Age related CO2 Emissions

Zagheni, E. (2011) The Leverage of Demographic Dynamics on Carbon Dioxide Emissions: Does Age Structure Matter? Demography. Volume 48, Issue 1, pp 371-399. (ungated version)

Abstract:

This article provides a methodological contribution to the study of the effect of changes in population age structure on carbon dioxide (CO2) emissions. First, I propose a generalization of the IPAT equation to a multisector economy with an age-structured population and discuss the insights that can be obtained in the context of stable population theory. Second, I suggest a statistical model of household consumption as a function of household size and age structure to quantitatively evaluate the extent of economies of scale in consumption of energy-intensive goods, and to estimate age-specific profiles of consumption of energy-intensive goods and of CO2 emissions. Third, I offer an illustration of the methodologies using data for the United States. The analysis shows that per-capita CO2 emissions increase with age until the individual is in his or her 60s, and then emissions tend to decrease. Holding everything else constant, the expected change in U.S. population age distribution during the next four decades is likely to have a small, but noticeable, positive impact on CO2 emissions.

Related Links:

• An Estimate of the Age Distributionís Effect on Carbon Dioxide Emissions
• How to cut carbon emissions: don’t be middle-aged
• Hans Rosling explains population growth and climate change
• Food Production, Population Growth, and the Environmet

A universal model for mobility patterns

This is one of the best papers I have read in the last few years. Neat stuff! 

Simini, F; Gonzalez. MC; Maritan; A; Barabasi, AL. (2012). A universal model for mobility and migration patterns. Nature 484, 96–100. (ungated link)

Abstract:

Introduced in its contemporary form in 1946, but with roots that go back to the eighteenth century, the gravity law is the prevailing framework with which to predict population movement, cargo shipping volume and inter-city phone calls, as well as bilateral trade flows between nations. Despite its widespread use, it relies on adjustable parameters that vary from region to region and suffers from known analytic inconsistencies. Here we introduce a stochastic process capturing local mobility decisions that helps us analytically derive commuting and mobility fluxes that require as input only information on the population distribution. The resulting radiation model predicts mobility patterns in good agreement with mobility and transport patterns observed in a wide range of phenomena, from long-term migration patterns to communication volume between different regions. Given its parameter-free nature, the model can be applied in areas where we lack previous mobility measurements, significantly improving the predictive accuracy of most of the phenomena affected by mobility and transport processes.

ps. I've postponed this post for far too long because I was planning to start a study with some testing on the radiation model using Brazilian data (commuting, migration, national flights). However, I might face some (good!) turbulence in my professional/academic life in the next few months and I don't know when I'll get time for that.

Commuting landscapes (Fig 4)

[Image Source: Simini et al, 2011]

Tracking Trash

Abstract:

Using active self-reporting tags, the authors followed 2,000 objects through Seattle's waste management system. By making the waste "removal chain" more transparent, they help reveal the disposal process of everyday objects, highlighting potential inefficiencies in the current removal system.

This paper is one of the publications from 'Trash Track', a research project led by Carlo Ratti at the MIT SENSEable City Lab. I haven't read the paper. Still, this empirical strategy sounds as one of the most sharp ideas I've heard in the last couple of years. It' a very appealing and straightforward idea and it raises great potential impact for public policy. Here is a short promotional video of the project.

ps. This is the kind of idea that makes you think: "This is so obvious! Why haven't I thought of this before?"

The Future Cities Agenda, by M. Batty

Michael Batty's agenda for future cities (pdf).

The key issues on the agenda involve: automating cities which is an inevitable consequence of networking and the decentralisation of all aspects of computation across the globe; the dominance of migration as a force for local change; globalisation where everyone who uses the net is in some way part of a world city of sorts (with the implication that every city, no matter what size, has elements of ‘world city’ within it); the consequences of aging which will change the way we physically move around the city combined with the automation of transit and the private automobile; the rise of health care as a basic urban function; the demise of physical retailing and the ‘high street’, as much through online activity as through physical decentralisation; and, of course, the general automation of all sectors of the economy. Many problems confound this agenda and it is worth noting these as they are likely to dominate the extent to which we are able to build resilient and sustainable cities that are smart enough to enable them to function better than any of those we have created in the past.

Residential Location and Retirement Age

The new issue of Urban Studies is out and this paper caught my attention. It might interest some of you as well!

The Effect of Residential Location on Retirement Age: Theory and Some Evidence on Male Behaviour in the US by Jorge González Chapela

Abstract: Retirement age choice is introduced into a conventional model of residential location to show that the retirement age of workers who do not move after retirement can be influenced by the urban variation of leisure and housing prices. A retirement demand equation that incorporates commuting characteristics is estimated on a sample of US urban male owners interviewed by the Panel Study of Income Dynamics. It is found that commuters retire around two years earlier than comparable home-based workers, although the evidence provides no support for this gap to be the result of differences in leisure or housing prices across both groups.

Extra links:

• disussion paper on commuting costs and labor force retirement.
• paper The Determinants of Male´s Retirement in Urban Brazil (+book)

How many (good) research questions are there?

In the past few months, I have been thinking a lot about the question I should investigate in my PhD-project. It put me thinking about how many good research questions are there? How many of these questions I'm interested in?

Right now I'm following the steps of a great Brazilian rock/ska band to figure it out. Once, a journalist asked the band what was their secret to have so many hits. They said something like "We write down hundreds of songs a month. At the end of the year, we can keep a few good ones."

So, that's exectally what I have been doing in the last few weeks. I writing down every research question I can think of, considering my research interests (no matter how stupid, obvious, naive or ambitous they sound).

After saying all this, this TED talk here may sound a bit self-help. But it's worth seven minutes of your time.

"The simplest questions can carry you out to the edge of human knowledge"  (via Flowing Data) 

ps. Of course most of the posed questions will be discarded. The next step should be to select the few good ones (if there's any left). But first things first...

Motorways and slime mould's rationality (!?)

This is probably the  strangest  most creative  idea for paper I have seen in the last months (HT Leo via MR).



"Are motorways rational from slime mould's point of view?"

Abstract:

We analyse the results of our experimental laboratory approximation of motorways networks with slime mould Physarum polycephalum. Motorway networks of fourteen geographical areas are considered: Australia, Africa, Belgium, Brazil, Canada, China, Germany, Iberia, Italy, Malaysia, Mexico, The Netherlands, UK, USA. For each geographical entity we represented major urban areas by oat flakes and inoculated the slime mould in a capital. After slime mould spanned all urban areas with a network of its protoplasmic tubes we extracted a generalised Physarum graph from the network and compared the graphs with an abstract motorway graph using most common measures. The measures employed are the number of independent cycles, cohesion, shortest paths lengths, diameter, the Harary index and the Randic index. We obtained a series of intriguing results, and found that the slime mould approximates best of all the motorway graphs of Belgium, Canada and China, and that for all entities studied the best match between Physarum and motorway graphs is detected by the Randic index (molecular branching index).

Soundtrack: Stand Up

Housing Finance Policy and Segregation

Paavo Monkkonen has just published a paper that examines the impact of the expansion of housing finance on socioeconomic segregation in Mexican cities.

This would be a very nice hypothesis to be tested for the Brazilian case. Brazil had a huge housing finance policy from the 60's to the 80's with the National Housing Bank (BNH). Since 2009 the Federal Government has been carrying out a very big social housing program called Minha Casa, Minha Vida (My House, My Life). I think this is a good idea to consider if you are a PhD candidate in Brazil.

soundtrack: Os Mulheres Negras - Summertime