emissions. Another would have to deal with preserving habitats and life where it is. That is, we have to create large bases in the sea equivalent to national parks — marine protected areas. Right now the service area of the ocean that is protected, that is now minimally protected, with a declared area, that is point six percent of the world ocean. That is including the Great Barrier Reef and including the great area that has been declared by President Bush- off of Hawaii. Including those giant areas, it’s still point six percent of the world. The areas under protection are growing at about four to five percent per year. Now, four to five percent per year implies a doubling time of about fifteen years. So if you double the area under protection- not effective protection but under nominal protection, you get one point two percent in fifteen years. This is much too small to protect anything. On land we protect about ten to fifteen percent. Most countries protect ten to fifteen percent of the forests, of the wild land. And in the water, we don’t protect anything really. That is really an important thing — that we don’t protect any water area. So put differently, we can fish on ninety-nine point four percent of the ocean. And yet, the recreational fishermen, when we say we need a marine protected area, they freak out.
On land, you protect Yellowstone. You cannot hunt caribous, you cannot hunt animals there, but you can fish. So the idea of protecting fish is counter to our deepest feeling. But we must protect fish if we want to have them. If we want to have fish in the future to eat, fish to contribute to diversity, if we want to have marine habitats intact, if we have the provision of so-called ecosystems services in the sea, we must give them at least as much protection as on land we give to land animals and land plants. And that implies a much larger chunk than we have been up to now considering. And, again, we nominally protect point six percent of the ocean. Ninety-nine point four percent is fishable. This is absurd.
Interviewer: What needs to be done so that by the year 2050 or 2100 so we haven’t lost everything?
DANIEL: One thing that needs to be done is stop the subsidies. The U.S.A. is actually playing a very positive role there in international organizations. An alliance of several countries, including New Zealand and Australia and the U.S.A., have advocated a reduction of fishery subsidies. That would cause those exploiting collapsed stocks to go bankrupt right away. And that would help because the pressure would be reduced on the stock and it could slowly rebuild. Subsidies is a key point. Another is marine protected areas. In California I understand there has been lots of work on stocking the fisheries when they’re on the way to being depleted: turning the Monterey Bay Sanctuary into a real sanctuary, because it had been a sanctuary in name only. You could fish; you could troll; you could do anything you wanted except explode nuclear bombs in Monterey Bay Sanctuary. But now the sanctuary has turned into a thing that will be properly named. There will be no trolling, which is very destructive. That is the kind of thing we can do. The U.S. is actually taking such an initiative seriously. And it is, in relative terms, doing better than a lot of other countries, particularly the countries of the Far East, but it could be doing much more.
Interviewer: Do we have to stop fishing totally or do we just have to stop fishing in certain areas?
DANIEL: I think that fishing can continue in the areas that it has already occurred — where there has been lots of trolling. Fishing should continue to supply people with good, healthy protein. But there should be a network of marine protected areas to ensure that some money stays in the bank. Basically that’s the idea. You put some of your money in the bank so that not everything will be at risk.
Interviewer: If we want to keep some money in the bank, could we just stop fishing for certain types of fish everywhere instead of having designated areas where we wouldn’t fish?
DANIEL: No. Fishing for certain types of fish is tricky because it’s not possible to design gears that have no effect on the non-target fish. That’s the problem of by-catch. For example, you can put hooks in the sea designed to catch tuna- and they catch a lot of tuna, but they also catch a lot of dolphin, a lot of turtles, and a lot of sharks. That’s the reason why drift nets, for example, have been banned; because they caught lots of fish that were targeted, but they caught such immense amounts of by-catch that they had to be banned.
A troll, which is dragging a bag against the ground, is not selective. So they might be fishing for cod with a troll, but they also catch all kinds of things that were not aimed at. That’s one reason. And the second reason is the habitat. There are all kinds of animals that live on the ground, whose role it is to consume the uneaten plankton that falls on the ground, that are devastated every time a troll goes over them.
These animals take hundreds of years to grow — gorgonians and sponges and corals — are devastated. So you cannot have a little bit of fishing because a little bit of fishing, for example, one time a year, is enough to prevent the growth of anything that requires a hundred years to grow. So imagine, you would fish every month or every second month. Imagine you would log Yellowstone, every second month. No, no, that’s too much — every third month, every fourth month. It makes no difference. You cannot log in Yellowstone if you want trees. You could say every three hundred years – that would make sense. But every three hundred years is the same as closing it forever because three hundred years is forever in human affairs. So the idea is to close certain areas off. Imagine you have a sequoia, this big redwood, and it needs a hundred years to grow. If you want sequoias, you cannot have occasional harvesting. You cannot regulate that you can have only small chainsaws. That doesn’t work. You can only have no chainsaws. And that’s why the idea of marine reserves is so hard to get into the heads of people, because they think that the sea is like a meadow. A meadow you can harvest regularly and the plants still grow because they have a lifecycle that is compatible with being cropped. But sequoias don’t and rockfish don’t. The sturgeon that we get on our east coast could not sustain any fishing because some of them take thirty years to become mature. And a fish that needs thirty years to become sexually mature is not a fish that you can exploit with the kind of fishing machine that we have invented and which reduce stocks within ten years.
Featured Scientists Bio: E.O. Wilson
Edward O. Wilson is University Research Professor Emeritus and Honorary Curator of Entomology at Harvard University. He is one of the world’s leading authorities on ants. As a writer (more than 20 books, including “The Diversity of Life,” “Biophilia,” “Naturalist,” and “The Creation”), ecologist, and environmentalist, his work has had a profound impact on the public understanding of biodiversity loss and humanity’s role in the planet’s ecosystem. Prof. Wilson is the recipient of the National Medal of Science, the International Prize for Biology, the gold medal of the World Wildlife Fund, the Distinguished Humanist Award from the American Humanist Association, and the Crafoord Prize from the Swedish Academy of Sciences.
Featured Scientists Interview: E.O. Wilson
Interview with Edward O. Wilson
Interviewer: Tell us about your early life, when you first realized you were going to be a naturalist.
EDWARD: I became a naturalist probably at the age of 9. I became so devoted to it that I decided even at early as that, 9 or 10, that I was going to be an entomologist when I grew up. I just loved bugs. Of course, most kids are interested in them. Kids do have a bug period. Some never grow out of it. And I was one of those that never did. The interest in insects was compounded by a fascination with wild environments. As a little kid I read about these places in the world where explorers go and naturalists have adventures and discover beautiful butterflies and beetles and so on. At that time we lived in Washington, D.C. I had the added advantage of being close to the National Zoo, so close to our apartment in Washington I could walk over to it with my butterfly net and collect butterflies in Rock Creek Park around the zoo and spend long hours in the zoo. That’s the way I wanted to spend my life. And that’s the way I feel today. I just never changed.
Interviewer: What is the feeling that you get when you go into a tropical forest?
EDWARD: The feeling that I have when I walk into a tropical forest, especially the extremely rich rainforest of the continental areas, is probably very different from what others get. I walk in as a scientific naturalist, as an entomologist, as a specialist on ants. I have a very specific search image, that is, I start looking for certain kinds of insects, usually ants, because that’s what I do my research on. And, of course, in a tropical forest, I’m immediately rewarded. I often don’t go more than 100 yards in from the edge to become completely occupied with what I’m doing. On the periphery of my image of searching is a never diminishing sense of wonder about the variety of life that is there. And the evidences of it having been built up over millions of years into a multi-tiered architecture of living forms. It’s commonly said that rainforests have three levels: an under story, a mid level of trees, and then a towering upper story that has most of the canopy that captures sunlight. And each one of those levels has its own life forms, but when you explore that, as you’re able to explore it, then that’s just the beginning because then there is the brown level. The level of soil and litter, enormously rich fauna and flora of bacteria, fungi, and other organisms responsible for the decomposition of all that vegetable matter that falls down on it when branches are broken or leaves die or fall off. The combination of those four levels in a highly productive, one might say, almost over-heated system is awesome to the naturalist and to the tropical biologist and contains within it the explanation of the tropical rainforest which, although they cover only six percent or so of the earth’s land surface, are believed by most specialists to contain a majority of the species of plants and animals in the world. So you are entering a treasure house when you go into a tropical forest. I know that’s not the way most people see it. They’re looking for parrots and monkeys. And they’re a little scared of maybe encountering a snake, although they rarely do. Or maybe something like a jaguar, but eventually everyone could come to appreciate the tropical rainforest in much the way that I do.
Interviewer: One of our programs is focusing on Stewart Davies, who is making catalogues of trees in twelve different areas around the world in forest research sites. Would you make a connection for us between this incredibly rich ecosystem as a whole and the trees? What is the role of the trees?
EDWARD: The role of the trees in the tropical rainforest is pretty much the same as in forests in other parts of the world. That is, they have come in a forest environment to dominate the capture of the sunlight energy. So in that sense they are super competitors. If there is enough moisture and the soil conditions are right, the trees and shrubs will grow. The woody vegetation will dominate. So that’s one aspect of them. You wouldn’t think of them as having a particular role in the ecosystem that makes them distinct from grasses in a grassland or even lichens on an Arctic tundra. But the fact is that having created a spectacular three-dimensional structure by being dominant, where trees and shrubs can be dominant, they enormously enhance the variety of habitat available to herbivores, to insects that eat plants, both for food and also for shelter. And upon the insects then, one can base a growing number, a large number of other creatures: spiders and other insect predators and larger animals; lizards, birds, mammals, that can feed on the insects and on the birds and then on the fruit of a wide variety of kinds, so that the forests are able to control photosynthesis, a good part of it, but at the same time they’re providing a home and a source of energy for an immense variety of creatures that depend upon the plants. And that is one of the explanations for the great diversity found in forests.
Interviewer: What about trees in a tropical forest?
EDWARD: The trees in a tropical forest are multi-layered. We speak of them in rather hazy terms, but in a manner that is illuminating as being in three layers, but certainly in multiple layers. Let’s say three. Roughly the under story, which is about the height of a person or a little bit more, and then the middle story of trees, of somewhat small size. And then the towering trees of the upper canopy, that create the upper canopy. That division into layers provides a wide variety of niches for other organisms that include epiphytes, like orchids, gasneria, and so on, and the creatures that live in them and on them. It includes even space at different levels and degrees of solar energy capture of organisms that live only on the leaves on what are called epiphylls, little miniature woodlands of moss and lichens. In those are other creatures or small insects and mites and so on, found only in those epiphylls. You get stacked, one upon the other, different levels of energy in the energy flow, and niche differentiation so that species can specialize to a very fine degree. This is made far possible, especially by the structure of the tropical rainforest. It’s part of the reason why rainforests are, in fact, as far as we know, the repository of more than half of the plants and animals species on earth.
Interviewer: Why is it important to start by looking at the number of the species of trees in trying to assess the health of an entire ecosystem?
EDWARD: Very generally we expected from theory, from theoretical calculation, and now have confirmed by experiments, both in the laboratory and the field, that the more species of plants there are, the more stable the environment, the more productive it is, and the greater the number of niches it can provide for animals and other kinds of organisms. There’s a common sense element to this: the more species you have, the more likely you’re going to have an insurance policy for the whole ecosystem. In other words, let’s suppose that one tree species is very important for the functioning of the ecosystem. It can be something as in, for example, a mangal forest, which has an obviously very small number of species. Or it can be a rainforest where just a small number of species provide a large part of the canopy and are responsible for much of the animal diversity. If one species becomes drastically reduced or extinct locally, if you have many species, then there are other species that can fill in. This is known as the insurance policy, or the insurance principal of tropical and other forests.
Interviewer: Why should we care about the health of the tropical forests?
EDWARD: I would argue very generally we should care about the health of any ecosystem, yes, even the very sparse ecosystems of some deserts, or parts of the Arctic or Antarctic, but I think we need to pay a special attention to the tropical forests because that’s where most of the diversity of life is on earth at the species level. And we should look at it not just for the economic return that the close study of all these species and development of many kinds of products that we can anticipate coming from their study provides. But also because of the stability of the regions in which they live. It’s been estimated, for example, that in the Amazon a very large percentage of the rainfall is generated by the forest itself. The rainfall keeps the Amazon moist. So if you cut back too much of the Amazon forest, then you might very well reach a tipping point in which the remaining forest is not receiving enough rainfall, and it too will fade away, and with it can change the entire climate, and probably not favorably because most of the soils there are poor. So we need those forests to hold the cap on the existing world of land environment. We don’t know what crazy and destructive directions local climate and soil conditions and rainfall and so on, will move in if we destroy too much of the forest. But then, you know, there’s the spiritual reason. For heaven’s sake we’re talking about most of the creation in these forests! If we measure it, say, by different kinds of plants and animals and microbial organisms, do we really want to see these forests continued to be destroyed? The species that are in them are often millions of years old and have taken almost unimaginably long periods of time to evolve, to be adapted to one another, and to create unique genetic combinations and unique physiology and unique life cycles, and so on. Every time we allow one species to go extinct, and they’re going extinct at a pretty high rate in the tropical forest today, we’re erasing a million years or so, maybe a little less, maybe a lot more, of genetic evolution and the unique products of that evolution. We’re losing it often without even knowing it was ever there.
Interviewer: Can you draw parallels between the human impact on tropical forests and the human impact on coral reefs?
EDWARD: Very similar. Coral reefs have been called the rainforest of the sea, and probably they do indeed collectively have more kinds of organisms, mostly animal and symbiotic algae that live in the coral combined, but lots of other life forms, microscopic especially. And so the coral reefs of the world are like a rainforest, and an especially rich and precious resource. They, too, are disappearing due to human action from action change; they’re overheating corals, and that apparently causes bleaching. But also it’s just outright destruction from pollution, from dynamiting to collect fish and from building material of all things. It’s like dynamiting Notre Dame to be able to get enough rubble to build a supermarket nearby. It’s awful. But that’s happening to the rainforest at least the same rate worldwide as it’s happening to the tropical rainforest.
Interviewer: What’s your feeling about our whole fishing industry in terms of the riches in the ocean?
EDWARD: I think it’s a source of astonishment to the world to wake up maybe as early as a couple of decades ago and learn that we really could fish the seas out. And that is what we have done. We have driven down the major food fishes of the world drastically, so the average size of the fish being taken in is dropping. We kill them off before they can grow up and be big! And, of course, some fish species have been driven to what’s called commercial extinction, that is, they’re no longer producing sufficient income for the fisherman who specialize on them to pay off. Others are being relentlessly pushed down to that level, and the extinction of some species is imminent. In one case that I know of, the barndoor skate, a huge ray-like animal that reaches six feet across, is extinct. It’s been wiped out of its habitat on the North Atlantic as a by-catch. It wasn’t hunted deliberately, but these fish get caught in nets and they have been reduced apparently to extinction. So it can happen. We are drastically changing even the open sea as well as the sea bottom, particularly the shallow sea bottom, in ways that are going to be difficult to recover. Bottom trolling is roughly the equivalent of, not only say, cutting a forest, but plowing the land. And a large part of the shallow, or continental, shelf bottom has been altered by dragging nets over it. This is the destruction of the places where the species not only live, but also they spawn. So we are destroying them and we’re destroying the cradle that produces them. And furthermore, our removal of wetlands, marshes and mangal swamps especially, which are the birth places and breeding areas, the nursery areas for young fish and other marine life, are being destroyed at such a rapid rate that this is going to have a big impact not only locally where they are, but also out to sea and along the ocean floor.
Interviewer: Why is it important to know what we’re doing in terms of this kind of destruction? Why do we have scientists going out and counting species and looking at how many have disappeared and measuring the rainforest?
EDWARD: Well, if we don’t know what’s there, how can we manage our own affairs in a way not to destroy the base of our life, which is a healthy environment, a healthy living environment, especially. To not know what the species are and to try and to plan ways of making use of the biodiversity in these ecosystems as well as protect them for long-term sustainability – we have to know what they are. There’s a close parallel, it’s like trying to do medicine by not knowing what people look like inside. You can do it with witchcraft and luck, but you’re not going to get very far.
Interviewer: What do you think the future holds in terms of the environment, looking 25-50 years from now into your crystal ball?
EDWARD: I’ve often said that I’m cautiously optimistic and people immediately challenge me and say, how could you be any kind of optimistic. And my answer is reading trends and also having some faith in human nature. As Abba Eban, Israeli foreign minister, once said in the middle of one of these Mid-east wars, and it’s my favorite quote, “When all else fails, men turn to reason.” So I have a lot of faith in human beings and their desire not to destroy the world, and a lot of moral ineptitude, it should be remembered, is due to poor planning rather than innate wickedness. I think people are innately good, but they tend to be terrible planners so they get themselves into situations when they do bad things. I believe that’s the situation we’re in right now in the environment, so I say that the signs are, we are waking up, the world is waking up. People around the world are now generally aware of important environmental changes, led by climate change. That’s accepted in most places. And they are aware that species are going extinct at an accelerating rate. And they understand that it’s not a good thing if we destroy the rainforest and coral reefs. In fact, it’s a very bad and dangerous thing. And this rising awareness, I think, can be read as a trend, which is a source of optimism. The question is, will we wake up? Will we reach a tipping point, and I hope there will be a tipping point where this becomes part of the global ethic in time to avoid real catastrophe in terms of climate change that will affect all of us, and in terms of mass destruction, possibly up to half the species on earth, say, by the end of the present century.
Interviewer: Is there a danger that we’ll wake up and it will already be too late? Is that human nature?
EDWARD: The question is, will we wake up to the environment crises and actually mobilize ourselves and our resources to stop it, slow it anyway, and then eventually stop the deterioration of the environment. And note, it’s not just a matter of achieving this, of curing an ongoing pathology, human environmental pathology. But also it can be a very substantial source of new wealth. As we learn more about life on earth in particular, we have more sources of wealth available to us. And as we develop the technology to preserve the environment and turn the environment into a sustainable system, then a new technology and new sources of wealth will be available from that. That’s always been the case with human economic growth, in the industrial age particularly, and now the post-industrial age. So I think we have a good chance of catching it in time. I’m particularly interested now, personally, in enlisting religious believers. I think we have — I mean by we, the secularist scientists who have provided the information of what’s happening and generally have been the leaders in raising the alarm about what’s happening — they have done so as a minority without really taking the right steps to enlist engagement of the rest of the people. It’s an amazing fact to me that there are 30 million members of the National Association of Evangelists in this country and then large numbers of other evangelicals, and then still larger numbers out there of people of other denominations in the Judeo-Christian realm, particularly in America, versus 5000 members of the combined three largest secular humanist organizations. It’s the secular humanists who seem to be the cutting edge for the most part for our environment. My belief is that maybe we should be looking for an alliance here. Stop worrying about who knows about science, stop worrying about what the differences are in religious interpretations, and the culture wars over evolution and other religion versus secularism disputes. Put that aside, for heaven’s sake, and realize that science and religion are the two most powerful social forces in the world. That the vast majority of Americans, for example, are intensely religious, or are at least comfortable with religious beliefs, and guide a lot of their lives by religious beliefs directly or indirectly. And try to understand that these are not dumb people. They are very smart people. It’s just that they have a different worldview from the secular scientists. I think they’re fundamentally environmentalists. They want a clean, healthy environment for themselves, I’m sure, and their children and their grandchildren. And I’m sure too, that if you just put it to them plainly, yes, they don’t want to see the creation, that is, the biological diversity of the world wiped away carelessly. And if we could get together on that one ground of paying attention to the living environment and doing something really as a people to solve the problem, we would solve it.
Interviewer: We have a few small bright spots on the horizon which we can talk about, for example, the Yellowstone ecosystem – the Yellowstone National Park and its surrounding areas – where they reintroduced the wolf. Would you talk about how, just in terms of an ecosystem, how adding back something like the top predator that was taken away, can open up all these possibilities for everything else and bring back balance?
EDWARD: Introducing a wolf brings the ecosystem back, since it’s a top predator, to something like its original balance in the sense that now the herds of elk and other herbivores are cut back and then we know that they can be at least in a rough balance, with fewer herbivores. Then, with the herbivores kept in control to some extent, you have an improvement in growth of a lot of plant species that were otherwise being trimmed back to very low levels. So a single species sometimes, can make a huge difference whether it is present or absent. It should be borne in mind that those ecosystems in the Yellowstone and surrounding regions evolved for tens of thousands or hundreds of thousands of years to have a wolf in them, a wolf species in them. So you take it away, then you’re in a condition that has not existed before, and you’re going to throw it out of balance. An even better example, one that’s more spectacular, is the sea otter, off the Pacific coast of North America. The sea otter was hunted down to near extinction because its fur is very valuable. When that happened, it turned out that we had explosions of the sea urchin population because sea otters feed to a large extent on sea urchins, these little spiny creatures that are all over the bottom of the ocean. And because now there were so many of these little invertebrate animals on the sea floor, we witnessed the destruction of the kelp beds, the natural vegetation, pretty much like wolves in the Yellowstone. So that one species being cut back by human activity eliminated a lot of the kelp forest, and large numbers of species of animals that live in them along much of the Pacific coast.
Interviewer: Another example we mentioned is the sea turtle and sea grass.
EDWARD: There are a lot of examples. You don’t have to look far to find many examples of what we call keystone species, that is, species that if removed or in the case of invasive species, insect pests for example, can change an entire ecosystem. That’s why we need to know a lot about the ecosystem and the species in them and be able to monitor and hopefully even predict what happens if we take one out or put one in.
Interviewer: What can we learn from the past that will help us now and in the future?
EDWARD: In evaluating environmental change, historical and even archeological records are invaluable. That’s the only way that we can find direct evidence of what has happened in the last few centuries or even in some cases, all the way to a thousand years. For example, thanks to historical records, we know now that as recently as 2000 years ago in the Roman era, the Mediterranean area was much more forested. You could walk from Carthage to Alexandria in a shade of trees. North Africa was not the searing desert it is today; it was a savannah with wild animals of the kinds you now find in East Africa, including elephants and lions and all these things that were captured and shown off in the Roman Coliseum. And go over to Hawaii – – now that’s history – – go over to Hawaii and you discover that before the first Polynesians arrived, that’s the first humans who arrived around 400 A.D., that there was something like 125, maybe 150 species of birds native to Hawaii. And they were spectacular. There was a flightless ibis, there was a Hawaiian eagle, there were giant goose-like birds, and a wide variety of other birds including, particularly, the beautiful honeycreepers. We know from archeological records that they were there, that is, going back a few centuries or millennia, and that they disappeared pretty promptly, a large percentage of them, when the Polynesians showed up. And we know that many more disappeared after the Europeans and other colonists came in starting in the 18th century. Those records tell us not only the extent of the damage of human activity, but they tell us quite precisely which species disappeared. We know those species only by remnants, sub-fossil, the material in the archeological excavations.
Interviewer: What is the importance of the places that we’re saving to the future of mankind?
EDWARD: Reserves of natural environments -natural environments of the world – are shrinking fast so we’re setting aside some and we need a lot more. We need to ensure that there are wilderness reserves as well. For example, for tropical forests you can still have wilderness-size reserves in the Amazon, the Congo basin, and New Guinea. We need these for a variety of reasons: environmental stability, the economic potential of having a sustainable environment, and so on. But I think we also need them for the human spirit, and let me just put it in terms of a very fundamental principal that most people I hope would agree with. Humanity needs choices. Human beings — and this will be true down indefinitely into the future — humanity needs and deserves the choice of visiting natural areas in which the human species evolved, and to which we are more akin and spiritually attached than most people realize. If we completely humanize the world, then there is only that choice. If we leave these reserves and include wilderness areas in them, where you can enter and see the planet as it was before humanity began to transform it, then we have a choice. And we know from a mass of evidence that now includes psychiatric, post surgical recuperative care, trends in architecture, interpretations by historians, and on and on, that there is a very strong need for humanity to have natural environment. The wealthiest people in the world take note. They use a good portion of their wealth to be able to go to these areas and they have their own habitations there, in them or on the edge of them. We should allow humanity as a whole and humanity on into the future to have no less. As a simple precaution we should not let an irreplaceable resource, human resource if you want to call it that, the natural places in the world disappear. Because once they’re gone, they’re gone forever.
13.1 Looking Forward: Our Global Experiment Video
Earth's essential systems are being stressed in many ways. There are many tipping points in the environment, beyond which there could be serious consequences. Will human ingenuity, resiliency, and cooperation save us from the worst outcomes of our global experiment?
Unit 1 Many Planets, One Earth
Astronomers have discovered dozens of planets orbiting other stars, and space probes have explored many parts of our solar system, but so far scientists have only discovered one place in the universe where conditions are suitable for complex life forms: Earth. In this unit, examine the unique characteristics that make our planet habitable and learn how these conditions were created.
unit 2 Atmosphere
The atmosphere is what makes the Earth habitable. Heat-trapping gases allow ecosystems to flourish. While the NOAA Global Monitoring Project documents the fluctuations in greenhouse gases worldwide, MIT's Kerry Emanuel looks at the role of hurricanes in regulating global climate.
Unit 3 Oceans
Oceans cover three-quarters of the Earth's surface, but many parts of the deep oceans have yet to be explored. Learn about the large-scale ocean circulation patterns that help to regulate temperatures and weather patterns on land, and the microscopic marine organisms that form the base of marine food webs.
Unit 4 Ecosystems
Why are there so many living organisms on Earth, and so many different species? How do the characteristics of the nonliving environment, such as soil quality and water salinity, help determine which organisms thrive in particular areas? These questions are central to the study of ecosystems—communities of living organisms in particular places and the chemical and physical factors that influence them. Learn how scientists study ecosystems to predict how they may change over time and respond to human impacts.
Unit 5 Human Population Dynamics
What factors influence human population growth trends most strongly, and how does population growth or decline impact the environment? Does urbanization threaten our quality of life or offer a pathway to better living conditions? What are the social implications of an aging world population? Discover how demographers approach these questions through the study of human population dynamics.
Unit 6 Risk, Exposure, and Health
We are exposed to numerous chemicals every day from environmental sources such as air and water pollution, pesticides, cleaning products, and food additives. Some of these chemicals are threats to human health, but tracing exposures and determining what levels of risk they pose is a painstaking process. How do harmful substances enter the body, and how do they damage cells? Learn how dangers are assessed, what kind of regulations we use to reduce exposures, and how we manage associated human health risks.
Unit 7 Agriculture
Demographers project that Earth's population will peak during the 21st century at approximately ten billion people. But the amount of new cultivable land that can be brought under production is limited. In many nations, the need to feed a growing population is spurring an intensification of agriculture—finding ways to grow higher yields of food, fuel, and fiber from a given amount of land, water, and labor. This unit describes the physical and environmental factors that limit crop growth and discusses ways of minimizing agriculture's extensive environmental impacts.
unit 8 Water Resources
Earth's water resources, including rivers, lakes, oceans, and underground aquifers, are under stress in many regions. Humans need water for drinking, sanitation, agriculture, and industry; and contaminated water can spread illnesses and disease vectors, so clean water is both an environmental and a public health issue. In this unit, learn how water is distributed around the globe; how it cycles among the oceans, atmosphere, and land; and how human activities are affecting our finite supply of usable water.
unit 9 Biodiversity Decline
Living species on Earth may number anywhere from 5 million to 50 million or more. Although we have yet to identify and describe most of these life forms, we know that many are endangered today by development, pollution, over-harvesting, and other threats. Earth has experienced mass extinctions in the past due to natural causes, but the factors reducing biodiversity today increasingly stem from human activities. In this unit we see how scientists measure biodiversity, how it benefits our species, and what trends might cause Earth's next mass extinction.
unit 10 Energy Challenges
Global energy use increases by the day. Polluting the atmosphere with ever more carbon dioxide is not a viable solution for our future energy needs. Can new technologies such as carbon sequestration and ethanol production help provide the energy we need without pushing the concentrations of CO2 to dangerous levels?
Unit 11 Atmospheric Pollution
Many forms of atmospheric pollution affect human health and the environment at levels from local to global. These contaminants are emitted from diverse sources, and some of them react together to form new compounds in the air. Industrialized nations have made important progress toward controlling some pollutants in recent decades, but air quality is much worse in many developing countries, and global circulation patterns can transport some types of pollution rapidly around the world. In this unit, discover the basic chemistry of atmospheric pollution and learn which human activities have the greatest impacts on air quality.
Unit 12 Earth’s Changing Climate
Earth's climate is a sensitive system that is subject to dramatic shifts over varying time scales. Today human activities are altering the climate system by increasing concentrations of heat-trapping greenhouse gases in the atmosphere, which raises global temperatures. In this unit, examine the science behind global climate change and explore its potential impacts on natural ecosystems and human societies.
Unit 13 Looking Forward: Our Global Experiment
Emerging technologies offer potential solutions to environmental problems. Over the long-term, human ingenuity may ensure the survival not only of our own species but of the complex ecosystems that enhance the quality of human life. In this unit, examine the wide range of efforts now underway to mitigate the worst effects of man-made environmental change, looking toward those that will have a positive impact on the future of our habitable planet.