Category Archives: Peer Reviewed Article Review

open source street noise model

Here’s an open-source code for modeling street noise propagation. It’s written in R and open source database and GIS tools.

This paper describes the development of a model for assessing TRAffic Noise EXposure (TRANEX) in an open-source geographic information system. Instead of using proprietary software we developed our own model for two main reasons: 1) so that the treatment of source geometry, traffic information (flows/speeds/spatially varying diurnal traffic profiles) and receptors matched as closely as possible to that of the air pollution modelling being undertaken in the TRAFFIC project, and 2) to optimize model performance for practical reasons of needing to implement a noise model with detailed source geometry, over a large geographical area, to produce noise estimates at up to several million address locations, with limited computing resources. To evaluate TRANEX, noise estimates were compared with noise measurements made in the British cities of Leicester and Norwich. High correlation was seen between modelled and measured LAeq,1hr (Norwich: r = 0.85, p = .000; Leicester: r = 0.95, p = .000) with average model errors of 3.1 dB. TRANEX was used to estimate noise exposures (LAeq,1hr, LAeq,16hr, Lnight) for the resident population of London (2003–2010). Results suggest that 1.03 million (12%) people are exposed to daytime road traffic noise levels ≥ 65 dB(A) and 1.63 million (19%) people are exposed to night-time road traffic noise levels ≥ 55 dB(A). Differences in noise levels between 2010 and 2003 were on average relatively small: 0.25 dB (standard deviation: 0.89) and 0.26 dB (standard deviation: 0.87) for LAeq,16hr and Lnight.

 

green infrastructure, happiness, and the ginkgo-stinkgo tree

Do trees make people happy? Well yes, I think most people subjectively just have a sense this is true. But for the cynics out there, there is also hard scientific evidence. People have tried all sorts of economic approaches – correlations with real estate markets and willingness-to-pay surveys – for example, to try to estimate the value people place on trees. (Can you measure happiness in dollars? The average man on the street might say no, but the average economist might say it’s the best of many imperfect options for measuring value.) Medical researchers have tried having people walk around cities with brain scanners on their heads. This is a new one to me though – correlating tree coverage with antidepressant prescriptions. And the correlation is there.

Growing evidence suggests an association between access to urban greenspace and mental health and wellbeing. Street trees may be an important facet of everyday exposure to nature in urban environments, but there is little evidence regarding their role in influencing population mental health. In this brief report, we raise the issue of street trees in the nature-health nexus, and use secondary data sources to examine the association between the density of street trees (trees/km street) in London boroughs and rates of antidepressant prescribing. After adjustment for potential confounders, and allowing for unmeasured area-effects using Bayesian mixed effects models, we find an inverse association, with a decrease of 1.18 prescriptions per thousand population per unit increase in trees per km of street (95% credible interval 0.00, 2.45). This study suggests that street trees may be a positive urban asset to decrease the risk of negative mental health outcomes.

And in other urban tree news, you can collect ginkgo berries, take out the nuts, roast them and eat them. The only problem being that they stink to high heaven and are mildly poisonous. Ginkgos are very interesting trees though, sort of an ancient cross between trees and ferns if you believe this article.

Believed to be truly indigenous to only a single province in China , this 270 million year old species belongs to an ancient lineage of species that have since disappeared for one reason or another over the past few millennia, making Ginkgo biloba (known as a ‘living fossil’) the sole extant representative of what was once a vast and diverse group of organisms. In fact, the ginkgo tree is so unlike any other living plant species that this tree has it’s own genus, family, order, class and division. To put this into terms that may be easier to conceptualize: the only thing that ginkgo trees have in common with other plants is they are also plants. This means that pretty much everything about their genetic make-up, physiology, general behavior, reproductive strategies (including their mobile sperm; a trait particular to ferns, cycads and algae) and even their ability to photosynthesize is anywhere between slightly-off to fundamentally different from any other living plant. Oh, and you can eat it’s seeds…

It’s a bit of a messy operation collecting the seeds which are often produced profusely by female trees and lie unmolested by fungi, insects or most pests of any kind save for some adventurous squirrels which occasionally eat the seeds. I find some rubber or latex gloves and a plastic bag are your best bet for collecting the seeds in addition to some grubby clothes that you don’t mind smelling cheesy for a little while. The scent from the fruit tends to linger when it gets on fabric or clothing and so you might want to try extra hard to remember not to wear anything that you are particularly fond of when engaging in the participatory act of ginkgo seed collecting.

I think it’s cool that some people do this, but I personally am not going to take up this hobby right now.

A realistic leverage point for one-planet living: more compulsory vacation in the rich world

This article in System Dynamics Review advocates requiring more vacation time as a tool to decelerate growth in humanity’s ecological footprint. The idea is logical enough, but politically very hard if you ask me. The only way it might be politically possible is in the wake of a crisis, like a famine or sudden shift in climate, that is big enough to be a major wakeup call to the rich countries but small enough that it doesn’t kill a big fraction of humanity (which would decrease our ecological footprint footprint of course, but at an obviously horrible cost.)

As envisioned by Keynes in Economic Possibilities for our Grandchildren, reducing work hours could make sense if it is done in parallel with productivity and wealth increases, and policies that address a fair distribution of the new wealth created by those productivity increases. This brings us back to trying to steer economic and technological growth in a more sustainable direction, trying to at least postpone and limit the next crisis, but having some ideas on how we might take advantage of the next crisis when it happens, while hoping it is not the one that wipes us out.

William Lazonick vs. Wally

Still thinking about my William Lazonick post from yesterday. One of his arguments is that it is not just stockholders that deserve a part of corporate returns, because they are not the only ones taking risk. As he explains in his working paper, taxpayers and employees also take risk:

Then I show how and why MSV [maximizing shareholder value] is a theory of value extraction that, when applied to corporate resource allocation in the United States, has undermined the social conditions of innovative enterprise and resulted in employment instability and income inequity. I refute the fundamental economic assumption of MSV that of all participants in the business corporation it is only shareholders who bear risk and hence have a claim on profits if and when they occur. Taxpayers in funding government spending on productive resources that are essential to the innovation process and workers in supplying effort to the processes of organizational learning that are the essence of innovation make productive contributions to the enterprise without guaranteed returns. Indeed I argue that public shareholders do not in general invest in the innovation process but just extract value from it, and hence bear little, if any, risk of the failure of that process. I summarize a growing body of empirical research that shows that since the 1980s, backed by MSV ideology, financial interests, including top corporate executives, have been able to extract vast amounts of value from US industrial corporations in excess of value that they may have helped to create.

I contacted Future Yada Yada workplace effort correspondent Wally from Dilbert, who offered the following. (sorry, you have to click – I’m a huge Scott Adams fan but I don’t see an easy, unambiguously 100% legal way to embed his graphic here)

a 1200-year drought

How bad is the drought in California? So bad that based on historical data, you would only expect it to happen once in 1200 years, on average, according to Geophysical Research Letters.

For the past three years (2012-2014), California has experienced the most severe drought conditions in its last century. But how unusual is this event? Here we use two paleoclimate reconstructions of drought and precipitation for Central and Southern California to place this current event in the context of the last millennium. We demonstrate that while 3-year periods of persistent below-average soil moisture are not uncommon, the current event is the most severe drought in the last 1200 years, with single year (2014) and accumulated moisture deficits worse than any previous continuous span of dry years. Tree-ring chronologies extended through the 2014 growing season reveal that precipitation during the drought has been anomalously low but not outside the range of natural variability. The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures.

There are some eye-opening pictures of dry farm fields here.

more on automated data synthesis

Here’s another article from Environmental Modeling and Software about automated synthesis of scattered research results:

We describe software to facilitate systematic reviews in environmental science. Eco Evidence allows reviewers to draw strong conclusions from a collection of individually-weak studies. It consists of two components. An online database stores and shares the atomized findings of previously-published research. A desktop analysis tool synthesizes this evidence to test cause–effect hypotheses. The software produces a standardized report, maximizing transparency and repeatability. We illustrate evidence extraction and synthesis. Environmental research is hampered by the complexity of natural environments, and difficulty with performing experiments in such systems. Under these constraints, systematic syntheses of the rapidly-expanding literature can advance ecological understanding, inform environmental management, and identify knowledge gaps and priorities for future research. Eco Evidence, and in particular its online re-usable bank of evidence, reduces the workload involved in systematic reviews. This is the first systematic review software for environmental science, and opens the way for increased uptake of this powerful approach.

land economics

Here’s a long open article from Ecological Economics about studying the competition for land. Land exists at the intersection of economics and ecology, and it is conspicuously absent from a lot of economic thinking. It can be thought of as capital, in a sense, but obviously it is not manufactured capital. We can’t make more of it, but we can intensify our activities on a given piece of it (for example, more intense agriculture or taller buildings). Land is the obvious source of a lot of ecosystem services, but the value of those services tends to accrue regionally or globally rather than to the landowner. These are my own thoughts, but anyway here is the abstract:

Possible negative effects of increased competition for land include pressures on biodiversity, rising food prices and GHG emissions. However, neoclassical economists often highlight positive aspects of competition, e.g. increased efficiency and innovation. Competition for land occurs when several agents demand the same good or service produced from a limited area. It implies that when one agent acquires scarce resources from land, less resource is available for competing agents. The resource competed for is often not land but rather its function for biomass production, which may be supplanted by other inputs that raise yields. Increased competition may stimulate efficiency but negative environmental effects are likely in the absence of appropriate regulations. Competition between affluent countries with poor people in subsistence economies likely results in adverse social and development outcomes if not mitigated through effective policies. The socioecological metabolism approach is a framework to analyze land-related limits and functions in particular with respect to production and consumption of biomass and carbon sequestration. It can generate databases that consistently link land used with biomass flows which are useful in understanding interlinkages between different products and services and thereby help to analyze systemic feedbacks in the global land system.

more trees!

This article in Landscape and Urban Planning is all about street trees. You would think this topic would have been exhausted, that is the technology would have been perfected, by now. And it has, in a few places. I am convinced it is not that leading edge knowledge about trees needs to be advanced all that much, but most cities are completely ignorant of what the best practices are. People in charge don’t know what they don’t know and have zero interest in finding out.

Street trees are an integral element of urban life. They provide a vast range of benefits in residential and commercial precincts, and they support healthy communities by providing environmental, economic and social benefits. However, increasing areas of impermeable surface can increase the stresses placed upon urban ecosystems and urban forests. These stresses often lead tree roots to proliferate in sites that provide more-favourable conditions for growth, but where they cause infrastructure damage and pavement uplift. This damage is costly and a variety of preventative measures has been tested to sustain tree health and reduce pavement damage. This review explores a wide range of literature spanning 30 years that demonstrates the benefits provided by street trees, the perceptions of street trees conveyed by urban residents, the costs of pavement damage by tree roots, and some tried and tested measures for preventing pavement damage and improving tree growth.

walkability matters – duh

For people still looking for an answer to the question “does walkability matter?”, here is some more solid evidence from Cities to add to the mountain.

In this study, researchers examined 170 neighborhoods in a medium-sized city to see whether walkability influences neighborhood sustainability. Until 2008, there had not been a reliable measure of the social, health, and economic impact of walkable neighborhoods. This dramatically changed when scholars were able to quantify walkability with tools such as Walkscore™; which measures how accessible daily living activities are by foot. The researchers investigated how walkability impacts the quality and sustainability of a neighborhood. They developed models that evaluated the correlation between an area’s Walkscore™ and four broad measures of urban sustainability: neighborhood housing valuation; foreclosures; and crime. Our analysis shows a positive impact not only on neighborhood housing valuation but also on neighborhood crime and foreclosure. These results provide policy opportunities for planners and citizen groups to pursue strategies to encourage the development of more walkable and sustainable neighborhoods.

I know I’m a broken record, but getting around under our own muscle power for most trips most of the time is the key to (in no particular order):

  • reducing carbon emissions
  • reducing air pollution from vehicle emissions, especially particulates which cause asthma and heart disease – this will add quality years to all our lives
  • solving drunk driving
  • saving lots and lots of money that we used to spend on cars
  • saving enormous amounts of space in cities that used to be used for car maneuvering and parking – space that can now be used for relaxing, recreating, habitat, housing, economic or commercial activity
  • creating space for people – yes, you can increase density and reduce crowding at the same time
  • increasing physical health through more physical activity, decreasing obesity, diabetes and heart disease, adding years to peoples’ lives
  • improving psychological health through physical activity
  • increasing social interaction
  • increasing business activity and profits
  • creating an ecosystem of innovative, creative people, businesses, nonprofit and government agencies

growth, sustainability, and employment

This article in Ecological Economics looks at economic growth, sustainability, and employment together:

Two empirical correlations are studied: one between economic growth and environmental impacts, and the other between the lack of economic growth and unemployment. It is demonstrated that, at a global level, economic growth is strongly correlated with environmental impacts, and barriers to fast decoupling are large and numerous. On the other hand, low or negative growth is highly correlated with increasing unemployment in most market economies, and strategies to change this lead to difficult questions and tradeoffs. The coexistence of these two correlations – which have rarely been studied together in the literature on “green growth”, “degrowth” and “a-growth” – justifies ambivalence about growth. To make key environmental goals compatible with full employment, the decoupling of environmental impacts from economic output has to be accompanied by a reduction of dependence on growth. In particular, strategies to tackle unemployment without the need for growth, several of which are studied in this article, need much more attention in research and policy.

I get it – growth and employment are often looked at together in the mainstream economic literature, obviously. Employment is pretty important to living standards and social/political stability. Sustainability and growth are often looked at together in the sustainability literature (which is “mainstream” to some, but not really to most economists). There is an obvious tradeoff between the two as long as our economy devours large amounts of natural resources and produces enormous amounts of waste and pollution. The idea of “decoupling” is that each unit of growth gets slightly greener and cleaner over time. But unfortunately, that process does not seem to be nearly fast enough to prevent eventual collapse. Damage to natural ecosystems is increasing and will eventually threaten the ecosystem services that our human civilization depends on. That is the trend we are on. The only two ways out are to slow growth or to accelerate the decoupling process. This article seems to focus on the former. My opinion is that this path is politically impossible unless it is precipitated by some serious crisis, which we can’t just sit around and wait for because it could cause enormous pain and suffering. So the latter option is the only hope. It is hard but entirely possible if enough people understand the situation and dedicate their efforts to make it happen.