Arquivo de etiquetas: Fronteira

Antropoceno XXXV – Governação Global

We probed how planetary boundaries interact, learning for example that the stability of the climate system depends entirely on the way we manage land, water, and oceans, proving that in fact the planetary boundaries seem to be like three musketeers – all for one, one for all.

We need to simply be sustainable stewards of all the components of the earth system. But we also discussed in depth that biophysical boundaries cannot guide us toward sustainability alone. We need to stay within a just and fair safe operating space, connecting the human dimension with the biophysical challenges of global sustainability.

We’ve been pulling in the latest thinking from very, very important experts in their areas, such as Kate Raworth, who developed the doughnut economy model of connecting a social floor to the biophysical ceiling of planetary boundaries.

We’ve been discussing a bit more in detail of how to reconnect human development to the biosphere and staying within a safe budget on all of the planetary boundaries.

We’ve also introduced the concept of peak everything and how resource constraints couple to the boundaries provided by tipping point analysis related to planetary boundaries.

Now we’ll move into a module focusing on governance, focusing on pathways to success and also the grand transitions we face in energy, food systems, technology, and urban areas.

I’m sure you have many many ideas of what planetary boundary thinking means for governance, for democracy, for equity, for transparency. So please do share your ideas, opinions on the forum to keep a lively discussion forward.

Antropoceno XXIX – Sintese sobre Fronteiras do Planeta

Synthesis and progress on planetary boundaries

The science on planetary boundaries builds on the remarkable advancements in Earth system science over the past 20 to 30 years. It’s an integration in the natural next step in scientific advancement between our understanding of the pressures of the Earth system, how the Earth system is a complex self-regulating biogeochemical physical system, and the recognition that if we push environmental systems too far, we risk crossing tipping point that can fundamentally, abruptly, and irreversibly push ourselves away of the stable desired state of planet Earth.561

What may surprise you is that the approach of finding planetary boundaries is illustrated very nicely in this first slide here where a Moon lander is looking at our wonderful, small, little marble Earth planet from a distance.

In fact, that’s how the analysis starts. We step out as humanity and try to understand the Earth system and ask ourselves to question what are the Earth system processes that regulate the stability and the resilience of the Earth system? And for each such process we ask ourselves what is the boundary beyond which the system could be pushed outside of a desired state?

And science shows very clearly that we know what this desired state is. And in this slide as a synthesis of that shows the ice core data from Greenland indicating the enormously jumpy ride that humanity has had throughout his entire period on Earth as modern human beings.562

This graph shows our last 100 000 years journey on Earth, until we enter the final, last interglacial period, which we learned in school to call the Holocene, which I would call the Eden’s Garden, the perfect paradise, desired conditions for us to build our civilizations and the modern world as we know it.

So the planetary boundary framework is about safeguarding the desired Holocene-like state on Earth by recognizing this state as the only state we know that can support the modern world as we know it, and from science determining the Earth system processes that regulate this state.563

And that is what led us to defining the nine Earth system processes that we know, with the best science at hand, regulates the stability of the Earth system.

And here we have of course the big systems with large scale tipping points, such as: climate change, ocean acidification, stratospheric ozone depletion. We have the four slow variables that operate under the hood of the Earth system regulating the ability of the large systems to be stable: land system change, fresh water use, the rate of biodiversity loss, and the way we interfere with the large nutrient cycles of nitrogen and phosphorus. And then we have the two processes that are so highl564y manmade: namely aerosol loading, which is all the soot and the particles in the atmosphere that cause large health challenges but also influences, for example, rainfall patterns and weather conditions; but finally of course the novel entities, the exponential growth of chemical compounds that aggregate themselves in the Earth system.

By tapping on the best science we can put quantitative boundaries that gives us in green a safe operating place. This is where we can put humanity back, to prosper, develop, evolve, and thrive within this safe operating space. That’s why planetary boundaries is a truly integrated analysis. It’s about a safe space, and by biophysical terms, but it’s about recognizing equity, fairness, and a just distribution of the remaining ecological space on Earth to enable a world of soon 9 billion people to develop and prosper.565

In my mind this is the new definition of sustainable development. It’s recognizing that global sustainability and development within a safe operating space is the new endeavor and the new goal for human development on Earth.

We’re very excited by the fact that science can now step up to, I would argue, the responsibility of providing quantitative global environmental goals of this kind. It shows in our analysis that we’re already in a danger zone on climate change, biodiversity loss, and interference with the nutrient cycles.566

This work was released the first time in 2009, and has since then led to a very large, vast set of scientific efforts of critically analyzing the quantifications, critically asking the questions whether we’ve got the nine boundaries right, and based on all the science we are working continuously updating this concept to get the absolutely best quantifications.

And a few exciting updates have occurred based on scientific colleagues around the world publishing updated work in this area. The first one is the recognition that the nine boundaries are not entirely, so to say, even in the role of regulating Earth resilience.

In fact we do identify now that three of the boundaries are what we call core boundaries. They operate and regulate the entire Earth system, and they are the endpoint depending upon how the other boundaries operate.567

So the best example of these three core boundaries is climate change. Climate change is the end result of how we manage fresh water, nitrogen, phosphorus, land, biodiversity, oceans. It all aggregates up into the functioning of the climate system. So when we use climate forcing as a good control variable for the climate system, the level of that forcing, whether or not we stay within the boundary, depends intimately whether we’re able to stay within a safe operating space for the other boundaries, to the extent, in fact, that among us scientific colleagues we talk of the boundaries as being like three musketeers, “One for all, all for one.” It seems we need to stay within a safe operating space for every boundary in order to avoid that one boundary flips over across the threshold.

The other core boundary is biodiversity. We now recognize increasingly that the genetic diversity on Earth, and the functions they play to sustain resilience and to build human well being, is a high level aggregate result of how we manage fresh water, land, oceans, nutrients, and even the climate system.568

And the third core boundary we believe is novel entities. The reason for this is that chemicals, such as everything from endocrine disruptors, persistent organic polluters, all the way to nuclear waste and loading of heavy metals, is so totally lien to the operations of the Earth system, in fact the Earth system has never seen, at least not in millions of years, the kind of human-induced artificial loading of new totally artificial compounds into the Earth system.

We’re learning as we speak what the aggregate effect of these can be on our own health, on the genetic composition of species, from birds to humans. But this is an entity of its own core right. And these three we call core boundaries.

The second development is that we’ve refined the biodiversity boundary. We call it now biosphere integrity, because we recognize that genetic diversity is one thing which we captured in the first analysis. Basically what’s the number of species on Earth, which we can measure quite well with extinction rate, which you used in the original analysis.

Now we’re much more, let’s say, sophisticated in using a new index called the biosphere integrity index, which measures not only number of species but also their functions and how many species within each function. So we can secure, for example, that we do have the minimum amount of pollinators in an agricultural landscape. And this is truly exciting giving the tools for sustainable development in the Anthropocene.

We’ve also refined some of the quantifications. And I would just like to share a few of the key developments here. And the number one is on phosphorus. In the original analysis, we were preoccupied with how much phosphorus can we load into the oceans before we risk a large scale tipping point in the oceans into anoxic, oxygen-free dead states in the ocean?

We were criticized for this. Scientists pointed out that way before you’ve pumped in so much phosphorus in the ocean that you could tip the ocean you’ve destroyed so many fresh water systems along the way of the journey of phosphorus from where it’s loaded, often in an agricultural field, to the ocean that we have tipping points occurring in fresh water systems. So now we actually have a twin definition of the phosphorus boundary.

One, which we maintained from the original analysis, which is the amount of phosphorus that we can load in the oceans. It emains in fact eleven million tons of phosphorus per year. We’re today loading eight, nine so we’re approaching the boundary. But can you imagine? The analysis shows that already at averaging at 4 million tons of phosphorus per year on what we call erodible soil, which is essentially how much phosphorus we can load on productive agricultural land, when we go beyond that number we risk large scale tipping points in fresh water systems. These twin boundaries need to be considered for phosphorus.

For nitrogen finally we took, which was a very wise decision, the valve of how much inactive nitrogen we can maximum take out of the atmosphere, and transform into reactive nitrogen which would plug into the biosphere. You may be aware that the fantastic invention of the Haber Bosch process, which produces reactive nitrogen fertilizers is the vehicle for our modern agriculture, without which we probably could not feed ourselves in the modern world. But it loads reactive nitrogen into the biosphere at an extent, which is so large that we humans are now a much larger force than the entire global natural nitrogen cycle.

We estimated in the first analysis that the maximum loading of nitrogen in order to avoid that nitrogen triggers tipping points in ecosystems was 35 million tons of nitrogen per year. It was a first best guess. Roughly one-fifth of the amount of nitrogen that we’re taking out of the atmosphere, so a dramatic decrease, and therefore indicating that we’re way out in a danger zone on nitrogen.

However, we did, you could argue, a simplification in the first analysis, because you see there’s another way that we humans take out nitrogen from the atmosphere, which is by cultivating nitrogen-fixating crops. So, we have also biological fixation nitrogen actively induced by us humans in modern agriculture. Now we have included that, so now we have a boundary that includes both the industrial uptake of nitrogen from the atmosphere in the industrial production of fertilizers, and the additional human-induced nitrogen fixation by, for example, legumes in modern agriculture. And together that forms a much more robust boundary, which ends up being an estimated 44 million tons of nitrogen as a maximum boundary per year.

I won’t go through the rest of the boundaries. I really urge you to look at the analysis and the materials that come with this lecture. But I really want to close by emphasizing that every boundary has an uncertainty range. And the uncertainty range is often quite large. It’s the humble reminder that science continuously adds new knowledge, and that the boundary position is proposed at the lower, more precautious end of that uncertainty range, because we now, as for ozone, that we always are facing surprise when it comes to the large changes we’re seeing in the Anthropocene.

Overall it’s also important to recognize that even though we have attempted to quantify boundaries for the nine boundary processes at the global level, they do operate across scales, and they do interact across scales.  We’ve done some very significant updates in terms of downscaling those boundaries that are relevant to downscale, and these include, for example, the coupling of a global boundary, on fresh water with the river basin definition of minimum amounts of environmental water flows.568

The coupling of the phosphorus boundary for fresh water, with a maximum amount of phosphorus per hectare of land that we can allow ourselves to apply. Same for nitrogen, taking it down to the hectare level.

These are really exciting developments which enable the planetary boundary concept to be operational also at the local level, for a business, of a community, or of a nation’s policies in terms of how to contribute to stay within a safe operating space. And that is in my mind one of the biggest advancements in the work we’ve done in the planetary boundary analysis over the past five years.

Antropoceno XXVI – A fronteira do ciclo do Fósforo e do Nitrógeneo

Interference with global n and p cycles

I’m going to talk with you about human impacts on the global nitrogen and phosphorus cycles.

The global biogeochemical cycles link the living and the non-living parts of the Earth system. Chemical relationships control the general patterns of interaction between geological and biological processes. It’s the way that the nutrient elements flow through land, ocean and atmosphere that ultimately regulate all of life on the planet. And human activities are changing all of these basic cycles.531

As we explore this topic, I’ll make reference to very simplified diagrams like this one, that show the present day cycles and the human changes. The arrows just show the overall annual flows of the elements between the Earth’s crust, atmosphere, oceans and the biosphere, that is all the living organisms on Earth.

It’s important to keep in mind that these flows are the result of many different Earth system processes, and at the same time it’s also important to remember that in the boxes, atmosphere, ocean, biosphere, and so on, we see many processes and feedbacks happening all the time. The Earth system is a very dynamic system, and the simple diagram is a very simple representation.539

Because all of these boxes are connected to each other through these different processes, human activities in one will play out in all of the others. It’s these consequences that mean that we need a planetary boundary for nutrient elements.

Piecing together the global budgets, in other words putting the numbers on the up and down arrows in those diagrams, is one of the major achievements of the last 50 years. It takes international and interdisciplinary research, and it involves scientists working in all kinds of environments around the world.538a

People are most familiar with the global carbon cycle because changes in carbon are so tightly linked to the climate system. The figure shows some of the processes that are happening at the moment. And here is the first of the simple flow diagrams I talked about.

The numbers show the annual flows between the different stocks of carbon in the Earth system, and the red arrow shows the human disturbance. Every year the biggest single change that we make to the carbon cycle is that we’re moving carbon from underground fossil fuel stocks into the atmosphere.538

We also contribute carbon dioxide into the atmosphere through deforestation and agriculture. But our main concern is that this carbon dioxide is accumulating in the atmosphere where it acts as a greenhouse gas. Climate is changing as the concentration increases.

But carbon isn’t the only element that we’re changing. People are much less familiar with the other elemental cycles, but they’re just as important, and actually they’re tightly linked to carbon and the climate system too.537

In this picture you can see the main changes in the nitrogen cycle. Nitrogen is one of the essential elements that sustains all of life on Earth. We use it in our proteins that make up our muscles, for example. The flow diagram shows the natural changes in white and the red arrows show the major changes that humans are causing in the system. The biggest change is the transformation of atmospheric nitrogen into reactive forms, like nitrate and ammonia. We do this because we need that nitrogen as fertilizer for the food production.

We also fix nitrogen from the atmosphere through many other processes, industrial processes and transport as well.536

Right now the red arrow of nitrogen fixation is bigger than the natural arrow of natural biogenic fixation of nitrogen. We are currently more than doubling the natural rate of drawing down of nitrogen from the atmosphere into the biosphere, but you can see that that isn’t all that we’re doing. This nitrogen is not all taken up by crops. A large amount is being released back into the atmosphere where it causes air 535pollution problems and acid rain, and is a climate greenhouse gas, and the rest is released into rivers and oceans where we have problems of nitrogen enrichment and eutrophication. I’ll explain what that is in a little while.

This is happening all around the world. When rivers, lakes, and coastal zones have very high concentrations of nitrogen, and other nutrient elements, the most responsive organisms draw up this nutrient most quickly. We end up with algal blooms, microorganisms are thriving in these water conditions.534

The image shows areas where there are very large amounts of marine algae, reflecting the highest concentrations of nutrient elements.

In the nitrogen cycle we have another particular challenge, which is that a large amount of the nitrogen is transported all around the world, very large distances, in the atmosphere. We see biogeochemical and ecological tipping points in area far away from the most intense sources. The densely populated areas have the most intense nitrogen pollution problems, but you can see from the figure that in this century of industrial activity, nitrogen really has become a global problem.533

The issue is not just a regional one. And nitrogen is not the only element that’s causing us concern at the moment. The phosphorus cycle is also being changed very substantially by human activity, and phosphorus is another one of these essential nutrient elements.

The figure again shows the processes that are happening in the Earth system, and the simple diagram shows the natural flows in white and the major human perturbation in red. Unlike nitrogen and carbon, phosphorus isn’t really affecting the atmosphere. The biggest change is that human activities are mining it from the ground and applying it to land surfaces for agriculture, 25 million tons a year. But a large amount of this phosphorus is being mobilized in the Earth system through the watercourses. It goes into our rivers and receiving oceans. It also 532contributes to nutrient enrichment. Nutrient enrichment doesn’t really sound like a problem, but it is a very serious one. Locally it’s a major problem for public health and environment, and it’s an economic issue as well.

In nutrient-enriched water systems biodiversity typically decreases. And when the algal blooms die and rot away they starve the water of oxygen. We end up with dead zones, and this is another example of tipping points that we see in the environment. It’s the risk of large and irreversible dead zones in the oceans that really calls for a planetary boundary for phosphorus.

The changes in both the nitrogen and phosphorus cycles are largely driven by the same human activity. In other words, fertilizer application for food production. The global impact arises from regional activities, so a really major area for research and policy at the moment is to improve the global assessment of both these nutrient elements.

The planetary boundaries for human interference in the global nutrient cycles now reflect these regional differences. The ecological impacts of the eutrophication of surface waters, and increasingly we’re working on trying to improve the links between the elemental cycles because they’re linked in nature.531


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.

The Antropocebne III – The Quadruple Squeeze

130aIn this lecture I’d just like to lay out to you what are the driving forces that explain why we’ve ended up in this new juncture with rising global environmental risks.

And it arises from what I’ve called a planetary squeeze, originating from four different large driving forces, the so-called quadruple squeeze from the world on planet Earth.

This squeeze arises from four different areas. And the first one is clearly population pressure. And population pressure is not about just the numbers, but it’s worth laying them out. We were three billion people at the point where we started the great acceleration of human pressures on the planet in the mid-1950s. We’re today seven billion people and we’re on our way, in fact committed, to nine billion people in only less than forty years, by 2050. But you see that absolute main driving force which is coupled to human population is not about numbers, it’s about affluence, it’s about what we call the 2080 dilemma, that the bulk of the global environmental problems that we face today are caused by the rich minority that stepped onto the Industrial Revolution in the mid-18th century. And the vast majority of co-citizens on Earth, the poor co-citizens in our world, have actually contributed very little to the damage and degradation we see so far.

But we’ve just now come to juncture, which is absolutely unique. It is now we’re starting to see the positive opportunity of eradicating poverty in the world, of eradicating hunger in the world, of having the majority, in fact the projection shows that we are moving from a world with 1.52 billion middle income citizens in the world to a world with 4, 5, 6 billion people with an average income equivalent to the developed nations in the world.

This is enormously positive, it’s an enormous opportunity, it’s even a right to development, but of course poses enormous challenges if we continue on an unsustainable route.

The second pressure is the one that we almost always focus on when we talk about global environmental change, namely human-caused climate change. Here we also have a dilemma related to three numbers.

The first one is 450 ppm, the concentration of greenhouse gases that normally is translated from science as the point beyond which we risk very damaging and even dangerous temperature rise.

The dilemma is that we have reached 450 ppm. 2014 is the year when we reach 450 ppm for all greenhouse gases. We are already in a danger zone. In fact science shows that we should try to stabilize at 400 ppm or below, meaning, to put it a bit bluntly, that even if we shut down the world today we are in a danger zone, and all projections show that emissions of greenhouse gases continue to rise in the world.

And the dilemma is that the pathway we’re heading is toward 560 ppm and beyond, which is a level way beyond anything that science stipulates as safe.

So this is the climate pressure. And you would have wished that this in fact, the largest ever environmental experiment to be performed on planet Earth, human-caused destabilization of the energy system in the atmosphere, would occur on a resilient and strong planet, you would have wished to have a strong, experimental object when you punch the system so hard as were doing when we are emitting greenhouse gases.

But unfortunately we now know from science that over the last fifty years we have undermined the ability of the Earth system to cope with climate change faster than ever before. The United Nations Millennium Ecosystem Assessment, the first global health control of the world’s ecosystems, show very clearly that over the past fifty years we’ve lost approximately 60% of the ecosystem functions and services that not only support human well being directly, but also which regulate the capacity of the Earth system to buffer, for example, climate change. One of them being, for example, the carbon sinks in ecosystems and oceans that we’ll come back to throughout the course.

But this is not enough. Not only do we have a climate crisis and an ecosystem crisis, the space within which we can operate safely is reduced by the insights that we can no longer exclude abrupt, sudden changes, what we’ll be calling “tipping points” or “thresholds.” And these tipping points and thresholds mean that the space, in terms of how many resources we can utilize on Earth, reduces very drastically. And it arises from the insight that we’ve always assumed that we can predict changes in the Earth system, such as in the oceans, and in forests, and lakes, and ecosystems in a predictable way, and that things change slowly and linearly.

But science now shows that that is the exception. The rule is surprise, very long periods of in fact very limited change, because systems have an in-built resilience to deal with change, just like you can see a boxer in a boxing competition getting one punch after the other and still standing. But then suddenly comes that final punch which means a knockout. Exactly the same type of abrupt knockouts is what we’re seeing in the biosphere.

And these are the four driving forces that changes the situation for humanity on Earth, that our precious Earth system is subject to a population, climate change, ecosystem, and the insights of surprise, which reduces the space for human development on Earth.

Now what are some of the examples behind this evidence?

Well the first one is on affluence. And this is data from the OECD showing the quite dramatic projections until 2050, where we’ll be nine billion people, shown here on the x-axis, and the green big area here shows the projected economic growth for the world. Can you imagine?

The world is projected to have a three times larger world economy in just 2050. The reason for this is predominantly shown in the red and yellow boxes, which shows the very positive trajectories for the world’s developing nations. Almost 500% GDP growth over the next thirty years. This is the affluence driving force.

The climate driving force is very well articulated in the latest scientific update from the United Nations Intergovernmental Panel on Climate Change. Here are just some key findings.

On the left-hand side you see the very dramatic scenarios to the future, which takes us all the way to the end of this century, and the possible trajectories in terms of the temperature rise. The red curve, the curve which we certainly do not want to end up with, is the curve that on average takes us to 4 degree C warming, a place where we haven’t been for the past four million years. The blue curve is if we would be able to bend the emission of greenhouse gases over the next 5-10 years and take us to a safe future below two degrees warming. But look at the black dots on this graph, and I really recommend you to study this graph particularly, if you have a chance. The black dots are observations. We’re following the disastrous 4 degree C pathway. So this is why we have such a large squeeze on climate.

On ecosystems, I’m just taking one example here, we’ll come back to this, which is showing the risks of deforestation. We’re learning more and more for rainforests, and this is an example from the Amazon rainforest, that if we cut down large tracts of rainforest, that combined with climate change, means that we dry out the entire system. And that is very dangerous for rainforests because the majority of the rain in rainforests is self-generated. You need a very, very large canopy of trees, which evaporate water, self-generates rainfall. But when you open up these systems they self-dry and can cross the tipping point and become savannahs.

So this is an example of the risks we take because this undermines freshwater supply to big cities, it undermines the ability to produce food, and therefore is an enormous risk with regards to livelihoods. It also makes us lose one of the large global carbon sinks.

And finally the risk of tipping points, which is moving from this example of a beautiful biodiverse marine coral reef system, supplying livelihoods for hundreds of millions of people in coastal regions worldwide, which we know today can abruptly shift over and become dead zones. For example, triggered by long, long periods of overfishing, eutrophication, sediments from agriculture, global warming, the system loses resilience slowly but surely, becomes vulnerable, but then a trigger, such as a linear event means that the whole system due to bleaching topples over and becomes permanently locked in a desertified state.

We’ll come back to the following graph which is a very dramatic piece of research showing that if we continue losing biodiversity at this pace by mid-century we can no longer exclude a global tipping point in terms of loss of genetic diversity on Earth. And if we lose that biodiversity we would lose the basis for human development and world prosperity as we know it.

So this is just some of the flavors of the science, why we can today say we are subjecting our own Earth, the basis for our own world development, to a quadruple squeeze of population affluence, climate, ecosystem crisis, and the understanding that we can no longer exclude abrupt tipping points that can lead to sudden changes that permanently puts us in a very undesired situation.

This is the challenge we’re facing, and this is what we need to navigate if we are really thinking about future generations.

O Fim do Mundo Antigo e o Princípio da Idade Média


De Ferdinand Lot, “O Fim do Mundo Antigo e o Princípio da Idade Média”, publicado em 1927, em França, republicano nos anos 50 e publicado em Portugal em 1980 pela Edições 70, é um tijolo de 980 páginas, que constituía uma leitura obrigatória para a licenciatura em História que na época fazia.

De notar o desfasamento de tempo entre a publicação em França e em Portugal, o que revelava bem o atraso que então se vivia entre o pensamento histórico europeu, sobretudo a renovação pela escola francesa,  e o pensamento histórico em Portugal.

O livro caiu-me na mão, depois de ter estado a vasculhar numa prateleira por textos sobre o Algarve, a ainda tinha dentro a ficha de leitura, que em boa hora o Hamilton Santos ensinava a fazer. Foi um hábito que fui mais ou menos mantendo, mas em cadernos do que em fichas da papelaria da moda.

Vem isto a colação pois nessa fichas resumia a questão essencial do livro. O problema da transição. Um dos problemas da história, na delimitação do se objeto de análise, tem a ver com a questão da categorização do tempo. A oitocentista divisão em idades (pré-história, idades antiga, média, moderna e contemporânea,), que em certa medida tem por base a teoria das três idades de Santo Agostinho (memória,intenção e espera ou pretérito, presente e futuro), é aqui questionada numa proposta de análise da “transição” ou seja um momento intermédio entre um mundo (uma cosmovisão, uma organização económica e social) vekho e algo de novo que emerge, ainda sem contornos precisos. Propões-se a que a história, como disciplina que estuda o tempo, caracterizando o passado e o que lhe sucedeu, deveria estar em condições de entender os processos que levaram a essa transformação. No fundo a questão da mudança, que é um problema que surge no século XIX, é explicar o que muda e porque muda.

Diz-nos  Ferdinan Lot que nessa altura, as análise que procuravam explicar a mudança , em termos pedagógicos (o século XIX é o século da emergência do ensino da história) não dispunha de bases para entende a mudança. Porque é que as transformações marcantes ocorreram, porque é que no campo da mentalidade, o mundo antigo deixou de explicar o mundo e emerge esse mundo a que chamamos medieval na Europa. . Recorde-se que é um tempo em que a Europa se fecha sobre si mesma, abandona as cidades e procura construir a Cidade de Deus.

A inovação do trabalho do autor neste livro foi o de ter ido resgatar testemunhos indirectos desse tempo. Começa por abordar a questão da crise política do século III. A perda de legitimidade do Imperador. O poder do Imperador era um poder essencialmente militar. O poder é algo que é delegado pelos militares que influenciam a eleição do Imperador. As legiões romanas, por volta do século III acabam por se acantonar nas regiões da Europa. São as legiões de delimitam as fronteiras do Império e o Imperador é o seu chefe simbólico.

No século III, a Oriente, os Persas ganham hegemonia sobre Constantinopla, e expandem uma nova religião que se confronta com a religião grego-latina. As legiões do Oriente deixa progressivamente de reconhecer a autoridade do Imperador e passam a submeter-se a quem mais paga. Apoiam quem lhes acena com mais benefícios. A conversão ao cristianismo por Constantino, a liberdade religiosa e a transferência da capital do Império para Bizâncio tem efeitos permanentes. A separação do Império e a tentativa de recomposição do poder político tem um efeito fugaz e não atenua a crise religiosa. A transformação da religião católica como religião dominante vai influir na organização do Estado e marcar a predomínio da malha paroquial. Assiste-se a uma regressão do mundo romano, a uma emergência de sistemas de troca direta e em géneros. A linha dorssal do comercio entre as regiões do Império entra em decadência.  O mundo torna-se mais fechado. Leituras que hoje são interessante para pensarmos a Transição entre o velho mundo que conhecemos e o novo mundo que emerge na Fronteira.

Escrita Ibérica e cultura arraiana



A Propósito de escrita íbérica surgem ao longo da área raiana diferentes alfabetos que foram usados pelas populações peninsulares antes da romanização. Inscritos em estelas e outros monumentos líticos, dão origem a uma variedade de aproximações. assim podemos encontrar A escrita levantina, a cóniga e a tartessica, a hispânica meridional ou lusitana.

Ha na sua organização algum caos que termos que ordenar.

  • Silabário de Espança
  • Escrita do sudoeste (ou tartésica ou lusitana meridional)
  • Alfabeto greco-ibérico
  • Escrita ibérica sudeste (ou meridional)
  • Escrita ibérica noroeste (ou levantina)
    • Variante dual
    • Variante não-dual
  • Escrita celtibérica
    • Variante oriental
    • Variante ocidental