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Monday, May 27, 2013

Efficiencies of Cities

In The Conundrum: How scientific innovation, increased efficiency and good intentions can make our energy and climate problems worse,  David Owen gives us the bottom line on living more sustainably: "We need to live smaller, live closer, and drive less."  This is exactly how people live in the most resource efficient communities in the US - Manhattan, Chicago, San Francisco, and other dense urban areas.

Advantage: City

Yes, while cities as a whole consume vast amounts of resources, on a per-person basis cities are the most resource-efficient paces to live.  Here are a few reasons why:
  • Housing density
    • Living space is smaller, which results in a lower need for heating, cooling, lighting, and stuff to fill the space.  (See note 1 below to explore this in Footprint USA)
    • Use of land is much more efficient, because living spaces are stacked up in tall buildings
    • By sharing walls, floors and/or ceilings, living spaces are connected to more spaces at the same temperature, making for further increases in heating and cooling efficiency
    • Without back yards and their attendant grass and pools, there is much less water use per household.
    • Many people do not have cars, which means they don't need garages. Or parking spaces. And they don't need to buy, ensure, maintain or fuel cars.
  • Traveling less
    • When cities integrate living, working and retail spaces, people can walk more often to their destination.
    • When trips are too far for walking, the density of travelers and destinations makes public transportation practical.  
    • Public transport, when fully utilized, is much more resource efficient than personal vehicles
    • Even when not more efficient that personal vehicles, the shorter trips made by public transport within cities still save resources over personal vehicles traveling longer distances fro suburbs to commercial areas
Cities also improve quality of life in a number of ways
  • Provide access to high quality health care, education, and entertainment
  • Housing mobility:  More people rent than own, which makes it much easier for someone to choose to move to take advantage of new opportunities
  • Job mobility: With a higher density of companies in a small area, there is more interaction between people in different companies and industries. 


At the same time, cities provide some challenges that need to be addressed to draw more people to them:
  • Expensive housing:  This is a big challenge that can only be met with increases in the supply of housing.  One way to achieve this is to convert primarily business zones into more mixed use.  Mixed use areas, where people have a reason to stay in the area other than for work, provide many other advantages cogently described in Jane Jacobs' classic work Death and Life of American Cities, published more than 50 years ago.
  • Lack of green space: Urban areas like San Francisco, Manhattan, and Chicago have large green spaces and waterfronts that give people a place to play and enjoy nature.  It is also possible to build more green spaces into our structures, as in the re-imagination of Chicago's Marina City Towers, below (source):   

  • Potential for higher crime:  Many cities have high crime areas.  Jacobs makes a case for mixed use urban areas, where people are on the street, or looking down at it, at all times of day, rather than just 9 to 5.  Also, when people live in an area, they are more likely to get to know each other, making it harder for anonymous transient criminals to prey on the public.  
  • Manufacturing and agriculture not nearby:
    • Manufacturing is a relatively small employment sector, as most manufacturing is done overseas, and the production in the US tends to be geographically isolated. Thus manufactured items need to be transported long distances no matter where people live.  If people live more densely, then there are fewer destination points for manufactured items, which makes their transport more efficient. 
    • With regards to agriculture, vertical farms, described in The Vertical Farm: Feeding the World in the 21st Century by Dickson Despommier, are a compelling way to bring food production near to population centers, provided that plentiful renewable energy is available.

The Bottom Line

As we begin to feel the effects of having only one planet to share, living small, closer, and driving less will be a requirement.  The only alternative is for a lot fewer people to be inhabiting the earth.

Note 1: Exploring housing density in Footprint USA

  1. In the Visualization menu, select Selection Summary
  2. In the Data menu, select Population -> Number of Rooms -> All
  3. Select County in the Visualization menu
  4. Zoom in on the New York City area (by Long Island)Tap on the tall skinny county, New York County.
  5. Scroll down in the Selection Summary view to the Homes section,  Number of Rooms subsection.  You should see view similar to that shown below:
  6. Copy the selected data.  If you have Numbers installed, paste it into a spreadsheet.

  1. Go back to footprint and select another county - I choose Putnam, the light colored roughly rectangular county above New York County.
  2. Copy the same data, paste it into the spreadsheet next to the first set, label the columns and generate a bar chart.   Here's what I got:
In this chart you can clearly see that the majority of houses (or apartments) in New York county are 3 or 4 rooms, while in Putnam county the majority of homes 5 rooms or larger.

How do these counties compare in terms of Travel Time to Work?  How about Water use Per Person?  What do these statistics look like for the county in which you live?

Tuesday, May 7, 2013

One-Planet Living

Each year the Worldwatch Institute publishes a State of the World, which is a collection of articles by different authors. This year's version, State of the World 2013: Is Sustainability Still Possible?, has some fascinating and enlightening articles. This is a first in a series of blog posts relating ways in which you can use Footprint USA to further explore some of the ideas discussed in the State of the World.


The chapter "Getting to One Planet Living", by Jennie Moore and William E. Rees, discusses the limits of available resources created by the fact that all seven billion of us share one planet. This is captured in the concept of an "Ecological Footprint" which is defined as:
"The productive ecosystem area required, on a continuous basis [by the] population to produce the renewable resources it consumes and assimilate its … wastes.  There are only 11.9 billion hectares of productive ecosystem area on the planet.  If this area were distributed equally among the 7 billion people on Earth today, each person would be allocated just 1.7 global hectares (gha) [4.2 global acres] per capita.
In 1961, humanity's ecological footprint was about two thirds of global biocapacity; today humanity [requires] 1.5 planets… [This] cannot continue indefinitely; ultimately, productive ecosystems will become depleted.  Global productivity is further at risk because of potential climate change, ocean acidification, and other consequences of the buildup of CO2 in the atmosphere."
This chapter goes on to introduce the concept of a "fair Earth share" of global biocapacity - that amount of resources that 1.7 gha can provide.  The authors then compiled, from a variety of sources (Footnote 1), what a fair Earth share can provide, and compared it to what is actually being used, as well as to what the highest consumption societies are using (Footnote 2):

Metric One-Earth Living Current Global Average Three-Earth Living
Daily calorie supply
Meat consumption (kg/year)
Living space (square meters)
People per household
Home energy use in GJoules/year
Motor vehicle ownership
Motor vehicle travel (km/year)
Air travel (km/year)
CO2 emissions (tons per year)
Life expectancy (years)

Exploring Fair Earth Share in Footprint USA

We can use Footprint USA to explore some of the aspects in the above table for life in the US - daily calorie supply, meat consumption, home energy use, motor vehicle travel and CO2 emissions - and what it would take for us to get to one-planet living, where we use only our fair Earth share.

Daily Calorie and Meat Consumption
In the navigation menu of Footprint USA, select "Food".  This does not show calories, but it does show  how much food is wasted in the US (Footnote 3).  From this diagram we can see that, in the case of vegetables, fruits ,and nuts, more are wasted than are eaten.  The primary waste comes at the point of consumption (at home and in restaurants). 

The good news here is that you can control this as an individual. End-consumption waste is about 20% of all food grown in the US.  Without this waste, our 3383 calories would go down to 2899 calories.  It would take eliminating all waste to get down to one-plant living.  That's obviously not feasible, but notice something else in this chart: how much food goes to feed the animals we eat.  This is approximately equivalent to the amount of food wasted.

Livestock consume calories from plants that we could otherwise eat.  Let's drill down into this a bit.  Select "Selection Summary" from the Visualization Menu, and you'll see a summary on the left side of the screen of how much food is eaten per person per year.  In 2009, 191 pounds per person of meat and seafood were eaten.  That's a half-pound of meat per day (averaged across everyone, including vegetarians, babies, etc.).  If everyone who ate meat cut their meat consumption in half, we'd save as much food as cutting out all end-consumption waste.  If we do both, then we can reach one planet living for calorie supply.  

However, we're currently living 5 planets per year of meat consumption, so cutting meat consumption in half won't get us to one-plant living in this dimension.  It is unlikely that we would be willing, as a society, to eat one-fifth the amount of meat we eat today.

Besides using agricultural land, why do we care so much about meat consumption?   One issue is greenhouse gasses.  Livestock produce methane as they digest their food.  To get a sense of the impact of this, select "Atmosphere" from the Navigation menu.  Note that Methane is listed in the flow diagram as "Methane 25X".  This is because methane has 25 times the greenhouse gas warming effect of the equivalent amount of CO2.  Now, tap on the "Methane" box on the right of the flow chart.  You'll see all the sources of methane, and you'll also see that Agriculture is the single largest source.  Agricultural contributions come from more than just livestock, but livestock is the largest source.

So, if we want to continue to eat more than our fair-Earth share of meat, we'll need to find other ways to cut greenhouse gasses.  More on this later.

Home Energy Use
One-planet living requires a home energy use of 8.4 gigaJoules per year, which is 6.4 kilowatt hours (kWh) per day.  How are we doing in comparison?  In Footprint USA, select "Footprint" from the Navigation menu.  For the entire US, household energy use is 83 kWh per day.  However, the majority of this is transportation.  You can see this by selecting "Legend" from the Visualization menu, and then tapping on the "Energy Use" pie chart.  You'll see what is shown in the image below, illustrating that non-transportation home energy use is approximately one-third of the total, about 28kWh per person per day; 4.3 times the one-planet value.

Can we reduce our non-transportation energy use by a factor of 4?  Yes, it is feasible.  Select "Energy" from the Navigation menu, and you'll see the diagram shown below, indicating where energy is going.

Some ways can we reduce household (residential) energy usage:
  • Conversion loss: Energy is lost converting heat into electricity, and transmitting the electricity from the point of generation to the point of consumption.  The majority of this loss is conversion.  Were we to switch to solar and wind, this conversion loss - an amount equal to about half of the residential, commercial and industrial electricity use - would disappear.  This takes us from 28 kWh to about 18.5KWh.
  • Heating and lighting: There is a building efficiency standard called Passive House, which results in ultra-low energy buildings.  It uses between 75% and 95% less energy for heating and cooling.  Homes can limit energy spent on lighting by using skylights to harness sunlight for daytime indoor lighting, and LED lighting at night, which uses  75% less energy than incandescent lighting.  The combined decrease in heating, cooling, and lighting energy use easily reduced household energy use by two thirds.  This decreases the 18.5 kWh number to 6.1 kWh.
With solar and wind power and efficient heating, cooling, and lighting, we can reach the one-planet goal for household energy use without sacrificing our quality of life. This calculation does not count the energy required to build all the wind and solar electricity generation capacity.  It also does not count the energy required to rebuild or retrofit all the homes in the US.  How to think about the impact of that transition is left to a future article in this blog.

Motor Vehicle Travel
The greatest challenge to achieving one-planet living in the US is how much we travel.  The fair Earth share is 582 km (361 miles) of motor vehicle travel per person.  Where are we in comparison?

In Footprint USA, select "Transportation" from the Navigation menu.  In the Visualization menu, be sure that "Selection Summary" is checked.  On the left side of the screen (with your tablet in landscape mode) you will see "Travel Details".  Scrolling down a bit, you will see "Person Miles per Year by Vehicle Type."  Adding all the personal vehicles together (car, van, SUV, pickup truck, other truck, RV, motor cycle and light electric vehicle), we get 10,679 miles per person, almost 30 times higher than our fair Earth share.  Is it posible to get close to the fair share?

One thought is to use public transportation.  This is only practical when we live close together.  For example, Let's take a look at New York State, home to the densest city in the US.
  1. Select "Geographic Map" from the Navigation menu.  
  2. In the Data menu, navigate back to the top.  From there, select "Travel", "Trips by Purpose, then "All".  (You should see a single pie chart over the US.  If you don't, then go to the Visualization menu and select "US"
  3. Tap on New York State.  The pie chart and information in the Selection Summary will change to   reflect that of New York State.
Adding personal vehicles together, we get 7,000 miles, about a 45% reduction from the US average but still 19 times too high.  If everyone carpooled, we might cut that in half again, to 3,500 miles per person, still almost ten times our fair share.  Taking half as many trips gets us down to 5x our fair share.  The only way we would have any chance would be if we lived in a dense city.   It would be great if we could zoom in on New York City and see what the miles per person looks like there - unfortunately, this data is not presently available at the city level.

Footprint USA does have information at the city level for public transit ridership.  Let's take a look.
  1. Navigate up one level in the Data menu, then select "City Transit Ridership".  Select "All"
  2. Zoom in on New York state.  Once it is filling most of the screen, select "City" from the Visualization menu.
  3. Tap on the dark green shape that is New York City.
  4. Scroll down to the the bottom of the summary view on the left, to the section marked "Public Transit Ridership".  You will see something like this:

Here you can see that the average New York City resident takes 402 trips per year on public transit - more than one a day.  While we unfortunately don't have the data available to see if that gets us to the fair-share level of travel, it provides strong evidence that living in high-density urban environments is a key part of the solution.

CO2 emissions
The global fair Earth share for CO2 emissions is 2 tons per year.  To explore how we're doing in the US today, please select "What If" from the Navigation Menu.  If it is not already open, select the "Status Quo" scenario.  Then tap on the box labeled "Atmospheric Waste".  You'll see a pie chart, and above it a total of 16.8 million tons of CO2 per day.  The US has a population of 308,745,472 people, from which we can calculate our current CO2 emissions as 19.8 tons per person per year.  Ten times our fair share.  Let's see what we could do to fix that.

First, create a new scenario by tapping on the title in the "What If" view, then tap on the "New" button, and then the "Open Button".  You'll start out with exactly the same situation as the "Status Quo" scenario.   As a first step, let's switch to solar and wind power.  To do this, tap on the box labeled "Electricity", and drag all the sliders to the left except for Solar and Wind.  (You'll probably need to increase solar and wind first).  Tap "Save", and then tap on the "Atmospheric Waste" box again.  Now the total CO2 output is 9 million tons per day, which is 11 tons per person per year, still a factor of 5.5 too high.

But remember above when we decreased energy use in our homes?  Let's account for that.  Tap on the box labelled "Homes" and drag the slider for energy efficiency all the way to the right.  This cuts household energy use in half, from 68.3 kWh per day to 34.1 kWh per day.  Let's also assume solar space heating for everyone, by dragging that slider all the way to the right.  Now the household energy consumption is down to 24.6 kWh per day.  Taking a look at Atmospheric Waste, we see that CO2 is now 8.4 million tons per day, a small decrease which still leaves us at 9.9 tons per person per year, 5x too high.  Note that this change is small because we're getting all our electricity from solar and wind now, which generate no CO2.

There are some other changes we can make.  One is to buy less stuff.  Tap on the box labelled "Retail Consumption", and drag the slider "Discretionary Consumption" all the way to the left.  This cuts down the amount of stuff we buy by 50%.  Tap "Save" and then look at "Atmospheric Waste" again.  It is now down to 6.4 million tons per day, which is 7.6 tons per person per day, 3.8x our fair share.

Now let's switch to electric cars.  Tap on the box labeled "Personal Travel".  Drag the slider labeled "Electric" all the way to the right and tap "Save".  Tap again on "Atmospheric Waste".  We are now down to 2.2 million tons of CO2 per day,  or 2.6 tons of CO2 per person per year.

One last thing to get us there - let's make manufacturing more efficient.  Tap on the box labelled "Manufacturing".  Drag the slider labelled "Energy Efficiency" all the way to the right.  Also drag the slider "Manufacturing Commodity Waste" all the way to the left.  Tap "Save" and take a look at "Atmospheric Waste".  1.5 million tons of CO2 per day, which is 1.8 tons per person per year - we did it!  And with some to spare, which meas we don't have to decrease our meat consumption as much as we otherwise would to reach our fair Earth share for meat consumption.

Adding it All Up

While we didn't look at all the aspects of one plant living, we got a taste of what it would be like:

  • Cut out food waste at home and in restaurants
  • Eat half as much meat
  • Switch to power generation that is predominantly solar and wind.  Nuclear would also be an option.
  • Make houses much more efficient in heating, cooling and lighting
  • It's pretty hard to decrease diving to the level we would need, but living closer to each other would help, and having electric cars would defray that main negative impact of cars - generating CO2 - provided we are using wind and solar (or nuclear) for electricity.
  • Finally, make manufacturing more efficient in terms of energy and material use, and cut discretionary consumption in half.
The infrastructure changes would be massive, but they don't require any magical new technologies.  Making those changes would use huge amounts of resources that we have not talked about here, but that is a one-time expense.

Given that we made all those changes, our daily experience wouldn't be extremely different - we'd still be living comfortably.  And we might end up spending less time working, because we'll be spending less money on discretionary consumption and won't have to produce as much stuff.

Guess Who's Coming to Dinner?

One thing we have not discussed is that fact that another two billion people will be showing up in the next several decades.  This decreases the fair Earth share for each individual inhabitant by about 29%.  And, at the same time, many people now in poverty will be moving into the middle class. That means they'll want to eat meat, drive cars, have more living space, and use more electricity.

So we'll need to do a lot more than was outlined above to live sustainably on our one planet.  There are some interesting possibilities for addressing this challenge, such as vertical farms (see The Vertical Farm: Feeding the World in the 21st Century, by Dickson Despommier).  Play around with the "What-If" interface to get more ideas to help us create a sustainable future!