In this video Paul Andersen explains how land is developed for human use. Urbanization has occurred through the last century as people have moved to cities in large numbers. Transportation and the arrival of the car have led to urban sprawl and urban blight. Smart growth can be used to mediate some of the ecosystem impacts. Land is also preserved in parks, refuges, and wilderness areas.
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Transcript Provided by YouTube:
00:03
Hi. It’s Mr. Andersen and this is environmental sciences video 18. It is on land use. You
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are probably familiar with this skyline. It is the Las Vegas strip. But it is actually
00:13
a small portion of the Las Vegas area. This picture was taken in 1984 and I am going to
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show you a picture taken in the same location in 2011and watch what has happened to Las
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Vegas. So we have had huge development into the periphery. We call that urban sprawl.
00:29
And it brings with it some ecosystem impacts. And so land development will always occur
00:33
with humans. But we are seeing a movement from the rural to the urban, into the cities.
00:38
We call that urbanization. That is actually a good thing. It can leave more land conserved
00:43
for ecosystem services. The problem is not only are we seeing growing cities but we are
00:47
seeing growing transportation. We are getting highways, the arrival of the car. And that
00:52
leads to urban sprawl. The cities are spreading out and we lose all of the benefits of the
00:57
city. Also as people move out they take their tax base with them and that can lead to urban
01:01
blight on the inside of the city. And so we are getting these ecosystem impacts. With
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urban sprawl we are eating up the land around the city. So there is a loss of land and also
01:10
we have pollution. So we can have air pollution. We can have light and noise pollution and
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heat pollution. We see that in the urban heat islands. But we are always going to have development.
01:19
So people are putting forward this idea of we need growth that is smart or smart growth,
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to avoid some of these negative consequences. But in parallel to that we are also trying
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to conserve land. And we have been doing this in all countries around the world. In the
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US this is highlighted in the national parks. We have wilderness areas, wildlife refuges.
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And then around cities we are trying to protect the wetlands and the forests. And so this
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is the movement towards the cities. In 1950, this is where people were living. 70 percent
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of the people on the planet lived in rural areas. And less than 30 percent in the cities.
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Watch what happened over the last 50 years and what they predict into the next 50 years.
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Those are going to flip-flop. And so we are getting this movement to the cities. This
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has already occurred in a lot of the developed countries. And so the US, it is already over
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75 percent of the people are living in the cities. But we are going to see this in developing
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countries. As they come online we are going to have more people moving into the urban
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areas. You can see this in an age structure diagram. This is females in a rural county
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in Iowa. And you can see that once they go to college the numbers drop off in that area.
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Now why is that? In a rural setting, with industrial agriculture there are not jobs
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anymore. And so you can see that they are moving into the cities. This is the growth
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in a urban area of Iowa. And so we are seeing this movement into the cities due to opportunity.
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You can get jobs there. And once you move into the city you are not going to move back.
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And so this transition is going to occur into the future. It is actually a good thing. If
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we think about low density housing, I want you to concentrate on the green area here,
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let’s say we have nine houses and they are all spread out. Let’s say this is in a subdivision.
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Each of them have their own yard. And we have to put roads to each of those, and what is
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happening is we are losing that valuable land. But if we get the movement into the city,
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so we take those same nine houses, stack them on top of each other, let’s call them apartments,
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now we have higher density housing. We can have a park that they share and fewer roads,
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and now we leave more of that land outside the city. And so cities are actually good.
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The problem is urban sprawl. And so if we put a city right here and then put a couple
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of roads to it, so back around the turn of the last century, cities started to grow.
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And that is because there were opportunities there. And so if we say this is the housing
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density, so we are going to have the greatest density inside the center of the city, there
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are opportunities there. It is really hard to get into the city. We do not have a lot
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of roads. We do not have a lot of transportation. It is hard to get out of the city. And so
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we are going to see these flourishing inner cities. Now what happens though, around the
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last half of the last century, is that we have the arrival of roads, infrastructure
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and the automobile. Now it is easier to get in and out of the city. And people started
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doing that. They started buying up lower density housing. And so what you get is this urban
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sprawl. This movement away from the city. And this is a positive feedback loop. The
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more people move out, the more roads there are the more tax base there is and we are
04:18
going to get more movement out. And we are going to encroach into the area around it.
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They are also brining their tax base with them. And so that leaves, a lot of the time
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urban blight, areas on the inside of the city where people are not actually living. Now
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this is kind of a United States problem or it is more of a problem in the US. And so
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if we look at this graph, this is the area per person. And so these are all US cities.
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And so in US cities like Houston and Phoenix we have low density housing. If we look on
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this side, on gasoline use in the US we are going to be using more gasoline. And so since
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cities in the US formed later than those in Europe, and also since we were using the automobile
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and we had increase in highway structure, we have had this sprawl be a larger problem
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in the US. It brings with it problems. In all cities pollution would an example. This
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is smog in Mexico City. We also get noise and light pollution and heat pollution. If
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we look specifically at heat pollution we are seeing these heat islands where cities
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are. And so this is a picture of Manhattan. This is Central Park right here. And then
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we are looking at a map down on Manhattan. You can see Central Park right here. And areas
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that are really green are areas that are rich in vegetation. But watch what happens if I
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now show you heat coming off of the land. You can see that we are going to have higher
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temperature, hotter temperatures where we do not have that vegetation. So as we build
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up those cities, it is actually absorbing that heat and creating a heat island. And
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so how do we solve this problem? Well one thing would be to plant a lot of trees. But
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how do we return people to the city center? A lot of people are going around this idea
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of smart growth. And so we need to create desirable locations in the downtown, walkable
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neighborhoods, compact building design, sense of place in the city, growth boundaries perhaps
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around the city so we force people to stay within those settings. Now there are pros
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and cons of all of these, but sprawl is definitely having some negative impacts. Now outside
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the cities we have also have been trying to preserve land. So the National Park Service
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was instituted and we have National Parks like Yosemite and Yellowstone National Park.
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We try to protect this area for people into the future. Now if you have ever been into
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a park we still have roads there. We still have infrastructure run by the National Park
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Service. We also have wildlife refuges. So those are administered by the US Fish and
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Wildlife. So this is ANWR. This is in Alaska. It is a national wildlife refuge. These are
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set up to protect specific species. In this case it is the caribou. And then the strictest
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of constraints are in the wilderness areas, which are administered by all four of these
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entities. Inside a wilderness area we try to limit roads. The only way you can really
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get in is walking, riding a horse or by canoe. And so we do not have mining inside those
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wilderness areas. And so we are trying to protect these areas so they are not developed
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into the future. And we are also, on a micro scale, trying to protect wetlands around cities.
07:09
This is a forest that has been protected in Poland since the 1300s. So if we put boundaries
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around that we can number one mitigate it. So we do not have development into these valuable
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areas. We can restore them when they are damaged or remediate them. All of these are very big
07:25
things that we can do around cities. And so did you learn the following? Could you pause
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the video at this point and fill in the blanks? Remember development and urbanization can
07:33
cause urban sprawl. That pollution could be air pollution, light pollution and heat pollution.
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We are trying to conserve our planet, preserving it in national parks, wilderness areas, wildlife
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refuges and wetland areas. But the biggest thing is we have to be smart in the growth.
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We are always going to have development, but we have to make that smart development.
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And I hope that was helpful.
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This post was previously published on YouTube.