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- [Narrator] We're talking about why biodiversity is important specifically to us as humans in the form of ecosystem services. Given that we'll lose about 20% of the present species richness by the middle of the century it's crucial to ask why that should matter to any of us. Should be worried about that loss? And why do so many of us care so much about it already. There are three main ways in which biodiversity is crucial to humans. The first is by direct services, the second is by indirect services, and the third is the aesthetic or ethical effect. We get so many things directly from biodiversity on this planet, food, clothing, housing, transportation, many medicines and medical supplies, and even energy in some cases. These things are derived directly from various ecosystems. Food goes without saying, all of our major food types, as diverse as they might be, originated in diverse ecosystems. Turns out, that they're a wild types of tomatoes still growing in Peru. These Peruvian tomatoes are a different species from the kind of tomato we typically eat and hold some of the genetic diversity within them. When bred with some of the tomatoes that we're using as our own food now, the yield from the hybrid tomatoes can go up almost as much as 50%. And, we wouldn't have that productivity if we'd let that wild type of Peruvian tomato go extinct. If we didn't have that as part of the biodiversity out there today, there's no way that we would have access to that genetic diversity. Another direct service provided by biodiversity is shelter. Originally, we built housing out of all kinds of biological materials and even today, we're still building houses out of trees. What about medicine? Almost all the medicines that humankind has developed have come directly from studying the way that organisms live in their environment, how they interact and the chemicals that they use during those interactions. The rosy periwinkle is a very famous example of a plant that grows in some very secluded environments in Madagascar. And it turns out that this plant produces a couple of very interesting chemicals that are now used to treat childhood leukemia. Again, we wouldn't have those medicines if the rosy periwinkle had gone extinct. Some of the more interesting things that I think people forget about when thinking about the value biodiversity fall under the category of indirect services that are delivered to us by healthy ecosystems. If you think about mangrove swamps which hare these fantastic places along the coastal margins of some tropical countries where specific types of trees, trees called mangroves grow. Mangroves can grow in salt water, so they form a semi-marine forest at the edge between land and sea. There are many species of mangrove trees and they're all really tough, resilient plants that provide tremendous services to us and to the natural environment. They protect the coastline from wave action and erosion, they're nurseries for all kinds of different types of organisms, and some of these are very important food types for us. Unfortunately, in certain parts of the world people are destroying the mangroves in order to make shrimp fisheries. They remove the mangroves and set up shrimp farms with the idea that they're adding economic value to that part of the coastline by putting in a shrimp farm that's going to produce a commercially viable product. But if you look at a graph of the value of these things then value of the shrimp farm is really only one third, maybe even only one quarter of the value of the original, undisturbed mangrove swamp because of the protection that the mangroves give against storms and erosion and the food sources they produce such as fish. You can actually attach a dollar value to these things which is sometimes the only way that people really come to grips with ecosystem value. It's the only way that people really understand the value of ecosystem services to humanity. Economic value of intact biodiversity has also been determined for ecosystems far from mangrove swamps, much closer to home. Some years ago, a large city on the east coast, which shall remain nameless, except that it's New York, had an issue with the quality of its source water. There are rivers feeding into the New York City area and the sources of that water were being compromised by pollution and environmental degradation to the point where biodiversity was being lost in some of those areas. So, city officials had a question in front of them, how do we deal in a cost effective way with this problem of declining quality of our water. It turns out that to build treatment plants to deal with cleaning the water up was gonna cost somewhere in the neighborhood of $6 billion just to build the treatment plants. Then another $300 million per year to maintain those plants and make sure that they were doing the things they were supposed to by removing the harmful chemicals that were being introduced through environmental degradation upstream. Then they looked at what it was gonna cost to clean up and restore the environments to make sure that the ecosystems and the biodiversity in those ecosystems were maintained to the point where they were doing what they would naturally do by removing chemicals from the water, basically filtering it through wetland habitat. Wetlands are tremendous, tremendous places for the recycling of dangerous chemicals and for the removal of chemicals from water and for clarifying and cleaning water. The cost for this restoration was gonna be about $1 billion, spread over 10 years. Much, much lower costs. So the answer was pretty clear, you're gonna go and spend that billion dollars over 10 years. Not only do you enhance the quality of the water in a very cost effective way but you do something else, too. And that addresses the third and final aspect of biodiversity value. The ethical and aesthetic services or value provided by biodiversity. These services may in fact be, in some ways, the most important ones. Sure, we can attach dollar values to the direct and indirect costs of a decline in biodiversity and the decline environmental services and ecosystem services but the ethical and aesthetic value is something that's very, very difficult to put a price on. You might say, okay, well, it costs so much to go visit a park or you might enjoy the views so much that you'll put a quarter into the telescope and soak in that environment but that's not really what we're talking about. The value here comes in what we leave for the future. A drop in biodiversity, removal of biodiversity, the extinction of species, those are things that we can't repair. Lost biodiversity is something we cannot bring back. So our children are gonna inherit a depleted world. The ethical and aesthetic quality of the environments that they're going to experience in their future, is gonna be decreased. How do you put a dollar value on that? We are the stewards of the environment but we are also the major influence on environmental quality and certainly on ecosystem function these days through our activities that result in pollution, over fishing, habitat destruction, loss of certain species from the environment. No one wants a world that's filled with nothing but wheat, corn, dandelions, some cows and us. That's a very simple ecosystem that's fraught with future difficulty and instability. If you reduce biodiversity to the point where the loss of species in the ecological food web causes an ecological collapse of that system, we won't be just standing by watching that collapse, we're going to be part of it. Clearly, biodiversity ecosystem are great places to live and to visit. There's much to see and make you feel happy, restful, appreciative, full of awe, reminded of what a remarkable and unique plant this is. After all, it's ours. I think there's a deeper sort of societal psychology at work here. And it behooves us to pay attention not just to the economically measured direct and indirect services and benefits provided by diversity rich, healthy ecosystems. But also to the ethical and aesthetic value of those amazing environments that are the inheritance we will leave for future generations.