An amazing night-time photo from the International Space Station showing how human settlement along the Nile River and Delta stand out against the Sahara Desert (shot by Astronaut Doug Wheelock). Click here for a larger image.

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Courtesy of EMP via Gizmodo via Astro_Wheels via defcon_5

In 40 years, there will be about 3 billion additional people living on the Earth (~9.5 billion total).   With all of these new folks, it’s easy to think about the added demands of energy, food, and water required to sustain their lifestyles.  And in terms of climate warming, it’s hard to escape the fact that significantly greater energy consumption will lead to rising rates of carbon emissions, unless there’s a shift to decarbonize the economy.

In this week’s early Edition of the Proceedings of the National Academy of Sciences (open access), Brian O’Neill and colleagues note that emissions are not just controlled by the sheer size of the human population but also by important demographic changes.

For example, how might an aging or more urban population affect emissions?  How about changes in household size?  Modelers of carbon emissions don’t usually ask these kinds of questions, so the conventionally projected emissions might be off if these additional demographic details matter.

The researchers developed a global economic model (Population-Environment-Technology, or PET) in which they specified relationships between demographic factors like houshold size, age, and urban/rural residency and economic factors like the demand for consumer goods, wealth, and the supply of labor.  Here’s a bit more on how this works:

In the PET model, households can affect emissions either directly through their consumption patterns or indirectly through their effects on economic growth in ways that up until now have not been explicitly accounted for in emissions models. The direct effect on emissions is represented by disaggregating household consumption for each household type into four categories of goods (energy, food, transport, and other) so that shifts in the composition of the population by household type produce shifts in the aggregate mix of goods demanded. Because different goods have different energy intensities of production, these shifts can lead to changes in emissions rates. To represent indirect effects on emissions through economic growth, the PET model
explicitly accounts for the effect of (i) population growth rates on economic growth rates, (ii) age structure changes on labor supply, (iii) urbanization on labor productivity, and (iv) anticipated demographic change (and its economic effects) on savings and consumption behavior.

Although there are some exceptions, households that are older, larger, or more rural tend to have lower per capita labor supply than those that are younger, smaller, or more urban. Lower-income households (e.g., rural households in developing countries) spend a larger share of income on food and a smaller share on transportation than higher-income households. Although labor supply and preferences can be influenced by a range of nondemographic factors, our scenarios focus on capturing the effects of shifts in population across types of households.

To project these demographic trends, we use the high, medium, and low scenarios of the United Nations (UN) 2003 Long-Range World Population Projections combined with the UN 2007 Urbanization Prospects extended by the International Institute for Applied Systems Analysis (IIASA) and derive population by age, sex, and rural/urban residence for the period of 2000–2100.

What did they find?

Although a shift to older and more urban household types occurs in all regions, changes in urbanization levels are most pronounced in China, sub-Saharan Africa, and the ODC [Other Developing Countries] region. Changes in household age strongly affect the European Union (EU) and other industrialized countries (OIC) regions as well as Latin America. Household size changes are largest in India, ODC, and Latin America.

….Results show that the effects of changes in population composition can have a significant influence on emissions in particular regions, separate from the effect of changes in population size. Aging can reduce emissions in the long term by up to 20%, particularly in industrialized country regions. Aging affects emissions in the PET model primarily through its influence on labor supply. In the model, aging populations are associated with lower labor productivity or labor force participation
rates at older ages, which (ceteris paribus) leads to slower economic growth. In contrast, urbanization can lead to an increase in projected emissions by more than 25%, particularly in developing country regions, also mainly through effects on labor
supply. The higher productivity of urban labor evident in the household surveys implies that urbanization tends to increase economic growth. Although other studies find that, controlling for income, urban living can be more energy efficient, survey data for urban households include income effects and therefore result in increased emissions.

In most regions, changes in household size have little additional effect on emissions beyond those already captured by aging (older households are also typically smaller). This result could be because of limitations in our household projections, which include household size changes driven by aging and urbanization but only capture the effects of behavioral change on household size in China and the United States. In China, reduced household size leads to lower emissions, a direction of influence counter to previous results. The reduction is driven primarily by the fact that large
households in older age categories typically have greater per capita labor supply (and income) than smaller households, because they include adult children of working age. Thus, aging, combined with a decline in household size, leads to a reduction in
per capita labor supply as older households become composed primarily of the elderly.

And the overall take-home message on emissions reductions?

[R]educed population growth could make a significant contribution to global emissions reductions. Several analyses have estimated how much emissions would have to be reduced by 2050 to meet long-term policy goals such as avoiding warming of more than 2 °C or preventing a doubling of CO2 concentrations through implementation of a portfolio of mitigation measures characterized as “stabilization wedges”. Our estimate that following a lower population path could reduce emissions 1.4–2.5 GtC/y by 2050 is equivalent to 16–29% of the emission reductions necessary to achieve these goals or approximately 1–1.5 wedges of emissions reductions. By the end of the century, the effect of slower population growth would be even more significant, reducing total emissions from fossil fuel use by 37–41% across the two scenarios.

O’Neill, B., Dalton, M., Fuchs, R., Jiang, L., Pachauri, S., & Zigova, K. (2010). Global demographic trends and future carbon emissions Proceedings of the National Academy of Sciences, 107 (41), 17521-17526 DOI: 10.1073/pnas.1004581107

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Photo credit: adwriter

I remember driving on a freeway in Phoenix after midnight in 1990.  The temperature was a cool 102 degrees F after breaking the all-time heat record of 126 F that day.  Deserts are good at cooling off at night.  But with all of the built environment in Phoenix storing heat from the day, the sidewalks, roads, and even swimming pools felt like they were being heated.

We all have probably experienced urban heat islands—the mass of dark asphalt and concrete absorbing solar radiation and radiating it back to space as heat.  The lack of water exacerbates the situation because there is little-to-no evaporative cooling.  Waste heat from cars, machines, air conditioners, and even human bodies also heat up the air.  And the warmer it gets, the stronger the tendency to crank up the air conditioners, generating even more waste heat.

The problem is potentially large in areas like the Middle East, India, parts of Africa, and the American Southwest, where rapid urbanization in warm, dry environments has the potential to make some urban areas much warmer at night than surrounding rural areas.

In a forthcoming article in Geophysical Research Letters¹, Mark McCarthy and colleagues at the Met Office, Hadley Centre, UK used a climate model that examines what climate might look like in a doubled CO₂ world and calculates the added warming caused by urbanization and wasted heat.

Their results were eye-opening:

• Urban regions in places like the Arabian Peninsula, Iran, and India may experience night time warming by as much as 3-5 degrees C above and beyond that caused by doubled CO₂ alone.
• The number of hot nights per year (defined as temperatures in the 99th percentile of nonurban areas) increase in the following cities:
  • London: 1-2 hot nights now vs. up to 10 hot nights in 2050
  • Sydney: 1-2 hot nights now vs. up to 15 hot nights in 2050
  • Delhi: 5-10 hot nights now vs. up to 30 hot nights in 2050
  • Beijing: 3-6 hot nights now vs. up to 50 hot nights in 2050
  • Los Angeles: 8-12 hot nights now vs. up to 40 hot nights in 2050
  • Tehran: 20 hot nights now vs. up to 60 hot nights in 2050
  • Sao Paulo: <5 hot nights now vs. up to 80 hot nights in 2050
  • Lagos (Nigeria): <5 hot nights now vs. up to 150 hot nights in 2050

As mentioned in an earlier post, we only need to remember Chicago in 1995 to recall the deadly impact that heat waves can have on urban people.  And as we saw in that unfortunate example, the victims were disproportionately the elderly and African American.

Although we may not be able to mitigate this warming, basic adaptation steps should be set into motion, including re-thinking urban design, making cities more resilient to hot environments, developing better energy and technology solutions (including cooling), installing green roofs, and putting into place emergency disaster plans and social safety nets for vulnerable populations.

¹Mark McCarthy, Martin Best, and Richard Betts (2010). Climate change in cities due to global warming and urban effects Geophysical Research Letters : 10.1029/2010GL042845

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Photo Credit:

The issue of land use change is a complex, with many factors being important historically, such as

• population growth (more land required for more people)
• technology (e.g., automobiles made suburban expansion feasible)
• economics (cheaper land and rents in suburbs compared to cities)
• policy (things like 30-yr mortgages, mortgage insurance, and FHA loans had a large impact on urban sprawl because they often made it cheaper to own rather than rent)
• cultural values (the romanticized notion of a detached home in a safe, pollution-free neighborhood with good schools)

In this week’s PLoS One, Robert McDonald and colleagues¹ examined land use change for 274 metro areas (figure 1) in the U.S. to determine tends across cities.

Their results were interesting (excerpts):

• 1.4 million ha of open space was lost, and the amount lost in a given city was correlated with population growth.
• American cities vary by more than an order of magnitude in their MSA-wide per capita land consumption. Generally large cities have small per capita land consumption, with the five smallest in 2000 being New York (459 m²/person), Miami (476 m²/person), Philadelphia (519 m²/person), Los Angeles (535 m²/person), and Washington, DC (536 m²/person). Conversely, many small cities have large per capita land consumption, with the five biggest in 2000 being Grand Forks, ND (5394 m²/person), Bismark, ND (3913 m²/person), Flagstaff, AZ (3381 m²/person), Enid, OK (3249 m²/person), and Cheyenne, WY (3073 m²/person).
• The per capita land consumption (m²/person) of most cities decreased on average over the decade from 1,564 to 1,454 m ²/person, but there was substantial regional variation and some cities even increased.
• Cities with greater conservation funding or more reform-minded zoning tended to decrease in per capita land consumption (scroll to table 1) more than other cities.
• The inequality of land consumption varied geographically, with less inequality on the East Coast compared to the West Coast (scroll to figure 4).

They provide a simplified snapshot of how development changes with history and geography (for a more-thorough yet readable treatment of land use in the U.S., check out Crabgrass Frontier by Kenneth Jackson):

The process of development plays out differently in cities with different socioeconomic histories. Moreover, cultural differences exist among and within many U.S. cities, leading to varying spatial patterns of development. However, a general historical pattern exists. In many U.S. cities, an urban core existed in the decades or centuries prior to the widespread use of the automobile, and these neighborhoods have high population density and small amounts of developed area per capita. The surrounding suburban and exurban areas, created predominately after WWII, contain residents living at lower population density and consume more land per capita. There are substantial economic links between these two zones, and in contemporary U.S. cities commuting occurs in both directions. Northeast U.S. cities that developed before the automobile typically follow this narrative. Many have a relatively dense urban core, but have adopted zoning policies that ensure contemporary suburban settlements occur at lower density. While they remain dense compared to other U.S. cities, they are getting less dense over time, as proportionally more of the population is in suburban areas. The declining manufacturing cities of the Rust Belt and the Southern Appalachians are an extreme example of this spreading out of population.

Southeastern U.S. cities, excluding Florida, are often newer and have less of a legacy of a dense urban core. They do not appear to be getting markedly denser, and the relatively fast population growth of these cities implies that their total impact on natural habitat in coming decades will be large. In contrast to the Southeast, Western cities appear to be getting denser, including those that do not have a historical legacy of a dense urban core such as Phoenix. These Western cities are often still growing quickly and consuming a great deal of land, but contemporary development is making these cities denser than they were previously. Many of these Western cities have a strong conservation culture, and the degree of conservation funding and reform-minded zoning correlates with how much denser they are getting. However, it should be noted that contemporary development in Western cities is still well below the densities found in the dense urban core of Northeastern U.S. cities, posing problems for designing effective public transit systems.

¹McDonald, R., Forman, R., & Kareiva, P. (2010). Open Space Loss and Land Inequality in United States’ Cities, 1990–2000 PLoS ONE, 5 (3) DOI: 10.1371/journal.pone.0009509

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Photo Credit:  http://www.flickr.com/photos/bobjagendorf/ / CC BY-NC 2.0

Home weatherization and efficiency upgrades can make a big difference in U.S. carbon emissions.  As we saw in a previous post, American households (including personal transportation) are responsible for

• 38% of the overall US carbon emissions
• 8% of global emissions
• more emissions of any single country except China

Unfortunately, there’s a big disconnect between things we can do to to save home energy and the ability for folks to pay for these improvements. New insulation, solar hot water, solar photovoltaics, high-efficiency furnaces: Take your pick….Each can cost $10k or more.

Fortunately, there are a lot of creative ideas coming to the rescue to help people defray these up-front costs:

• Municipalities can issue bonds that homeowners can borrow from to pay the up-front costs of improvements.  The costs of these improvements are then payed back over an extended periods of time through raised property taxes.  Homeowners effectively get a zero-interest loan from their cities.
• Banks can issue higher mortgages that include up-front costs for major energy efficiency improvements.  These added costs are then spread out over the life of the mortgage, resulting in manageable monthly payments for homeowners.
• Or, the federal government can simply reimburse people for part of the costs of improvements.  The so-called “Cash for Caulkers” program reported today by CNN is an example.

These kinds of programs make a lot of sense and have the potential to be game changers, along with helping Americans transition to electric vehicles as soon as possible.

Related post:  Behavioral changes at home can have big impacts on U.S. emissions

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Photo credit:  http://www.flickr.com/photos/nicksee/ / CC BY-NC 2.0

Let’s take a look at five innovative and exciting ideas from Stanford University, City College of New York,  Western Michigan University, UC-Davis, and the University of Arizona…

(1) Stanford moves aggressively to cut energy use, reduce carbon impact

For those of us who have worked through campus climate action plans, one of the hardest things to deal with is emissions from steam plants.  Stanford is trying to tackle this by starting with energy recapture and conservation.  Their plan is significant because it’s potentially transferable to other schools, especially in warmer climates that use heating and cooling at the same time.  And it focuses on conservation first—usually a smart and cost-effective approach.

Excerpts:

• In an effort to tackle the threat of global climate change head on, Stanford University has developed an ambitious, long-range, $250 million initiative to sharply reduce the university’s energy consumption and greenhouse gas emissions.
• Changes outlined in the Energy and Climate Plan could reduce the campus carbon impact by as much as 20 percent below 1990 levels by 2020, far exceeding the aggressive goals of California’s landmark AB 32 Global Warming Solutions Act.
• Unexpectedly, they discovered that over half the university’s heating demands could be met with heat that is already being removed from buildings by the campus cooling system. Such a reuse of energy would cut the amount of natural gas burned for heating purposes dramatically, reducing energy costs as well as emissions of greenhouse gases.
• Reconfiguring the university’s heating and cooling scheme, despite the $250 million price tag, would save money over the next four decades. Energy, water, and other operating cost savings are expected to be about $639 million from 2010 to 2050, after repayment of the initial capital investment.
• The energy-reduction plan revolves around this fact: Campus cooling systems do their job by using chilled water to remove unwanted heat from buildings. For years, that unwanted heat has been piped away from the buildings in the form of warm water, only to be discharged into the air through evaporative cooling towers at the central plant.
• That’s enough spare heat to take care of half of the campus heating needs. The result is that much less natural gas would be burned to warm offices, classrooms, dormitories and laboratories.

(2) City College of New York to offer master program in sustainability in the urban environment

Another example of an institution breaking down traditional divides—in this case architecture, engineering, and science—in the name of curricular initiatives that provide meaningful sustainability training.  Their goals are important, but if there’s anything missing, it’s contributions from sociology and psychology.  These other frames will be key for linking people and the built environment.  Otherwise, there’s a risk that these programs will deliver myopic, techno-driven conceptions of sustainability that are blind to cultural disparities and needs.

Excerpts:

• The program’s core curriculum lays a foundation in sustainability values, strategies and metrics through coursework in urban and natural systems, environmental economics and industrial ecology.  It draws upon approaches such as ‘whole systems thinking’ and life cycle analysis to understand and evaluate complex urban eco-systems.
• An interdisciplinary capstone project, which requires teamwork and interchange among groups of architects, engineers and scientists, will develop experience with the processes and dynamics of integrated design.  Additionally, students will take electives in relevant advanced courses within architecture, engineering and science.
• Graduates will ultimately develop leadership and teamwork skills that will give them an advantage in diverse professional settings where interaction and collaboration among teams of scientists, engineers, architects and others are commonplace.

(3) Western Michigan University getting $1 million for green manufacturing

University-business relationships like this are terrific for showing how university leverage and resources can help the broader economy transition to a more-sustainable world.

Excerpts:

• WMU’s Green Manufacturing project draws upon existing research and development centers at the University. Faculty researchers and students will collaborate with area manufacturers, especially smaller businesses, to help them build greater energy efficiency into manufacturing processes and promote recycling of materials to further reduce costs. About 25 companies in Battle Creek, Kalamazoo, Benton Harbor-St. Joseph, Grand Rapids and Muskegon have already expressed interest in participating, according to Patten.
• “I am especially proud with this project,” said Dunn, “because it highlights one of the longtime strengths of Western Michigan University, which is applying the latest knowledge and technology to create practical solutions of immediate and long-term benefit.”
• “Companies realize that being green is good for their bottom line to ensure their longevity,” said Patten, who added that project will help preserve existing jobs and foster creation of new ones.

(4/5) UC-Davis and U. Arizona have incentivized alternative transportation by using rewards to entice more walking and biking.

This is a great idea, and a no-brainer for schools with climates like Davis and Tucson.  Look at how Davis’ effort to attract people goes beyond traditional appeals for carpooling.  It’s a lesson to other schools:  If you really want people to change commuting behavior, sweeten the deal.

An excerpt from UC-Davis:

• Rewards for green commuting include complimentary parking permits, discounted bus and train passes, discounts on bicycle storage lockers, shower and locker facilities for walkers and bicyclists, and options to get you home in an emergency.
• On top of all that, goClub members are eligible for prize drawings every other month. A sampling of the prizes: bus and train passes, bicycles and assorted bicycle gear, a train-and-bus trip for two to Yosemite, a one-month membership to the Activities and Recreation Center, two tickets to an athletics event of your choice, lunch coupons and UC Davis apparel.
• The old alternative transportation program listed some 1,734 participants: carpoolers and vanpoolers, and bus riders and train riders. All of these people have been automatically enrolled in the goClub.
• With the addition of walkers and bicyclists, goClub membership could grow by thousands—especially considering that bicycling accounts for more than 40 percent of campus-related transportation.

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For more information:

• AASHE bulletin 11/9/09

As I mentioned in the last post, heat waves have the potential to harm or kill a lot of people.  Who are the people most likely to suffer first? The experiences from the Chicago 1995 heat wave offer some insights for urban America.  Eric Klinenberg’s 2002 book Heat Wave: A Social Autopsy of Disaster in Chicago is as relevant as ever to the current conversation about climate change.

Some excerpts from a U. Chicago Press interview with Klinenberg.

The heat made the city’s roads buckle. Train rails warped, causing long commuter and freight delays. City workers watered bridges to prevent them from locking when the plates expanded. Children riding in school buses became so dehydrated and nauseous that they had to be hosed down by the Fire Department. Hundreds of young people were hospitalized with heat-related illnesses. But the elderly, and especially the elderly who lived alone, were most vulnerable to the heat wave.

“It’s hot,” the mayor told the media. “But let’s not blow it out of proportion. . . . Every day people die of natural causes. You cannot claim that everybody who has died in the last eight or nine days dies of heat. Then everybody in the summer that dies will die of heat.” Many local journalists shared Daley’s skepticism, and before long the city was mired in a callous debate over whether the so-called heat deaths were—to use the term that recurred at the time—”really real.”

[T]he black/white mortality ratio was 1.5 to 1.

Another surprising fact that emerged is that Latinos, who represent about 25 percent of the city population and are disproportionately poor and sick, accounted for only 2 percent of the heat-related deaths…Chicago’s Latinos tend to live in neighborhoods with high population density, busy commercial life in the streets, and vibrant public spaces. Most of the African American neighborhoods with high heat wave death rates had been abandoned—by employers, stores, and residents—in recent decades. The social ecology of abandonment, dispersion, and decay makes systems of social support exceedingly difficult to sustain.

The heat wave was a particle accelerator for the city:  It sped up and made visible the hazardous social conditions that are always present but difficult to perceive. Yes, the weather was extreme. But the deep sources of the tragedy were the everyday disasters that the city tolerates, takes for granted, or has officially forgotten.

Related Post: Say so long to your furnace and hello to a new air conditioner

photo credit:  http://www.flickr.com/photos/paraflyer/ / CC BY-ND 2.0

Defining and describing what constitutes “the good life” for individuals and communities has been a vexing challenge for social scholars…

So begins a recent article^1,2 in Environment and Behavior (subscription required)

…[T]he term “life satisfaction”, which comes from the psychological literature, refers to the cognitive evaluation of one’s happiness or subjective wellbeing and involves comparing the fulfillment of individual needs, goals, and aspirations to a meaningful standard.

One unique aspect of this study was that the team used surveys to assess people’s life satisfaction at two different scales: (1) their own lives and (2) their neighborhoods.

Bottom line:

• Income and home ownership mattered more to individual satisfaction compared to satisfaction with neighborhoods.
• In contrast, neighborhood satisfaction was more strongly correlated with social capital (shared knowledge, norms, rules, and networks that facilitate collective experience) and satisfaction with the natural environment in the neighborhood.
• These results corroborate a large body of prior research indicating that wealth alone is not the only explanation for life satisfaction–our communities and environments matter as well.
• Given that more people now live in urban environments than at any point in human history, this speaks to the need for (re)developing cities to promote green spaces and social networks.

¹Vemuri, A., et al. (2009) A Tale of Two Scales: Evaluating the Relationship Among Life Satisfaction, Social Capital, Income, and the Natural Environment at Individual and Neighborhood Levels in Metropolitan Baltimore. Environment and Behavior, (Online First edition).

²Bowdoin people can link to the article here.

photo credit: http://www.flickr.com/photos/kevinl8888/ / CC BY-NC-ND 2.0