Arquivo de etiquetas: Biodiversidade

Antropoceno XXIV – A Fronteira da Perda da Biodiversidade

Biodiversity loss

It may surprise you that biodiversity is one of the planetary boundaries. But when one sits down and reflects a bit it becomes very obvious that biodiversity must be one of our planetary boundaries.

Think of it, without the living species everything from vegetation, trees to animals and small insects, pollinators, we would have no biomass, there would be no carbon sequestration, there would be no rainfall because a large portion of our fluxes of water originate from the canopy, from vegetation transpiring and evaporating water back to the atmosphere. It regulates the flows of fresh water, regulates the flows of carbon, nitrogen and phosphorus.511

The living biosphere is a fundamental component in regulating the stability of the entire Earth system. And this relates to two components. One is the genetic diversity; the treasure of genetic code, which forms the adaptive capacity of the entire Earth system. But it’s also the diversity of functions that we know today that in order to develop, for example, food for a world population of 7 billion people we need the functions and landscapes for pollination, the function of microorganisms in the soil to develop organic matter which in turn delivers nutrients for plants, without which we would have no food.

So we need to explore the functional diversity and the genetic diversity in the rich treasure of living species on Earth. And this forms part of a core fundamental part of a living planet. The drama is that we’re really mismanaging biodiversity in the world. In fact we are today, based on the observations we have, in the sixth mass extinction of species in the world, the first extinction to be caused by another species, and one of these six, for example, being when we lost the dinosaurs 65 million years back on Earth.512

So these are big, dramatic changes, illustrated here for example when it comes to how we’re dealing with global fisheries. Just over the past sixty years from the 1950s and the onset of the great acceleration when we started the exponential rise in pressures on planet Earth, you see here the extraordinary social-ecological journey of not only increased landings of fish, but also that fish efforts are changing dramatically from small scale fisheries to large scale industrial fisheries where we are basically vacuum cleaning large tracts of oceans, not only in shallow waters but also in deep ocean regions.

We have the classic examples of collapse of fisheries; like the cod fisheries off the shores of Newfoundland, where we’re learning unfortunately that once we cross a tipping point with regards to loss of fisheries we can actually lock the system in a situation where the fish does not even come back.513

So these are big, dramatic changes that we need to incorporate in our understanding of the resilience of the Earth system. We also have interactions between species.

This is an example of how delicate the system works in terms of relationships between seabirds and fisheries. A large synthesis across essentially all marine systems across the world shows that when we overfish and lose more than 30% of fish stocks that has an abrupt impact on seabird populations which go through, and cross a threshold leading to abrupt changes in populations. So loss of one species in this case over-fishing, has a propelling effect on seabird populations which risk collapse, in fact, in many parts of the world.514

So again the risk of not connecting diversity in species and thereby not understanding that this can lead to propelling effects across the world. A fundamental, very essential part of our own future is of course the ability to produce food. And there’s another example of how a function in ecosystems simply provides us with a free service, namely pollinating insects.

And here’s one example of a global concern among farmers, scientists, citizens in general, that we’re losing pollinating bees at a very rapid pace, to the extent in fact that some agricultural regions are collapsing. We have human beings have to step in and function as human insects to pollinate apple orchards in China. We have examples of collapse of pollination in some parts of the UK, United Kingdom, because of overuse of pesticides which led scientists to pop over to neighboring countries in Scandinavia and try to borrow bumble bees to be used as pollinators in their own agricultural systems.515

So again, understanding that biodiversity – without biodiversity we cannot have modern agricultural systems, and therefore we get locked in an undesired state in terms of delivering human well-being.

So in summary, what occurs is the recognition that biodiversity is fundamental for the regulation of the Earth system, it’s fundamental for human well-being. We tried based on this evidence to identify what could be a good control variable, an indicator for a planetary boundary on biodiversity?

We took as a first starting point an indicator that maps out the rate of extinction, how many species we’re losing, over time. And this indicator called the extinction rate per million species per year, which is a good indicator of the pace of loss of biodiversity.

The natural background rate of loss is roughly one species per million species per year, that’s the normal background rate. We estimate as a first guess that a boundary lies somewhere between ten and hundred lost species per million species each year. So the boundary was placed at ten species lost per million species per year. Now today we’re losing species at roughly ten to hundred times faster that rate. That’s why we can today say with quite a high degree of confidence that we’ve actually transgressed and are in a danger zone on biodiversity.

But we’re also exploring to understand an even better indicator for biodiversity because extinction rate only gives us a measure of diversity, it doesn’t give us any measure of the functions biodiversity plays.

And here I’ve just given one example of how the science it is advancing in terms of mapping out the functions that biodiversity plays for humanity.

This is illustrated from another index that is called the mean species abundance, which is an average measure of not only the number of species in each ecosystem in the world, but also how many in each species group we have grouped in terms of functions.

And here you have a map of the world of the situation, the state for biodiversity in terms of species abundance in the year 2000. And you can see in red the hotspot regions where we are truly in a very risky zone in terms of losing too much of species abundance. But in green you have regions that are still in a safe operating space.

And here you have the projections into the future, up until 2050, of the risks if we do not transgress ourselves, or if we do not move ourselves, into a safe operating space in terms of safeguarding biodiversity.

We’re right now working very actively in improving this analysis even further to say that extinction rate is a good measure of the diversity and richness of species in the world, but we’d like to have a better measure to measure and to determine the functions that biodiversity plays for human well being.

And one of these indices is a very exciting new advancement on something called the biodiversity intactness index, which is an even better measure on functional groups for the role played by ecosystems for human well-being.

And this is something that will be hopefully developed further and much more broadly in the world because so far it’s used in just a few ecosystems in the world.

But overall, in summary, biodiversity as a key for human well-being, biodiversity as a key for regulating the stability in the Earth system.

Science shows clearly that biodiversity is key to regulate a world that remains in our desired Holocene-like state, and science can now put the first quantitative estimates of a safe boundary within which we have a high likelihood of being able to rely on biodiversity, the richness of all species on Earth, as a support for human development.

Antropoceno XXIII – As 4 fronteiras silenciosas


In last  five posts we’ve gone through the big planetary boundaries of climate change, ocean acidification, and stratospheric ozone depletion. Naw will  be covering the remaining six planetary boundaries.

This is a really exciting module where we will be exploring the boundaries on biodiversity loss, freshwater use, land use change, our interference with the global nitrogen and phosphorous cycle, aerosol loading, and novel entities of chemical pollution.



Antropoceno XXII – A Fronteira do Ozono

All life on Earth depends on the extraordinarily thin layer of livable atmosphere which envelopes the biosphere in our Earth system. But above the atmosphere in the high atmosphere, roughly ten to fifty kilometers above ground, we have the stratospheric ozone layer.464

And the stratospheric ozone layer is a protective shield that enables life on Earth by reflecting back harmful ultraviolet radiation from the Sun. So clearly the ozone layer is a planetary boundary enabling human prosperity and development on Earth.

The stratospheric ozone layer has for a long time been understood as being absolutely essential for living conditions on Earth. And in the early ’80s scientists started to observe something absolutely extraordinary namely a rapid, abrupt drop in the thickness of the ozone layer.461

This was a huge surprise, in fact scientists even thought it was an error in the scientific observations. But through fantastic research by top scientists in the interface between atmospheric research and chemistry soon it was proven that the reason for this depletion was that certain chemicals that we used as refrigerants, as solvents, propellants, the whole family of chlorofluorocarbons were moving up the atmosphere through high winds and reacting with ozone and – and breaking these molecules apart and thereby depleting the stratospheric ozone layer, threatening life on Earth, and particularly health for humans, by risks of rising skin cancer, cataracts and damage also on vegetation, food production systems on Earth.463

This led in the mid-1980s to the extraordinary step where the world gathered around a protocol, the famous Montreal Protocol, to ban chlorofluorocarbons from use in refrigerators. And this in turn has led to a success story where a boundary of ozone depletion was transgressed in the early ’90s and now we’re actually moving into a safe operating space, showing that humanity in fact can collectively as all nations on Earth work together to operate within a safe operating space.463

So we are moving in the right direction on ozone, but what is very important to recognize is that we’re still observing an ozone hole, particularly over the polar regions, and the classic ozone hole is in Antarctica, which is due to the combination of ozone depleting substances, continued emissions of chemicals, but also the fact that the sins of the 1980s are still haunting us because of the delay time in much of these chemical reactions, which is also a reminder that, uh, we need to apply the core thinking of planetary boundary theory which is a precautionary principle, because what we do today, which we sometimes do not even understand, can have a harmful effect on the Earth system, can actually come back and hit us many, many decades later.

I’ll give you a small example that comes from the Nobel Laureate Paul Crutzen, who was one of the three scientists observing the depletion of the ozone layer in the early 1980s. The industry at the time had a choice of two molecules to develop the refrigerating chemicals that were used worldwide, either chlorine or bromine. And just so happened by pure coincidence that the industry chose chlorine. That was very lucky for humanity because it just so happens that chlorine has several magnitudes lower harmful effect on ozone. If the industry in the early ’80s instead has chosen, or rather in the early ’60s all the way up to the ’80s when we banned the chemicals, had chosen bromine as the carrier of refrigerating systems across the world we most likely would have had a catastrophic tipping point that would have undermined human development on Earth.464

So that’s an example of how close we were of what we can call a planetary scale disaster, and why thinking in terms of defining planetary boundaries is so essential. Science has come to a point where we are at a position where we can define a control variable, which we have chosen as the thickness of the column of ozone across the planet.

And this gives us a very good, robust, science-based definition of how much we must maintain in terms of ozone, and thereby also translating that to avoiding chemicals that can destroy the ozone layer.

Is the problem finally resolved? Well the answer is unfortunately no. The most damaging chemicals used in the early ’80s are not on the market any longer, but we’re using other types of refrigerants, and methane is a compound that also poses a threat to the stratospheric ozone layer, and we see other emerging novel entities that could actually threaten the ozone layer, reminding us that planetary boundary processes do interact, and one very strategic way of protecting the ozone layer is also to have a strong boundary on chemical pollution.

Antropoceno XXI – A Fronteira da Acidificação dos Oceanos

We’ll be talking about ocean acidification. What I’d like to do is touch on three things, first the chemistry of ocean acidification, the consequences of ocean acidification, and some of the connections, not just in the planetary boundaries framework but outside that as well.

So let’s start off with chemistry. The first slide here shows the carbon dioxide budget globally, and it comes from the Global Carbon Project based in Australia.451

And towards the left you can see the amount of carbon dioxide emitted by human activities like fossil fuel burning or cement production. That’s the arrow, the big arrow, going upwards. There’s another upward going arrow and that comes from the carbon dioxide emitted from land use change.

Of all of the carbon dioxide we emit to the atmosphere about half of it stays there, and that’s why carbon dioxide concentrations are increasing. But what happens to the other half? Well, about 25% or so goes into terrestrial ecosystems, that’s the downward going arrow to the trees, and the other 25% ends up going into the oceans.452

So what happens when you dissolve carbon dioxide in the oceans? Well the carbon dioxide forms a compound with water called carbonic acid, which then dissociates – that means it splits up and forms two ions – a proton H+ and a bicarbonate ion HCO3-. That can dissociate again, giving off another proton and a carbonate ion. And each time a proton is added to water it becomes a little bit more acidic. So, is that a global issue? Well, yes it is.

This particular image shows three different plots of ocean pH as a function of time.

The one on the far left is a pre-industrial case. And the color coding is proportional to the ocean pH, so you can see that the red colors are about 8.2, green colors are 8, the purplish-blue colors are 7.8-7.9.453

And you can see in the pre-industrial case most of the oceans were 8 or above in terms of pH. Present day it’s still around 8, but there are fewer areas which are above that. Predicted for the end of the century you can’t see any places at all with pH of 8.

Now that doesn’t sound like much, right? But keep in mind that a tenth, the 0.1 pH unit, is about a 26% increase in acidity of the oceans. So we’re talking about a lot. What are some of the consequences, uh, of ocean acidification?454

Well this plot shows a lot of different kinds of marine organisms, and it’s not so important, you can take a pause and look at more detail, but what you want to – to concentrate on first is increasing ocean acidity is going to the left in these plots, and calcification rate, that’s how rapidly organ– organisms in the ocean turn carbonate into a – into a shell is on the vertical axis going up.

And most of these plots either have a little bit of a – an inverse U-shape or it’s just going down, which means that most organisms in the oceans don’t like it when it becomes more acidic, they slow down the rate at which they make a hard shell out of the carbonate in the oceans. What does that mean really?

Well if you’re a coral reef you’re under stress from ocean acidification and other things like ocean warming and different kinds of pollutants. And you can go from the kind of beautiful, vibrant, very bio-diverse reef you see on the right to the kind of bleached reef you see on the  left as a result of those changes in the ocean, including ocean acidification.455

What are the implications and how rapidly can this happen? Well the graph on the top shows predicted increases, in carbon dioxide concentration for the atmosphere under a number of different scenarios into the future.

The bottom shows the aragonite saturation, that’s the point at which the equilibrium shifts from making aragonite, a kind of calcium carbonate, a soluble or an insoluble compound in the ocean, and that you can see will happen by the early mid-century for the southern ocean under most all of these scenarios into the future. So the point at which aragonite becomes soluble, or coral reefs might have a very, very difficult time, uh, existing at all, will be about mid-century or so, not too long from now.456

Now that’s not the only stressor that marine organisms are facing. It’s one of the more important ones, but if you look at some of the other ones, like ocean warming, and other kinds of pollution you can see that the oceans are facing multiple stressors.

And in particular, on this plot, if you looked at the hatched areas, much of the southern ocean and much of the north Pacific and Atlantic oceans, will be faced by a number of stressors including, uh, ocean acidification. And all of the organisms that live there will be in a much more stressed environment.458

You can get more detail about this, and other issues as well, in a book, Managing Ocean Environments in a Changing Climate. It tries to put all of these different stressors together and tells you how they fit with each other.

Which moves us into the connections part of the presentation. So you’ve seen this picture before, or at least some version of the picture.

This is the image of planetary boundaries. It’s not by chance, that ocean acidification and climate boundaries are right next to each other, because the driver for both is the same, how much carbon dioxide we emit to the atmosphere.

So this next to the last slide shows some of the connections between planetary boundaries, ocean acidification and the couple of other things, like food production. So you can see on the top we can produce food from terrestrial sources or on the bottom we can produce food from marine sources.

And the things that connect them are our planetary boundaries. So you see chemical pollution, for instance, from production of food on land might negatively influence coastal areas where we farm or fish, uh, for food. And nitrogen and phosphorus cycling, and what we’ve been talking about so far in terms of ocean acidification, the amount of carbon dioxide that we emit into the atmosphere.

And the important thing with this slide is to realize that all of these processes are fundamentally connected with each other.

You can’t really pull one apart and look it all by itself. Having said that though we’ll like to do a little bit of a reminder of what the ocean acidification boundary actually is.459

It’s written in terms of aragonite saturation, that is, it’s a chemical equilibrium, and this might be a poster child for planetary boundaries in the fact that that’s a very, very easy boundary to define, because it is a chemical equilibrium.

If you add a little bit more carbon dioxide to the oceans aragonite becomes saturated, or unsaturated, so this is probably the easiest to define of all the planetary boundaries, and you can see on this slide exactly what it is.

Biodiversity IV


Forests remain one of the major parts of terrestrial ecosystems on the planet. e know that forests cover something around 30% of the total land area.

And we also know that forest cover used to be a far higher proportion of, the earth’s land area, before humanity got to it[1].

1341Humanity’s been in the business for thousands and thousands of years of clearing forests. And we read accounts of the massive deforestation in ancient Greece, or in the Roman Empire, or in ancient China and India thousands of years ago. This is an ancient story, but we continue to lose a lot of rainforest, and a lot of other forest areas today, because of the increasing populations and pressures on the planet and the forces of international trade. So what has been going on from ancient times, continues and in some ways, intensifies, till today. When we lose forests, we degrade ecosystems. We also lose a tremendous amount of biodiversity. Our rainforest areas, the three great rainforest areas of the Amazon basin, the Congo basin, and the Indonesian archipelago, are home to countless species and much of the greatest biodiversity on the planet. And as those rainforests are being depleted right now, or are at threat of massive deforestation and degradation, we are also losing huge amounts of biodiversity as well. This map gives us suggestion of the extent of past deforestation, and some of the challenges of current deforestation. Every area shaded in this map, is an area that originally had forest cover.

1342The very light shaded areas, let’s say in western Europe or across China, or across Russia and, the Eurasian land mass. The light shaded areas in the eastern half of the United States, are areas that were original forest cover that have been deforested. So western Europe, much of the eastern half of the United States, essentially all of China, lost its original forest cover to human activity. In the case of China, hundreds of years ago that process was already complete. India as well having lost a huge amount of its original forest cover. Europe having lost a huge amount of its original forest cover hundreds and in some cases thousands of years ago. Today, most deforestation is taking place in the fast growing tropical and subtropical regions. And notably in the rainforests where population densities were low traditionally.

But had been rising and where these rainforest regions are increasingly being encroached for human provisioning, for tropical log woods, or for clearing, for farm land, and for pasture land. Or for provisioning of peasant small holders who go into the forests for fuel wood, or for bushmeat or for other needs of people living on the margins, of the forest. And the result is that while temperate zone areas were deforested in historical time, it’s now the tropical areas that are under the most direct force of deforestation today. Not because there’s something intrinsic about tropical deforestation, but rather, in a way, from a historical point of view, because it’s coming last in line. It’s a, set of ecosystems that were relatively less disturbed previously, but now are facing major disturbances in human impacts. Some of that human impact is internally driven by growing populations within countries, within Brazil or within Central Africa for example, or in Southeast Asia. But, a huge amount I’m going to want to draw our attention to, is coming from international trade.

From demands halfway around the world for these forest products and this is very, very difficult to control because it means high levels of demand, often from rich countries or rapidly growing economies like China. Even overwhelmed local protective services. It’s easy to bribe. It’s easy to engage in illegal activities even when they are on the books under legal control. This map that you’re looking at now shows us the current patterns of deforestation. It emphasizes that in areas that were traditionally deforested, say, the eastern part of the United States or western Europe, or northern Europe, there is some reforestation taking place in those areas. That’s a very healthy point. But the red areas shown on this map are areas that the Millennium Ecosystem Assessment identified as being areas under a current intensive process of deforestation. And that includes parts of the tropical rainforests I’ve mentioned. Large regions in Southeast Asia. Of course the Andean region as well. Many parts of the world where there are remaining forests find those forests under threat. Forests are major providers and regulators of ecosystem services, and this means that the threats to these forests are threats to human well being. And it’s worth listening to the words of one of the great scientists of our age, James Lovelock who is the creator of the Gaia theory which is basically the theory of the interconnectedness of the world’s ecosystems and the interconnected regulatory processes of those ecosystems. Lovelock more than, most earth scientists, 30, 40, 50 years ago, emphasize the interconnectedness of the climate regulatory functions. that, and other natural flux functions of energy heat dissipation nutrient flows, and so forth, played by ecosystems. Emphasizing that when we degrade one ecosystem, we impede or undermine the functioning of ecosystems in other parts of the planet. So here’s what Lovelock says for example about the deforestation of the tropical rainforests. He says, and I’m quoting, no longer do we have to justify the existence of humid tropical forests on the feeble grounds that they might carry plants with drugs that cure human disease. Because he’s saying that was one argument that conservationists were emphasizing. Maybe the main one. Don’t cut down the rainforest, there maybe a lifesaving medicine there. There’s proof to that, but what Lovelock is saying is that’s not the only proof. Gaia theory forces us to see that they offer much more than this. Through their capacity to evapotranspirate vast volumes of water vapor, they serve to keep the planet cool by wearing a sunshade of white reflecting cloud.

1343So the rainforests have cloud cover above it. A lot of that cloud cover reflects the incoming ultraviolet radiation, sending it out into space, rather than having it hit the earth, warm the earth, reradiate as infrared. And so, the changing reflectance of the planet, caused by the existence of the rainforests is a regulatory feature of climate. Not intuitive, not of our everyday nature, but recognized by an interconnected earth systems science. So, Lovelock concludes their replacement by crop land could precipitate a disaster that is global in scale. The point, the point is that when we degrade large ecosystems such as tropical ecosystems, the impacts can be far more then we would recognize in the absolute direct impact of the loss of the local ecosystem services. Earth systems science teaches us that the interaction of the ecosystems in their global regulation of climate, water cycle, other nutrient cycle, nitrogen fluxes, are also of huge significance for planetary balances and for human well being. Well, the extent of degradation is enormous. The pressures are vast, and the pressures are coming from many different directions. Have a look at the island of Borneo, which is shared in the present day, by Malaysia and Indonesia. Malaysia, with its two states of Sabah and Sarawak. And Indonesia with the state of Kalimantan. This island is absolutely under the most incredibly rapid and deep transformation, because one of the most diverse, wondrous ecosystems of forest area is essentially being cut down and replaced by monoculture, for palm oil production. Palm oil is in huge demand, since palm oil is a very versatile product. It commands a good market price. It’s used in many home products. It’s used in cooking and for for home use. And it’s soared, in demand in recent decades.

And the maps that you’re looking at produced by UNAP, both show the actual decline of forest cover on the Island of Borneo. Up through the year 2005 and then projections that were made under a business as usual trajectory for 2010 and 2020. What you’re observing here essentially is deforestation to replace a highly biodiverse rainforest area with a monoculture of of palm oil. Now palm oil in limited production is okay and when it’s carefully monitored and measured and kept within certain boundaries, it can make sense. But if it sweeps the island of Borneo and as is similarly taking place in Sumatra and Indonesia, if you get a massive replacement of a diverse ecosystem with a monoculture, the losses will be phenomenal. The losses to regulatory functions of these ecosystems. The losses to biodiversity in the specific context of Indonesia, Malaysia.

1344Huge threats to the loss of, again, one of our closest Great Ape relatives, the orangutan whose habitat is precisely in these rainforest areas, whose numbers have declined, and whose habitat is under tremendous threat. And unless we take into account what is a sustainable harvesting of tropical forests. What is in the same way that we need to take into account the sustainable harvesting of fisheries, and other ecosystems. We will, before we know it, have lost these ecosystems. They will have fallen into an irreversible collapse. There’s an attempt to do something about it of course. In fact there are several attempts. One that is notable, is to link the conservation of the rainforests, and forests in general, with the climate change agenda. Because remember that perhaps 15% of the total carbon dioxide emissions each year are coming from land use change especially from deforestation. And so, the idea was taken several years ago that as part of the mitigation effort, not only should we be reducing our carbon footprint in the energy sphere, but also the carbon emissions coming from deforestation. And the project that has grown up from that is called REDD Plus, R-E-D-D Plus. Which stands for Reduced Emissions from Deforestation and Forest Degradation. And so, it’s both the thinning of forests and the clearing of forests that are the target of the REDD Plus Initiative. The idea, and it’s a good one, is to give financial incentives to farmers and to communities and to forest communities in general, often including indigenous populations. To protect the forests and to replace part of the income that in the short term they would lose from their over exploitation of the forest products, with a sustainable flow of income of other kinds including a top-up of income being provided by donor countries. Norway for example, has offered a billion dollars to Brazil. In a REDD Plus Initiative to slow or stop the deforestation of the Amazon, [COUGH] and to use this funding to create financial incentives for forest communities in the Amazon to play the role of protecting the Amazon rather than facilitating its loss. The map that you’re seeing here are the participating countries. The countries in red are countries that are actively receiving from the United Nations, support for developing REDD Plus programs. Other partner countries are shown in blue. It is a, an important effort. The funding by some countries like Norway has been extremely generous. But, it’s still a small counter pressure to an overwhelming force coming from the global marketplace for the products, either directly off the forests themselves, or for the products that are grown. The meat products or the soy beans or others that are grown, when the for, and palm oil, when the forest are cleared and replaced by other kinds of economic activity. Let’s look in more depth at programs like REDD Plus to see what the international response is to the loss of bio diversity. To see how that response is functioning to date, and to make a kind of assessment of how we might and need to strengthen that response, if we are to reverse the very powerful wave of species extinction and ecosystem loss that now is engulfing so much of the planet.


Biodiversity III

Oceans and Fisheries

As we’re putting pressure on ecosystems of all kinds, polar, alpine, tropical rain forests, dry-land areas. We’re of course, also putting tremendous pressures on our marine eco systems and the oceans.

We know that we’re changing basic ocean chemistry. We know that we are poisoning the oceans with the pollution of coming from huge oil spills and other disasters and we are also degrading the biodiversity in the oceans through human activities, especially through the over fishing and over harvesting of marine life.

1331The oceans cover three fourths of the Earth’s surface area. And we know, of course, as we discussed many times that, our huge cities around the world hug the oceans, depend on the oceans for trade, for economic activity, for our food supplies, for our proteins, and, Invaluable, nutrients such as omega-3 fatty acids from, our fish intake. Back in 1950, the estimate is that the total ocean catch measured, in total metric tons was somewhere, around, 20 to 30 million metric tons of fish catch. By 1990, that had become around 90 million metric tons that perhaps a factor of three or four increase globally in how much we were taking from the oceans.

1332And that is even an under estimate of the true effect, because those numbers, as conventionally reported, don’t measure what we discard and throw back in the oceans. When fishermen catch fish in the nets, they also bring in a lot of bi-catch, or unintended catch, of marine life that they don’t want. And that’s not counted in the, harvesting of the fish, but it is an absolutely core part of the actual, over harvesting of marine ecosystems. You’re looking here at a fascinating graph which has a very important message and reality to it. The blue area shown here is the capture from the oceans, it’s the amount of fish taken, and marine life taken, in metric tons year by year. And it rose sharply, as I said, up to the 1990s. And then more or less leveled off. You might say that’s a good thing. But in a way it was force majeure in the sense that, that leveling of reflects the collapse of many fisheries around the world that had increased the takes so much that they had driven the fisheries to depletion, to crisis.

1333So that the amount that could be taken out was, was limited, increases were no longer possible and in many cases such as the, near, my former home when I was a professor at Harvard university up in New England. A complete closure of the cod fisheries because of the collapse of the cod fisheries after so much heavy fishing for so many decades. So that leveling off is a reality that came from the enormous pressures being put on ocean fisheries. It doesn’t mean that we’ve reached an equilibrium because many fisheries around the world continue to be driven towards  depletion. And our, in a situation of crisis. Now on top of that is another green area of rising production of aqua-culture. This is going to managed fisheries, not in the open sea catch, as in a traditional fitching, fishing, but in raising fish industrially either on the coasts in many cases or in inland areas that are suitable for growing fish. China is the world champion of aquaculture. And as the limits to the marine catch have intensified, the markets for aquaculture have expanded. And that has permitted a continuing overall rise in the metric tonnage of fish that are consumed. That’s a good thing overall, because, of course, this is, a reflection of the fact that, fish are highly desired in our diets, and highly nutritious as well. But it also poses a whole new chapter of risks, for us, because aquaculture itself has huge impacts on ecosystems. The cultivation of fish in managed locales at the coastline or in fish farms in in the interior Can lead to spread of disease, can lead to excessive nutrient flows of many kinds, can threaten the biodiversity of wild fish through escaped varieties from managed fisheries in aquaculture and so forth.

1334But what the diagram shows is that we are hitting limits of the open sea catch, and compensating in part and on the whole, in a desirable way, through aquaculture. But only if that aquaculture itself is operated in a responsible matter, and that is a complex challenge given all the things that can go wrong with aquaculture. Now, how did this massive increase of catch occur? It came from a massive increase of fishing activity. Shown here, comparing the intensity of fish fleets in different fisheries around the world in 1950 and in the early years of this new century. And what you see is a massive expansion in the magnitude of the fleet coverage in this period. There were huge technical advances in the use of massive long line nets, which allowed for much greater capture, in the use of all kinds of remote sensing, satellite imagery and other kinds of sensing to identify where the fish are located in the use of ocean bottom trolling. to, that just scrapes up the fish on the ocean floor and other marine life, often completely devastating those highly complex, highly bio diverse marine ecologies as a result of all of this. And so, the consequence is that technological advances, as is often the case, has not been the friend of biodiversity and of ecosystem sustainability.

1335It has led to a huge depletion of fisheries, a huge loss of biodiversity, and a huge threat to the productivity of these marine ecosystems. One measure of how big the catch is, is an innovative measure that has been developed, that looks at the amount of photosynthesis needed to produce primary food products for the amount of fish take that is being and marine catch that is being harvested from the oceans. And so, one looks at the amount of primary production implied by the fish take as a fraction of the primary production in that fishery area as an indicator of risk. In other words, how much photosynthesis is being appropriated for the fish catch. Just as we looked when Professor Vetusak asked how much of the terrestrial photosynthesis is being appropriated for the human species. And we found the shocking number that it’s 40 to 50% of the net primary production. Well, the same thing is true for the amount of fish that we’re taking, so this is, again, human appropriation. Of net primary production, but indirectly, in the form of the fish take, and what you can see in these red areas, shown on this map are fisheries where the amount of net primary production associated with that amount of fish capture is already an endangered zone. 30% or higher in many cases of the total net primary production being, taken, in fish catch each year, implying that we are harvesting at a rate that is completely unsustainable for these fisheries.

1336Now, one implication of this is not only are we driving the abundance of fish down to levels that threaten their very survival, but we’re also changing the structure of the ecosystems as well. It’s called fishing down the the trophic chain or fishing down the food chain. Because the first fish to go are the high trophic fish, the large blue fin tuna, and others that are the big prized carnivorous or pacivorous fish that eat other fish, that eat other fish, that eat the plankton. And the net primary producers weigh down the trophic level and what, the fish ecologists, have done is to measure the average trophic level of the fish that are caught. Meaning, are we mostly harvesting fish that are the first, on, on the first line of eating, the photosynthetic output or are we catching fish up the food chain that are the, predators of the fish lower down. And what we find in, from the evidence provided by, the ecologists, is that over time more and more of the catch is lower and lowered down the trophic chain. And the reason is that humanity is very good at eating those prized fish, way up the food chain.

The predators of the predators of the predators and we value those fish, we catch them, we deplete them, they’re smaller in number and they’re highly valued and then, later on, we go to smaller fish and lower down on the food chain. And this is shown by these two downward sloping lines which measure, over the years, the average trophic level of the catch that is brought from the fisheries. The top blue line in this chart is for the marine fisheries and the red line lower down is for fresh water fisheries. And what’s superimposed on this is aquaculture where we’re growing fish that are higher up the trophic level. Now that is also complicated.

1336When we grow, in agriculture, fish that are high up the fish chain. It means those fish have to be fed smaller fish. Or fish meal and that means that that kind of aquaculture requires massive open sea fishing to provide the fish meal. To feed the, the growing aquaculture, and so, in this way, aquaculture maybe doesn’t substitute for the open, open sea excessive harvesting, but actually can exacerbate it if we are feeding piscivorous fish in the aquaculture. To the extent that the aquaculture is for fish that are that, that eat photosynthetic output rather than other fish, herbivorous fish. Then we don’t have that phenomenon. And, those kinds of aquaculture. For instance, tilapia, us, is a substitute rather than, a, an amplifier, of the, the, pressures on the open sea fishing. Now, the, the basic framework that fisheries ecologists use is a framework that asks how much can be taken sustainably. And they calculate or try to calculate a complicated concept of maximum sustainable yield of a fish type. And the question that they’re asking is, how much tuna can be taken from this fishery or how much anchoveta can be taken from this fishery or how much cod can be taken from this fishery without depleting the fish stock? And the basic question is, at what natural rate is that particular species, for example growing, within this ecosystem?

1337So that if that amount is harvested, it’s leaving that amount of species, unchanged year to year, and therefore in a stable population. The basic idea of calculating the maximum sustainable yield is to try to determine what is a safe level of fishing. That concept has become more complicated necessarily in recent years, because ecologists came to understand it’s not good enough to ask, for an individual species, how much can be sustained.

1339We have to take an ecosystem-wide perspective, so now the ecologists are calculating a maximum sustainable yield, based not on a single species framework, but on an ecosystem wide sustainability concept. Now, the most essential point is that humanity continues to fish more than the maximum sustainable yield. And thereby drive more and more of the fisheries into danger of depletion, ultimate collapse, even extinction of, certain, fishes, that are, depleted, and, and then driven to extinction. What can be done about it? Well, the key point is clear. One has to put a limit on how much fish can be taken. And this has led to many kinds of policy innovations, none of which is foolproof by any means, because these market pressures are relentless. But to try to identify the maximum sustainable yield and then assign permits for that amount of fish catch. And in some cases, to allow those permits to be traded, among individual fishermen, in which case their individual fish quotas. Or among groups or companies. But a kind of tradeable permit system, where the total number of permits given is in correspondence with what the ecology tells us is a sustainable amount of fishing is the main policy direction that has been taken. But, with all of the lobbying pressures, more quotas, don’t tell us there are limits, with all of the illegality of unmonitored, and undocumented, and illegal fishing these systems have in some cases shown results. But in other cases have essentially been brushed aside by legal and illegal forces, political and economic that have meant that the depletion has continued despite the attempt to put on these kinds of limits. Well, if the oceans were troubled only by the extent of harvesting of marine life, we’d have trouble enough. But it’s important for us to remember that the kinds of assaults of humanity on marine ecosystems is coming from many, many different directions. This map is showing the corals at risk along the coasts of the world and emphasizing that the reasons for this risk are multiple, as usual. Tourism over fishing, over exploitation of the coral reefs. Harvesting of the corals themselves using dynamite for fishing, pollution sedimentation, human activities driving corals also to depletion to threat of extinction for many coral species because of climate change and direct impacts on the coral reefs all over the world. This map is showing what we’ve mentioned many, many times, and that is, the run-off of nitrogen and phosphorus, leading to eutrophication and to hypoxia, to dead zones. Depleted of oxygen along the coasts of the rivers. Look at the entire eastern coast of the United States and the Gulf of Mexico coast of the southern United States, especially where the Mississippi river enters the Gulf of Mexico, the massive amount of dead zones there. Similarly, we see that in the North Sea. We see it around China and Korea and Japan. We’re there’s a tremendous amount of eutrophication taking place. And this map, we’ve seen before, is the step by step acidification of the oceans as the high concentrations of CO2 dissolve in the oceans. Create H2C03, carbonic acid, that acid attacks the shellfish, the calcareous species in the ocean, threatening whole classes of marine life. We’ve got huge problems we have some tools to address these. But I think the fair summary is that our oceans are at profound and still growing threat because of the pressures of human activity. We depend on the oceans in countless ways for our well being, for our survival. If we don’t take care and face up to these multiple assaults. We will face a growing crisis in, the not so distant future.

Biodiversity II

Biodiversity Under Threat

Ecosystems provide vital services for human well being, provisioning and regulation among them. Biodiversity, the variation of life within species, across species, and across ecosystems.

1321Determines to an important extent, how well ecosystems perform. And therefore, how well they provide vital services for humanity. There was a long standing hunch that a greater degree of biodiversity. More genetic variation within species a richer web of species in a food chain or in a given ecosystem, would raise the performance of ecosystems. And over the last 20 years, ecologists have been making valiant efforts to understand the linkage of biodiversity to ecosystem functioning. Their conclusion is a very strong one. And that is that biodiversity, biological diversity, raises the performance of ecosystems in valuable ways. And when biodiversity is under threat, at any level of organization, less genetic variation within a species, less variation of the range of species, less favorable interaction across ecosystems. When biodiversity is a threat, ecosystem functions are degraded.

Let me give just a few examples of what has been found as reported recently in some overviews of this linkage, from biodiversity to ecosystem functions. Consider provisioning, for example. The way that ecosystems provide food or fiber for human needs. One thing that’s found is that crop yields are higher in farm systems that have a higher biodiversity. This is a very big deal, because a lot of the industrial food production is monoculture. One kind of crop grown massively on a farm, rather than a high biodiverse farming system. And even within, that one crop, whether it’s rice, or wheat, or maize or, some other crop, it’s one seed variety perhaps, industrially manufactured.

1322And so what’s happening is that the biodiversity of our farm systems is shrinking. And one of the findings is that this is making our farm systems less productive. Yields actually go down. And maybe farmers don’t know this individually, or they haven’t had the experience, or they’ve become part of an industrial food chain that has discouraged a highly biodiverse farm system, but the results are farms in threat. And farms that are monoculture are also far more vulnerable to the invasion of pests and pathogens. One of the things that biodiversity does is protect an ecosystem from an invasion. In invasive species like a weed variety, or in invasion of a pest that attacks a certain kind of plant.  If there are multiple kinds of plants in the ecosystem, maybe there’s some loss, but the parasite or the pest is controlled. But if there’s one monocle through it can tear through the entire area without limit essentially. So the resistance to invasions, to parasites, to pests is also reduced. Another finding quite similar is in marine ecosystems.

If there is a reduction of biodiversity of the fish species. And that’s happening all over the world as fishermen clear a particular fisheries area of the most favorite species, or particular easy to catch species, or the fewer numbers at the higher trophic levels of the ecosystem, meaning the kinds of fish that it, that eat other fish, that are piscivorous that are fish eating fish and higher up on the food chain. In other words, the phenomenon has now been verified by ecologists across many different kinds of ecosystems and many different kinds of reductions of biodiversity. also, when it comes to implications for climate regulation, reducing ecosystem performance by lo, a loss of biodiversity also can reduce storage of carbon in cycles, or in plant life.1323And therefore, essentially, releasing carbon dioxide into the atmosphere because there’s less biological sequestration of the carbon within the ecosystem. So the regulatory functions of ecosystems in climate as well, are degraded when biodiversity is lost. Now, that’s all pretty bad news, and the reason it’s bad news is that in ecosystem after ecosystem, biodiversity is at massive threat. It’s already being reduced, degraded, hugely threatened. Why? For so many reasons that it’s going to be extraordinarily difficult to bring under control. A summary perhaps that’s useful is to look at a map of the world that was prepared by my colleagues at the Earth Institute a number of years ago, called the Human Footprint Map. What my colleagues did was to take a number of indicators. For example, population density, land use change, infrastructure coverage railroads, roads, other human changes. Aggregate them, weight them in an index, and then for each small part of the world, the kilometer by kilometer ask, how big is the human influence, the human footprint in this part of the world. And they came up with a map that looks like this. The darker the red, the stronger is the human footprint. If an area is all green, that’s a part of the world very little touched by human influence.

1324Well, what you see in this map is the sweep of humanity. Humanity is basically everywhere where it’s habitable. And so you look at the United States there’s no dark green area essentially in the continental United States. The eastern half of the U.S. is much darker red than the western half because it’s much more densely settled. In part because it’s it is more humid, there is more food production and the western part of the United States by and large is arid and more mountainous, with much less population density. But even there, the human activity, land use change, pasture land, farm land, urban settlements, roads, rail, are pervasive. So where are the dark green areas? well, in Africa, the desert, the Sahara desert. Yes, very, very low human impact, but very, very few people living in the Sahara. For the boreal regions of the Eurasian landmass. Up in the tundra. where there are still forests and very little population because it’s frozen much of the year or year round. And there’s not agriculture in these very high latitudes. And so there’s relatively low human impact. But look at India. Look at China other than the Tibetan Plateau at 20,000 feet or more above sea level. Look at South America aside from still parts of the Amazon rainforest.

1325What you see is the pervasive human footprint. Humanity is everywhere. And just like the underlying index that is the basis of this map, humanity is everywhere in many, many  different ways. It’s there in infrastructure, it’s in farming. It’s in changes to basic chemical cycling, as we’ve talked about so much in water use, or nitrogen cycling, or phosphorus cycling, as a result of agricultural activities. Now, a related idea was led by a great ecologist, Peter Vitousek. now, more than 15 years ago, when he and his colleagues asked the question about human domination of the ecosystems. How much are we taking in that provisioning. We need food. We need pasture land. We need areas to to, to put our asphalt down for our cities and our roads, and our parking lots. How much of the global ecosystems is humanity appropriating? What is the human domination? Their conceptual framework for that is shown here in this complicated flow chart. They start at the top with human population both its size and the resource use. Then, the human enterprises, they called it, what humanity does in agriculture and industry and recreation in international trade. Then they talked about the several ways that human activity appropriates or dominates ecosystems. Land transformation, for example, farming or land clearing for pasture land and for use of forests could be the change of the cycling of key nutrients and chemicals and the ecosystem as we talked about like nitrogen or the water cycle or the carbon cycle with its enormous effects on climate. Or changes directly in the biosphere. As we harvest crops, as we hunt species, as we fish for fish. Or as we rearrange the biogeography of species by saying, why don’t we take that species from Australia and put it here, without having a deep understanding of what happens when one species invades another ecosystem where its predator or control mechanisms might not apply. And all of this, if you go down the flow chart, changes the climate system, for example, through the greenhouse gases of carbon dioxide, methane, and nitrous oxide. And leads to a loss of biological diversity, which is our main focus right now. So what Professor Vitousek and his colleagues did was to try to assess how big is the human domination of ecosystems by several fascinating metrics. How much land has humanity transformed? How much have we changed the carbon cycle? What have we done to water use and so forth? Their conclusion revealed the massive extent of human impacts across all of these dimensions. Land area, 40, 50 percent of the total net primary production through photosynthesis on the planet is for us. That’s a pretty voracious species. We are grabbing and have grabbed land area. Whether it’s the pastures, the forests, the arable land. And said okay to the other species, we’ll take that, thank you. That will be our pasture, that will be our farmland, and the extent of the human reach on land transformation is perhaps half of the total net primary productivity on the planet. CO2, we know we’ve changed the carbon cycle fundamentally, and already raised the level of carbon dioxide in the atmosphere from 280 parts per million, pre-industrial revolution, to 400 parts per million and rising. Now, water use. Tens of thousands of dams put on the world’s rivers. Massive taking of groundwater for irrigation especially. Harvesting the the flow that comes from glacier melt. And that very dangerously for us is going to come to an end as those glaciers retreat and then finally disappear under the force of global warming. Water use in crisis in many, many parts of the world because we have appropriated so much. Of the the, the available fresh water cycling. Nitrogen, we know we have come to dominate the nitrogen cycle. Turning N2 in the atmosphere into so called reactive nitrogen like ammonia or nitrates and nitrates that can be taken up by living organisms, is, both a natural process as we’ve discussed but also an industrial process, the Haber-Bosch process. That famous process that enabled humanity to grow so much more food that it made it possible for the population of the planet, to rise from not quite two billion people at the start of the twentieth century, to six billion people by the end, and now 7.2 billion people. We have threatened species so much that we realize that we need to classify and measure the species, that are endangered. We need to understand the extent of these dangers. and, the International Union for the Conversation of Nature, the IUCN, is the global score keeper of endangered species. It’s extremely important to understand what they’re measuring, and how they’re measuring it. And that is shown first on this diagram which helps us to understand the classification system used by the IUCN. Now the first thing to say is that there are an unknown number of total species on the planet and theories vary roughly between ten million species of all kinds. Plants, animals, microbial life. To possibly up to a 100 million species. We’ve not classified, large proportions of those species. So IUCN, still is in the process of classification, as is the world scientific community. Of those that are classified, then there are categorizations of species that are not threatened by human activity, they’re so in, in so many places and in such large numbers that humanity does not pose threats. To those that have already been driven to extinction. And you can see here the classification that are of, of the various gradations of threat. Species that are extinct because of human activity. Species that are extinct in the wild but perhaps still live in small numbers in captivity. Critically endangered species, endangered species, vulnerable species, near threatened species, and those of least concern. So, the IUCN keeps its so-called Red List which gives the numbers of species in these very threatened categories. And you’re looking at the tables for critically endangered, endangered, and vulnerable species. And when one looks at the numbers, it’s of course, very, very frightening because even in a very short period of time, the numbers classified as critically endangered, for example are soaring. Partly this is through new classifications and adding species that have not been classified before. But it’s also very much that human activity is driving species to the state of being critically endangered and to extinction. The IUCN Red List is invaluable and of course, it is profoundly troubling. We know that major classifications of animals and plants are being pushed to the extreme, the critical danger levels and some to extinction. And just to mention, a few that are most dramatic amphibious species the world over are declining hugely in numbers. And this is taking place ac, across the range of amphibians and it’s taking place all over the world. Recent studies for the United States have shown an enormous drop-off. And one of the frightening things for the loss of amphibians in the United States is those that had the highest proportionate drop-off in frequency of sightings are the ones that were classified by IUCN as the most endangered. And so the declines of amphibious species are not taking place in the most abundant and safest but in the most endangered. Another major collapse, of of species are pollinator species which are so vital for our plants and our fruits and our food provisioning. The honey bee, in the United States, has been experiencing a dramatic, troubling and still poorly understood decline in numbers. And in some cases, a collapse of bee colonies that has come to be called the colony collapse disorder. And it is so striking with the fall of numbers. But even more striking perhaps, that we don’t quite understand why, where, what’s happening to this radical die off of bees across the United States. There are many potential culprits, Could be a parasite, a parasitic mite has been implicated, but then again multiple viruses have been implicated. Bacterial diseases. A drop of, nutrition, of, the honey bees, coming from changes of landscape and crop varieties. And many, many scientists think that it’s the increased use of pesticides that is a major cause of this. Another absolutely shocking, and dramatic, and troubling loss of species abundance and threat of extinction are the great apes. Our closest relatives on earth where humanity shares the genetic code and the evolutionary history just as close as can be. 95% or more of the genetic code shared with great apes, with the gorillas, chimpanzees, orangutans bonobos and the dramatic decline of numbers of these great apes and of their habitat in the last 25 years is absolutely shocking. I had the occasion recently to visit one group of eastern mountain gorillas in Rwanda in Volcano National Park, which is doing a valiant effort to preserve the habitat of the mountain gorillas. It’s of course an incredible experience to be together with the gorilla group and to see them in the wild. And it was absolutely rather shocking to see how fragile is the remaining habitat for these endangered gorilla groups. Because the farm land, under tremendous population pressure is pushing right up against the the cloud forests, the bamboo forests, that are the habitat of the mountain gorillas. There is a stone wall which separates the farm land from the the bamboo forest. One doesn’t go far inside the bamboo forest to meet with the groups of the gorillas. You see how close humanity and the gorillas are living together and by the way, that means that humanity can pass pathogens, diseases, human diseases to gorillas. We share so much of our biology, of our genetics of our immune systems, that the diseases easily flow in both directions and disease itself can be transmitted to these gorilla groups. Well, it was breathtaking to be together with the mountain gorilla family and and a mountain group in the wild. But it was absolutely shocking to see how humanity has pressed against the remaining habitat for this species. The, the one of the closest relatives that we have and how fragile is that distance now that that is their margin of survival on the planet. These pressures are coming in all directions. They are causing huge risks to biodiversity. The risks to biodiversity are causing huge losses of ecosystem functions, and we have to understand now what we can do about it.

Biodiversity I

What is Biodiversity?

We’ve been examining what happens, when a growing world economy collides against planetary boundaries. We have a world output now, of 80 to $90 trillion, 7.2 billion people. We know that the numbers are continuing to rise. We know that the world economy is continuing to grow at three to 4% per year, meaning a doubling, every 20 years or so. We know, that there are already huge pressures on the world’s ecosystems, on the climate, on the oceans. And we have not yet found a way of course, to reconcile that continuing growth, with environmental sustainability.

1311We’ve studied a few ways that this, collision or this trespass of planetary boundaries is occurring, climate change being the most dramatic. Pollution of the air and water and the dangers to our cities being another. I want to go into greater depth now, on the question of the viability of other species, the biodiversity on the planet. I’ve mentioned several times, that humanity is putting so much pressure on the Earth, that we’re actually causing a dramatic increase in the rate of species extinction. Maybe 100 to a 1000 times, greater rate of species extinction, than was occurring before the the industrial revolution. That loss of species and many other phenomena associated with it, such as the decline of genetic diversity within species. The decline of abundance of species, even when they’re not being pushed to extinction, but just to smaller and smaller numbers. That combined effect is so large, that it is causing what could be the sixth great extinction on the planet, as I’ve discussed, and it is causing huge threats to humanity. As always, whether it’s with climate change, or dangers to our cities, or challenges of health and education, first we need to understand, what’s happening? Why is it happening? What are the mechanisms? We have to do a differential diagnosis of the losses to biodiversity, and to the rising rates of species extinction. Then we have to analyze, what we can do about it, what’s the prescription, what are the possible approaches? Now, there’s one overriding truth to this sixth wave of extinctions and to the threats to biodiversity. And that is, that the threats are coming from many, many different angles, as is true in almost everything we’re studying. We’re dealing with a complex system, where there’s not a linear effect from a single cause to a single outcome, and then onto another effect. There are multiple stressors, multiple drivers of environmental change, multiple causes of species extinction or decline of abundance and genetic diversity. We need to understand the complexity of this system because no single approach is going to be sufficient to reversing the trends that are underway. Heading off this sixth great extinction that is a threat, to not only millions of other species, but to one that we also have a especially strong vested interest in, and that’s Homo sapiens, that’s us. And so we need to get into the very complex nature of this threat. You’re looking at an example of biodiversity, the incredible diversity of species and interactions in this marine environment that you’re viewing right now. And of course, what you see are multiple species of animals and plant life. Many species are microscopic, and you don’t see them. You see the interactions of the fish, corals, and we know the microscopic plankton for example in the oceans, with the non-living part of the system in front of you, the fluxes of energy, of sunlight of nutrients that are arriving in this ecosystem from a variety of sources. What is an ecosystem? It is exactly that collection, of plants and animals and microbial life, interacting with the abiotic or nonliving part of the local system, with the energy and nutrient fluxes.

The key is that this is a set of living organisms together with the non-living environment. Interacting in a system and of course, what ecologists do in studying ecosystems, is study the fluxes and dynamics of the system. How does nutrient flow take place within a food web and within the processes of metabolism. Of, oxidation, respiration, photosynthesis, and other basic processes of, the metabolism of the living organisms, within the system. How does the diversity of the, species and the diversity of the individual organisms within a species, affect the behavior of that whole ecosystem? So when we have an ecosystem, we’re also interested in another core concept. And that is the biological diversity or biodiversity of that ecosystem. And of the biodiversity across ecosystems, as ecosystems, marine, and terrestrial, interact with each other, to produce outcomes, at an even higher level, of aggregation and organization. So what is bio-diversity? Bio-diversity is the variability of life, and it is variability that occurs at all different levels of organization. We care about the variability of life within a species, each of us is different from from other people. We have different genetic codes. We carry different effects of our our environment. We know that the relationship of environment and genetics, is extremely complicated. We found out that it’s even more complicated than we thought, through the emerging field of epi-genetics, which tells us that the environment affects, how our genes code or don’t code, in ways that actually can transmit across generations. Even not in the DNA itself, but in the way that that DNA is expressed in cells from a parental generation to offspring. So, we care about the variation, within a species. We care about the interaction across species. All of the various relationships of predator and prey, and mutualism, and parasitism, and the ways that species interact, and live together and are part of, larger food chains and nutrient fluxes. And a part of the way that, the disease is pathogens, transmit within an ecosystem. And we care about the biological diversity across ecosystems. Because the interaction of ecosystems, of dry land ecosystems, or desert ecosystems, interacting with the humid ecosystems, with alpine or marine ecosystems, is also absolutely crucial for understanding, how any of those individual ecosystems functions, but also understanding the global functioning of the, the earth as a whole. What happens in the oceans or what happens in the polar regions or what happens in the rain forests, affects global dynamics of heat dissipation, of the water cycle, and through multiple processes, affects ecosystems all over the world. So there are distant relationships between changes in the pole-ward regions, for example. And what happens even in the tropics or, or places that are thousands and thousands of kilometers, distant. So, biological diversity or biodiversity, requires us to understand the variation of life, at all different levels of organization, and to understand how that variability affects the performance of ecosystems, in ways that matter.

One of the most important studies that was done, in recent decades in fact, on the functioning of ecosystems, was a major global effort which reported in the year 2005, called the Millennium Ecosystem Assessment[1]. It took a global view of the major ecosystems in the world, and tried to give a conceptual framing, of how they’re functioning, how they’re interacting and what they mean for humanity. And one of the important schematic ideas that came out of the millennium ecosystem assessment is, this chart that you’re looking at right now.

The idea of this chart is to define, how ecosystems affect human well-being. That’s not the only thing we care about ecosystems, but it’s a pretty important part. And you see on the left, various categories of ecosystem services, so-called. Ecosystem services are the benefits, that ecosystems give to humanity, and to other species, I would like to add. And those benefits come in a variety of forms. Partly, ecosystems directly provide for human needs. Provisioning services, growing food, providing fresh water. providing, wood and fiber for building structures, for our clothing. Providing biomass for our fuels. So, provisioning is one direct and obvious category. A bit less, direct, but absolutely profound, is the idea of regulatory ecosystem services. Ecosystems control basic climate patterns, disease patterns cycling of crucial nutrients, in ways that are of fundamental importance to humanity. Even if they’re not directly the provisions of things, that we eat or directly consume. So for example, ecosystems in their functioning, have huge effects on climate regulation. If, the pole-ward Nordic and Arctic ecosystems are heavily changed by climate warming, then we’re also going to get powerful feedbacks that could be of tremendous adverse consequence. For example, the melting of the great ice sheets. Or the decline of ice covering the seas, changing the reflectance of the planet and providing a massive feedback, amplifying climate change, coming from greenhouse gasses. Or, the melting of ice in the Tundra, releasing massive amounts potentially, of methane or carbon dioxide, in a feedback mechanism. So, ecosystems provide regulatory services, either helping to sustain a climate in a safe zone, or if these ecosystems get perturbed, amplifying adverse changes that are coming from other factors, such as greenhouse gas concentrations. Flood regulation is the second kind of ecosystem service. Coastal areas are often protected by the mangrove swamps just off the coast or by other topographical features of ecosystems, and if those get perturbed, if those are lost by human-induced changes, that can lead to great dangers. The coastal areas around New Orleans, for example, were degraded by the ways that human activity led to changes of the dynamics of the Mississippi River, as it flows into the Gulf of Mexico. And the loss of those coastal barriers meant, that when Hurricane Katrina slammed the Gulf of Mexico, this added tremendous force and damage, to New Orleans and to the rest of the coastline. And so, the loss of coastal regulatory protection because of human activity, clearing mangrove swamps or changing river flow dynamics, had a hugely consequential and adverse effect for humanity. Ecosystems regulate disease and pests, and when ecosystems are degraded, pests or invasive species,that is species that have been brought in by accident or even inadvertently, from outside a particular place and maybe don’t have natural predators within that new environment, can spread, can take over, can be essentially like wild weeds or spreading parasites, with devastating consequences to food production, for example, or to human health. The ecosystems for instance, the wetlands which are a major part of the water cycle help to provide fresh water help to replenish ground water. Vital for household use or for crop production. When ecosystems are deranged, we can lose water services needed to grow food and needed for human health. Ecosystems have a third category called supportive ecosystem services you see here. Nutrient cycling or the way that soils are formed, through the interaction of biotic and abiotic processes. And soil formation then, is a crucial underpinning of course, of our agricultural productivity. And finally, the millennium ecosystem assessment identified cultural features, which are our values, our aesthetics. One of the, greatest scientists, of our age, E.O. Wilson, the great biologist at Harvard University, one of the leaders in understanding biodiversity and one of the leaders in understanding human nature, in, in our world, has given the idea that, humanity has a deeply ingrained love of bio-diversity. That we even inherited as part of our, our, our mental baggage during human evolution. A trait that he calls biofelia or love of of a diverse of a biology and the, the bioda, and our biodiversity. And Professor Wilson has given extensive compelling evidence from the range of anthropological studies for example, of how humanity feels at home, in certain natural environments. And how the degradation or derangement of those natural environments can deeply upset our cultures, our mental well being our sense of aesthetics, our overall quality of life. Well, those ecosystem services, translate into many dimensions of human well-being, our physical security, the materials that we need for life, our human, physical and mental health. Our ability to interact fruitfully in society, in other words, there are contributors to our social capital, and to the preservation of social relations and as the millennium ecosystem assessment emphasized, they contribute to our freedom, our capability to accomplish our life’s tasks. So, ecosystem services are central, they are a threat because they are such core, dimensions to our human well being, we now have to turn to the question of, how biodiversity contributes to the functioning of ecosystems, and what happens when biodiversity is put at great threat, by human activity. That’s our next subject