I'm Jonathan Tomkin from University of Illinois. Environmentalism has actually been around for a long time, even Western countries. Medieval cities like fourteen Century Paris and London had rules against dumping animal carcasses within the city limit. And, of course, as we saw from the Tragedy of, Tragedy of the Commons solutions, local groups have been caring for local pastures and range lands for centuries. In industrialized countries, We've began to think a lot more about the global problems to do with the environment. And, not just the global problems, We actually have also began, begun to think about the environment as having it's own worth, in other words an intrinsic value. This is actually quite recent in industrial countries. It probably came about in the 1970's. There were movements all around the world including in non-Western countries like India, but we often associate this sort of movement as beginning in the West in places like San Francisco which held the first Earth Day in 1970. And, since then in the ensuing decades, environmentalism has become a very mainstream political way of thinking. Many organizations do a lot of green things that they didn't used to do in the 50s' and 60s'. And so there are green parties now and they often share power in parliaments and governments around the world. And, This agenda of environmentalism isn't just about those local issues which people cared about primarily in those earlier centuries. These issues are now about things like global warming, or about saving the rain forest, Or species that are not within the national borders. So, for example, whales, or polar bears, or pandas. What's interesting about this diversity of environmental thought is that it spread beyond political movements and social movements and even to the corporate world. Now, in some cases, this might be an example of what's known as green washing and that is sort of using environmental concerns as a PR. But, even there, you can see that's the impact of the green movement that has made caring about the environment a very mainstream thing to do. But, it looks like corporations are even going beyond that, right? They're not just doing it for the image, they really do want to streamline their services and create less waste, for example. So, given this background, we could hardly say environmental groups are triumphant. So, why aren't they celebrating? Why isn't there a big success? And I think the reason for that is environmental groups and individuals concerned about the environment actually don't see as much progress as they think as necessary for saving the planet and making it sustainable. So, why might environmental groups not feel that we've reached this sustainable state? How do we know? Well, in this lecture, I'm going to talk about sustainability metrics. And these are ways that we measure the environment to try and determine how sustainable a process is, or how much damage is being done. Now, we talked about this a little bit earlier when we described ecosystem services and the attempts to value that. And it turns out that, that becomes an important component in a lot of the ways the sustainability metrics try to estimate our progress towards sustainability. A lot of these metrics come out of this set of rules sometimes known as the Daly Rules, maybe not explicitly, but it's often the same set of thinking. And there's three sets of rules. The first rule talks about renewable resources must be harvested basically at a sustainable rate. And so, an example of that is that might be that fish or timber should be harvested at the rate that fish reproduce or that trees grow. Secondly, It's natural that we do use some non-renewable resources. So, right now we're using fossil fuels, And you might argue that some other resources, for example metals, or other mined things are in some sense limited as well. So, as we use those, the Daly Rule suggests that we must develop alternatives to replace them at the rate that they're being lost. So an example for that might be, is as we use up fossil fuels, we should be developing renewable energy sources. And finally, there's this idea that the amount pollution that we create should be matched by the environment's ability to assimilate it, that is absorb it. And a good example of that would might be carbon dioxide. Since industrialization, about half of the carbon dioxide emitted by human activities have actually been absorbed into the oceans and to the land. and in this way, the natural systems actually being overused, right? We can see that we're not matching the carbon, the ability of the natural environment to absorb the carbon dioxide that we are producing. So, we can produce some pollutants like carbon dioxide, but under the Daly Rules we can't produce more than the environment can absorb at once. Proponents of this way of thinking see these rules as foundational because in some ways they're physical limits, and they're sort of no way around them if you like. If we want to be sustainable for any period of time, we have to obey these rules. So, these rules are used generally explicitly in sustainability metrics but they're used as the foundation for the assumptions and the thinking that go into building these metrics. One very popular idea, and I know I've used this word myself a lot in this course, is the foot-printing idea. And so, we might think about an environmental footprint that somebody has on nature and there's lots of versions of this idea. There's the ecological footprint, a water footprint, energy footprint, and a carbon footprint, might be some of the ones that I've mentioned. Let's look at a couple of these in detail in particular, the ecological footprint. In the last lecture, we spoke about ecological services. Ecological footprint is a measure of our consumption of those ecological services. Now, if we consume more of those services than the land can support, then we could argue that we're in an unsustainable state. An ecological footprint can be assessed for an individual, a region, a country, or the whole planet. How do we calculate this? Well, firstly, We determine the consumption of particular ecosystem services by that individual, or nation, or organization. This includes things like food, housing, energy, transport, And things that require the use of the land. By using the ecosystem services idea then, we can see how much land is needed to provide each of those services. And so, it really is a footprint, insomuch that the measurement then, is a land area. How much land area does an individual, a country, or the whole nation need to provide the services that it's consuming. Clearly, this varies from region to region. Developed countries have ecological footprints of between three and five hectares per person with the United States ranking the highest. The world average is estimated to be around 2.2 while the in, ecological footprint of a developing country, like India, is thought to be about.4 hectares per person. So, in principle then, we can figure out whether or not the Earth is on a sustainable course by adding up all of these ecological footprints for every person. So, if you do this, you can estimate the total number of Earths we would need to provide the ecosystem services that we rely on. If we have more that one Earth, then we're in trouble because we're not using things sustainably. Estimates vary but one recent value suggested that we're using about 40% more land than is actually available on the Earth. So, in other words, we would need about 1-1/2 Earths to match our consumption patterns. This is clearly not sustainable. And. of course. you often hear things that if the all the world lived like the United States then we would need around seven Earths because the population of the United States is relatively small relative to the population of the planet but it's consumption rate is very high. There are some problems with this idea though and I'd like to talk about those. And these illustrate the difficulties of making a reliable sustainability metric. Firstly, it has a particular problem in that it is often used to compare different countries. This sort of inter country comparison is often unreliable and unfair. Let's think about some of the places that are actually more sustainable than others. In western countries, the most sustainable places are generally the cities. City dwellers use less resources, they have smaller apartments, they take public transport. So, in fact, the carbon emissions, for example, for someone living in the city is usually significantly less than somebody who lives in the suburb or a rural area. So, on that sense, we would say that the city dweller is in some ways maybe more sustainable. But, in an ecological footprinting analysis, they actually appear to be much less sustainable. That's because there's hardly any land in the city per person. And so, obviously comparing a city to the country as a whole might be a little bit unfair. Similarly, though, some countries are much urbanized and much denser. A good example of this might be comparing the United Kingdom and Australia. Australians are, in some measures, are as polluting as Americans. But, according to the ecological footprint idea, they're in the black because the country is so large relative to the small population. Meanwhile, the denizens of the United Kingdom, we've much more efficiently in terms of, say, energy use, they use about half as much energy per person. And yet, because the land mass is less, it looks like, according to the ecological footprint idea, that individuals there are behaving less sustainably. So, this idea doesn't take into account things like trade between regions or nations, Or the development of, for example, our new technologies. One of the things that's Why cities are so successful and thriving in the modern world is because of their fonts of innovation and the provide new services, new ideas, and these new ideas could help us live sustainably in the future. A second problem with ecological foot printing is it doesn't really know the difference between sustainable use of land and unsustainable use of land. It really just looks at the consumption of that ecosystem servers. And actually, this becomes the very important question is. it doesn't matter if we're using land as long as we're using it sustainably. But, it turns out that it's very difficult to measure. And, when you look at something at a regional scale or indeed a global scale, clearly, you don't have very much information about each piece of land, right? You're making some kind of aggregate average. So, so that makes it a very difficult measure to rely on in terms understanding are we truly being sustainable. What's more is that the way that the land is measured is very binary at time. It's being used for one thing, or, and nothing else. Whereas, in reality, land is often used for many different things at the same time. And if we do use land for many different things at the same time, then it's actually providing multiple ecosystem services. And so, perhaps the land is in a sense more productive than the ecological footprint idea would have us believe. Finally, I would point out that technological change is also missing from the ecological footprint. And if we refer back to the original Daly Rules, We know that we can replace non-renewable uses as we develop better technology. And, in an ecological footprint measurement, we don't collect that information. We don't know that solar cells are actually cheaper now and more efficient than they were ten years ago or twenty years ago, for example. So that there are some issues with the idea of using ecological footprint and relying on that. Produced by OCE, Atlas Digital Media at the University of Illinois Urbaba-Champaign.