12.27.2011

12.26.2011

Geoengineering research goes mainstream

The results of this paper are not very surprising, but what is surprising is that it was published in Nature Climate Change.  This is not because the article is bad, but because the politics of publishing research on geoengineering has been remarkably hostile.

In 2007, colleagues and I (lead by Andy Lacis) wrote this paper which was well-executed and extremely interesting, but nobody would touch it.

Despite years of speculation and vague talk, peer-reviewed research on geoengineering is remarkably scarce. Nearly the entire community of geoengineering scientists could fit comfortably in a single university seminar room, and the entire scientific literature on the subject could be read during the course of a transatlantic flight. Geoengineering continues to be considered a fringe topic.  
Many scientists have been reluctant to raise the issue for fear that it might create a moral hazard: encouraging governments to deploy geoengineering rather than invest in cutting emissions. Indeed, geoengineering ventures will be viewed with particular suspicion if the nations funding geoengineering research are not also investing in dramatically reducing their emissions of carbon dioxide and other greenhouse gases. Many scientists also rightly fear that grants for geoengineering research would be subtracted from the existing funds for urgently needed climate-science research and carbon-abatement technologies. But there is a pressing need for a better understanding of geoengineering, rooted in theoretical studies and empirical field measurements. The subject also requires the talents of engineers, few of whom have joined the small group of scientists studying these techniques.
And last year (2010) I wrote a fellowship grant to look at geoengineering impacts and, perhaps not surprisingly, it did not get funded (of course, I'd like to blame that on the politics and not my lousy writing...).

Anyway, enough prologue. Here's the actual article that came out.  No real surprises, but still worthy of note for the reasons above.
Effectiveness of stratospheric solar-radiation management as a function of climate sensitivityKatharine L. Ricke, Daniel J. Rowlands, William J. Ingram, David W. Keith & M. Granger Morgan
Abstract: If implementation of proposals to engineer the climate through solar-radiation management (SRM) ever occurs, it is likely to be contingent on climate sensitivity. However, modelling studies examining the effectiveness of SRM as a strategy to offset anthropogenic climate change have used only the standard parameterizations of atmosphere–ocean general circulation models that yield climate sensitivities close to the Coupled Model Intercomparison Project mean. Here, we use a perturbed-physics ensemble modelling experiment to examine how the response of the climate to SRM implemented in the stratosphere (SRM-S) varies under different greenhouse-gas climate sensitivities. When SRM-S is used to compensate for rising atmospheric concentrations of greenhouse gases, its effectiveness in stabilizing regional climates diminishes with increasing climate sensitivity. However, the potential of SRM-S to slow down unmitigated climate change, even regionally, increases with climate sensitivity. On average, in variants of the model with higher sensitivity, SRM-S reduces regional rates of temperature change by more than 90% and rates of precipitation change by more than 50%.

a,b, Five-year running-mean global mean near-surface (1.5 m) air temperature (a) and five-year running-mean global mean precipitation rate (b), all shown over the length of the 80 model-year simulations. Copyright: Nature Climate Change.

12.23.2011

New tool for interfering with malaria transmission

Geoff Johnston, a doctoral candidate at Columbia's PhD in Sustainable Development, is on the team behind this recent study in PNAS.  He's promised us a non-technical summary soon.


Sophie H. Adjalleya, Geoffrey L. Johnston, Tao Li, Richard T. Eastman, Eric H. Ekland, Abraham G. Eappen, Adam Richman, B. Kim Lee Sim, Marcus C. S. Lee, Stephen L. Hoffman, and David A. Fidock

Abstract: Clinical studies and mathematical models predict that, to achieve malaria elimination, combination therapies will need to incorporate drugs that block the transmission of Plasmodium falciparum sexual stage parasites to mosquito vectors. Efforts to measure the activity of existing antimalarials on intraerythrocytic sexual stage gametocytes and identify transmission-blocking agents have, until now, been hindered by a lack of quantitative assays. Here, we report an experimental system using P. falciparum lines that stably express gametocyte-specific GFP-luciferase reporters, which enable the assessment of dose- and time-dependent drug action on gametocyte maturation and transmission. These studies reveal activity of the first-line antimalarial dihydroartemisinin and the partner drugs lumefantrine and pyronaridine against early gametocyte stages, along with moderate inhibition of mature gametocyte transmission to Anopheles mosquitoes. The other partner agents monodesethyl-amodiaquine and piperaquine showed activity only against immature gametocytes. Our data also identify methylene blue as a potent inhibitor of gametocyte development across all stages. This thiazine dye almost fully abolishes P. falciparum transmission to mosquitoes at concentrations readily achievable in humans, highlighting the potential of this chemical class to reduce the spread of malaria.

From the author summary:
The scale of the malaria epidemic remains vast, causing up to 225 million symptomatic infections and ∼780,000 deaths each year, primarily in sub-Saharan Africa. Despite this sobering backdrop, there are encouraging signs that treating infected individuals with antimalarial therapies and combating the Anopheles mosquito vector with insecticides can substantially reduce the burden of disease. First-line therapies rely on pairing potent derivatives of the Chinese plant extract artemisinin with longer-lasting partner drugs in regimens referred to as artemisinin-based combination therapies. Clinical reports and mathematical models indicate that additional reductions in disease incidence will require treatments that not only cure patients but also decrease the transmission of malarial parasites to Anopheles mosquitoes (1). Here, we have investigated the ability of various antimalarial agents to inhibit transmission. This work reveals that methylene blue (MB), the first synthetic compound ever used in clinical therapy (2), has potent transmission-blocking activity superior to current first-line therapies. 
Interruption of transmission can be achieved with drugs that inhibit the development of parasite sexual forms, termed gametocytes, within red blood cells. In the case of the most lethal human malaria pathogen, Plasmodium falciparum, these gametocytes progress through five developmental stages over 10–12 d before becoming infectious to mosquitoes (Fig. P1A). Prior studies have found that some drugs that target the disease-causing asexual blood stages also inhibit early stage gametocytes (3). However, identifying compounds that inhibit the metabolically less active mature stages has proven considerably more difficult, in part because of a lack of robust experimental tools. To address this concern, we have developed recombinant parasite lines and analytical methods that enable precise measurements of drug action against gametocytes as they mature and attain infectivity. 
To investigate the abilities of known antimalarials to affect gametocyte viability at different stages, we genetically modified P. falciparum parasite lines to express GFP-luciferase reporters from gene promoters known to be active in early, mid, or late stage gametocytes. The production of gametocytes was triggered by starvation-induced stress, and their subsequent development and gametocyte maturation were monitored by quantifying luciferase activity. Measurements of the rate of action of antimalarial compounds, tested at different doses in vitro, revealed the remarkable potency of the thiazine dye MB against all developmental stages (Fig. P1A). Subsequent experiments revealed that MB almost fully blocked transmission of P. falciparum gametocytes to Anopheles mosquitoes (Fig. P1B), reducing parasite infectivity by 78–100%. The small proportion of mosquitoes that were infected had a >98% reduction in the numbers of parasites developing in the midgut. Most of the effect of MB on parasite transmission can be attributed to its potent activity against mature stage V gametocytes. Parallel studies also observed a potent effect with dihydroartemisinin, the active metabolite of artemisinin compounds, with inhibition occurring primarily against early stage gametocytes. Comparable activity against early stages was observed with key partner drugs, including amodiaquine and lumefantrine (4). 
The experimental system that we developed for these studies will enable high-throughput screening to identify additional transmission-blocking compounds. Our study also provides experimental tools to further probe gametocyte biology, including studies on the cellular processes and molecular components that dictate the formation of gametocytes and promote transmission (5). A renewed emphasis on this phase of the malarial parasite life cycle, using reporter systems such as the one described here, promises to further aid expanding efforts to roll back malaria.

12.22.2011

Annual Review of Resource Economics


The Annual Reviews have come out with a new journal (a few issues old) that will be extremely useful resource for many FE readers: Annual Review of Resource Economics.
ABOUT THIS JOURNAL: The Annual Review of Resource Economics, provides authoritative critical reviews evaluating the most significant research developments in resource economics, focusing on agricultural economics, environmental economics, renewable resources, and exhaustible resources.
To get a sense of the journal, I just cut and pasted the most recent table of contents below (authors aren't listed, but many of them are quite distinguished).
Plowing Through the Data
Methods for Performance Evaluations and Impact Measurement
Green National Income and Green National Product
Behavior, Robustness, and Sufficient Statistics in Welfare Measurement
The Challenges of Improving the Economic Analysis of Pending Regulations: The Experience of OMB Circular
Commodity Booms and Busts
Food Quality: The Design of Incentive Contracts
Nutritional Labeling and Consumer Choices
Efficiency Advantages of Grandfathering in Rights-Based Fisheries Management
Game Theory and Fisheries
Natural Resource Management: Challenges and Policy Options
The New Economics of Evaluating Water Projects
Management of Hazardous Waste and Contaminated Land
The Economics of Infection Control
The Economics of Natural Disasters
Valuing Mortality Risk Reductions: Progress and Challenges
Pricing Nature
The Economics of Non-Point-Source Pollution
Microeconometric Strategies for Dealing with Unobservables and Endogenous Variables in Recreation Demand Models
The Environment and Trade
The Social Cost of Carbon
Corporate Average Fuel Economy Standards and the Market for New Vehicles 

12.20.2011

Where do I get a forecast of ENSO?

My colleagues and I have been pushing the idea that ENSO forecasts should be broadly integrated into economic, security and social policies in the tropics and subtropics.  In a talk to policy folks yesterday, I tried to point them towards an excellent resource provided by the International Research Institute for Climate and Society (at Columbia) that aggregates ENSO forecasts across many modeling groups (here).  Their current forecast for 2012 (Sep-Nov) is a 27% chance of El Nino, a 52% chance of neutral conditions and a 21% chance of La Nina.

More resources here.

Historical projections from many different models (both physics-based dynamical models and statistical models) with actual observations overlaid in black:


Forecasts from various models going out until October of next year:


For a reference on our ability to forecast ENSO, see Chen et al. They reconstruct forecasts using the LDEO model going back more than a century:

Time series of SST anomalies averaged in the NINO3.4 region (5° S–5° N, 120–170° W). The red curve is monthly analysis of [reconstructed observations] and the blue curve is the LDEO5 prediction at 6-month lead. Source: Nature.

and show, somewhat incredibly, that strong El Nino events can be reasonably forecast (corr ~ 0.75) up to twenty months in advance:


These are shown as a function of start month and lead. The straight green lines denote the verification month of May. The left panel is based on all monthly anomalies, while the right panel is for anomalies with amplitudes greater than 0.7 °C. The colour bar shows the range of correlation coefficients. Source: Nature.

12.19.2011

I know unsustainable development when I see it

People frequently ask "What is sustainable development?"  That's a hard question to answer well at a cocktail party.  But the reverse is much easier to handle: "What is unsustainable development?"  Stealing from Justice Potter Stewart's definition of pornography, I can confidently say "I know it when I see it."  Here are two interesting examples that I recently found in the literature.

Buffalo Hunt: International Trade and the Virtual Extinction of the North American Bison
M. Scott Taylor
Abstract: In the sixteenth century, North America contained 25 to 30 million buffalo; by the late nineteenth century fewer than 100 remained. While removing the buffalo east of the Mississippi took over 100 years, the remaining 10 to 15 million buffalo on the Great Plains were killed in a punctuated slaughter lasting little more than ten years. I employ theory, international trade statistics, and first-per- son accounts to argue the slaughter was initiated by a foreign-made innovation and fueled by a foreign demand for industrial leather. European demand and American policy failure are jointly responsible for the “Slaughter on the Plains.”
(h/t Ram)


ON THE COLLAPSE OF HISTORICAL CIVILIZATIONS 
DAVID H. GOOD AND RAFAEL REUVENY
To explain the collapse of historical civilizations, scholars typically point to suboptimal behaviors including misunderstanding the natural environment, shortsightedness, or a lack of institutions. We examine the collapse of four historical societies with a model of endogenous population growth and renewable resources employing components of optimal resource management, economic growth theory, and the moral philosophy of social welfare function choice. We find that these collapses may have been socially optimal. Further, we show that the transient behavior of the system is more sensitive to assumptions than the equilibrium behavior and that focusing solely on equilibria may miss key insights.
[a related but different view is here]

12.12.2011

Fukushima's long-term implications

Two articles came out in PNAS Environmental Sciences this week estimating the fallout from the Fukushima nuclear disaster (Yasunari et al. and Kinoshita et al.). Of particular concern is the following from Yasunari et al.:
As a general characteristic, most of the eastern parts of Japan were effected by a total 137 Cs deposition of more than 1,000 MBq km−2 . Our estimates show that the area around NPP in Fukushima, secondarily effected areas (Miyagi and Ibaraki prefectures), and other effected areas (Iwate, Yamagata, Tochigi, and Chiba prefectures) had 137 Cs depositions of more than 100,000, 25,000, and 10,000 MBq km−2 , respectively. Airborne and ground-based survey measurements jointly carried out by MEXT and the US Department of Energy (DOE) (21) show high 137 Cs deposition amounts were observed northwestward and up to a distance of 80 km from Fukushima NPP. It was estimated from the first measurement that by April 29, more than 600,000 MBq km−2 had been deposited in the area, which is greater than our estimate of less than 500,000 MBq km−2 (Fig. 2A), yet well within the range of uncertainty of our method (Fig. S4).
1,000 MBq (megabecquerels) per square kilometer is 1 kilobecquerel per square meter, so the three broad exposure estimates correspond to 100, 25, and 10 kBq m-2, with maximum treatments around 500-600 kBq m-2. To answer how worried we should be about this, we turn to Almond, Edlund, and Palme, 2009:
We use prenatal exposure to Chernobyl fallout in Sweden as a natural experiment inducing variation in cognitive ability. Students born in regions of Sweden with higher fallout performed worse in secondary school, in mathematics in particular. Damage is accentuated within families (i.e., siblings comparison) and among children born to parents with low education. In contrast, we detect no corresponding damage to health outcomes. To the extent that parents responded to the cognitive endowment, we infer that parental investments reinforced the initial Chernobyl damage. From a public health perspective, our findings suggest that cognitive ability is compromised at radiation doses currently considered harmless.
The heaviest fallout in Sweden (also due to Cesium 137 contamination) was around 65 kBq m-2 (see figure 2 of the paper). Moreover Japan's population density is roughly an order of magnitude larger than Sweden's. Given this, it looks like the long term human costs of this disaster may be absolutely staggering.

12.09.2011

Who self-identifies as a sustainability scientist?


The footprint of sustainability science in terms of traditional scientific disciplines. (A) The percent distribution in terms of ISI disciplines determined based on the classification of journals where publications appeared. The field receives its largest contribution (about 34%) from the social sciences, and other large contributions from biology and chemical, mechanical and civil engineering. Other important contributors are from medicine, Earth sciences, and infectious diseases. A similar analysis for sustainable development shows the same patterns with only a small 5% increase in the relative contribution of the social sciences vs. biology. Copyright PNAS.
Geographic distribution of sustainability science publications. (A) National counts of number of publications. (B) National counts for number of citations received. Fig. S4 shows the analogous map for number of citations per paper. The maps show the wide geographic distribution of the field of sustainability science. This is unusual as compared to typical specialized fields in the natural sciences, for example, and notably demonstrates the quality and quantity of contributions from many developing nations. Note the strength of smaller nations such as Australia, the United Kingdom, the Netherlands, Sweden, South Africa, Kenya, and of Brazil and China. Copyright PNAS.



Cool google earth visualization here. Related post here.  The paper (open access):
Evolution and structure of sustainability science 
Luís M. A. Bettencourta and Jasleen Kaur
Abstract: The concepts of sustainable development have experienced extraordinary success since their advent in the 1980s. They are now an integral part of the agenda of governments and corporations, and their goals have become central to the mission of research laboratories and universities worldwide. However, it remains unclear how far the field has progressed as a scientific discipline, especially given its ambitious agenda of integrating theory, applied science, and policy, making it relevant for development globally and generating a new interdisciplinary synthesis across fields. To address these questions, we assembled a corpus of scholarly publications in the field and analyzed its temporal evolution, geographic distribution, disciplinary composition, and collaboration structure. We show that sustainability science has been growing explosively since the late 1980s when foundational publications in the field increased its pull on new authors and intensified their interactions. The field has an unusual geographic footprint combining contributions and connecting through collaboration cities and nations at very different levels of development. Its decomposition into traditional disciplines reveals its emphasis on the management of human, social, and ecological systems seen primarily from an engineering and policy perspective. Finally, we show that the integration of these perspectives has created a new field only in recent years as judged by the emergence of a giant component of scientific collaboration. These developments demonstrate the existence of a growing scientific field of sustainability science as an unusual, inclusive and ubiquitous scientific practice and bode well for its continued impact and longevity. 

12.08.2011

Political implications of perceived agreement on climate change

Support for climate policy and societal action are linked to perceptions about scientific agreement
Ding Ding, Edward W. Maibach, Xiaoquan Zhao, Connie Roser-Renouf & Anthony Leiserowitz
Abstract: Although a majority of US citizens think that the president and Congress should address global warming, only a minority think it should be a high priority. Previous research has shown that four key beliefs about climate change—that it is real, human caused, serious and solvable—are important predictors of support for climate policies. Other research has shown that organized opponents of climate legislation have sought to undermine public support by instilling the belief that there is widespread disagreement among climate scientists about these points—a view shown to be widely held by the public. Here we examine if this misperception is consequential. We show that the misperception is strongly associated with reduced levels of policy support and injunctive beliefs (that is, beliefs that action should be taken to mitigate global warming). The relationship is mediated by the four previously identified key beliefs about climate change, especially people’s certainty that global warming is occurring. In short, people who believe that scientists disagree on global warming tend to feel less certain that global warming is occurring, and show less support for climate policy. This suggests the potential importance of correcting the widely held public misperception about lack of scientific agreement on global warming.
I suppose this is more rational than this, but that's not saying much...

12.02.2011

Conflict News

A new paper finds evidence to support the "rapacity" or "prize" mechanism as an important factor driving civil conflict.

The Peace Research Institute of Oslo has released a gridded version of it's conflict dataset PRIO-GRID 1.0 (h/t Kyle)

The Office of the Under Secretary of Defense released a report on Trends and Implications of Climate Change for National and International Security, including recommendations for next steps.

12.01.2011

Sprawl

Here's a fun 2006 QJE paper that recently ran into. I especially like that they authors made a free down-loadable poster to go along with the paper!

CAUSES OF SPRAWL: A PORTRAIT FROM SPACE
MARCY BURCHFIELD, HENRY G. OVERMAN, DIEGO PUGA, MATTHEW A. TURNER

Abstract: We study the extent to which U. S. urban development is sprawling and what determines differences in sprawl across space. Using remote-sensing data to track the evolution of land use on a grid of 8.7 billion 30 30 meter cells, we measure sprawl as the amount of undeveloped land surrounding an average urban dwelling. The extent of sprawl remained roughly unchanged between 1976 and 1992, although it varied dramatically across metropolitan areas. Ground water availability, temperate climate, rugged terrain, decentralized employment, early public transport infrastructure, uncertainty about metropolitan growth, and unincorporated land in the urban fringe all increase sprawl.


11.29.2011

Are we producing negative wealth?

Environmental Accounting for Pollution in the United States Economy
Nicholas Z. Muller, Robert Mendelsohn and William Nordhaus

Abstract: This study presents a framework to include environmental externalities into a system of national accounts. The paper estimates the air pollution damages for each industry in the United States. An integrated-assessment model quantifies the marginal damages of air pollution emissions for the US which are multiplied times the quantity of emissions by industry to compute gross damages. Solid waste combustion, sewage treatment, stone quarrying, marinas, and oil and coal-fired power plants have air pollution damages larger than their value added. The largest industrial contributor to external costs is coal-fired electric generation, whose damages range from 0.8 to 5.6 times value added.

11.28.2011

Sense and Sustainability

I recently "discovered" a great podcast: Sense and Sustainability.  Impressively, it's run by Jisung Park, a PhD student at Harvard econ, along with his colleagues (clearly none of them have reached the dissertation-writing-panic-stage of their respective programs). Check it out.

Sense and Sustainability is a production devoted to exploring the diversity of perspectives on issues of sustainable development. This semi-weekly podcast features guests from a range of disciplines, in an attempt to provide a more holistic sense of what we mean by ”sustainability”. We seek to provide a forum for educated yet accessible, incisive yet balanced conversations about a broad range of issues pertaining to global sustainable development. 
You can download episodes from our website www.senseandsustainability.net, or subscribe to the podcast on iTunes (search: “Sense and Sustainability”). 
Sense and Sustainability is a collaborative effort with Consilience: The Journal of Sustainable Development at Columbia University.

11.26.2011

Weekend Links

1) Madden Julian Conversation: A blog by a small group of climate scientists about the Madden-Julian Oscillation and the DYNAMO field campaign in the Indian Ocean.

2) trefis.com will do your stock price event studies for you. I wonder if "coups" or "corruption" ever show up as a line item.... (h/t Mina)














3) Earth | Time Lapse View from Space, Fly Over | NASA, ISS from Michael König (h/t Ram)




4) Teaching yourself to be a good seminar participant can have negative externalities.

5) NASA is looking for potential astronauts

11.24.2011

Math studying = f(weather)

At MIT we used to joke that the earth science department turned on the "weather machine" on the days when prospective students were visiting and trying to decide whether to enroll (since the weather always seemed to be perfect).  But maybe the admissions department got a sign mixed up when then told EAPS what kind of weather they wanted.

More seriously, this may be important for explaining labor supply responses to the weather.

Weather to go to college
Uri Simonsohn

Abstract: Does current utility bias predictions of future utility for high stakes decisions? Here I provide field evidence consistent with such Projection Bias in one of life’s most thought-about decisions: college enrolment. After arguing and documenting with survey evidence that cloudiness increases the appeal of academic activities, I analyse the enrolment decisions of 1,284 prospective students who visited a university known for its academic strengths and recreational weaknesses. Consistent with the notion that current weather conditions influence decisions about future academic activities, I find that an increase in cloudcover of one standard deviation on the day of the visit is associated with an increase in the probability of enrolment of 9 percentage points.


11.22.2011

Child labor and empirical development

Sol and I each recently come across empirical papers on child labor which, at least at first glance, seem to arrive at rather different conclusions. The first, by Eric Edmonds and Norbert Schady, finds that cash transfers to poor women in Ecuador decrease child labor rates (h/t Chris Blattman):
Poor women with children in Ecuador were selected at random for a cash transfer equivalent to 7 percent of monthly expenditures. The transfer is greater than the increase in schooling costs at the end of primary school, but it is less than 20 percent of median child labor earnings in the labor market. Poor families with children in school at the time of the award use the extra income to postpone the child’s entry into the labor force. Students in families induced to take-up the cash transfer by the experiment reduce their involvement in paid employment by 78 percent and unpaid economic activity inside their home by 32 percent.
The second is by Leah Nelson and shows that medium term credit for poor Thai families increases child labor rates:
This paper seeks to understand household business decisions in response to increased credit access in an environment with multiple market failures. A simple model suggests that households at certain wealth thresholds might be able to overcome the fi xed costs of entering entrepreneurship when they have increased access to credit. In the presence of labor market imperfections however, these same households may also be more likely to employ child labor. I test these predictions using household and child level panel data from Thailand. To isolate the causal impacts of household borrowing, I exploit the exogenous timing and institutional features of the Million Baht Program, one of the largest government initiatives to increase household access to credit in the world. I find that, consistent with the model, expanded access to credit raises entry into entrepreneurship for households in specific wealth groups while simultaneously increasing the use of child labor in these households. The results suggest that through the avenue of encouraging entrepreneurial activity, expanding credit access may have unintended consequences for the supply of child labor.
So at least according to these two studies there's a fairly substantial difference between simply providing money and providing credit that requires a productive return over a short horizon. That may seem obvious ex-post, but I think it'd be hard to predict without actually running the empirics and seeing how they shake out. Or, put differently: ever more and better empirical work provides ever better and more nuanced policy implications.

11.21.2011

Orbital forcing, the green Sahara, human migration and the rise of civilization in the Nile Valley

In a recent talk, Peter B. deMenocal was showing results from this 2006 paper in Science. If you're interested in this stuff, I also recommend looking at Peter's work.  [More paleo-climate/social papers here.]

Climate-Controlled Holocene Occupation in the Sahara: Motor of Africa’s Evolution
Rudolph Kuper and Stefan Kropelin

Abstract: Radiocarbon data from 150 archaeological excavations in the now hyper-arid Eastern Sahara of Egypt, Sudan, Libya, and Chad reveal close links between climatic variations and prehistoric occupation during the past 12,000 years. Synoptic multiple-indicator views for major time slices demonstrate the transition from initial settlement after the sudden onset of humid conditions at 8500 B.C.E. to the exodus resulting from gradual desiccation since 5300 B.C.E. Southward shifting of the desert margin helped trigger the emergence of pharaonic civilization along the Nile, influenced the spread of pastoralism throughout the continent, and affects sub-Saharan Africa to the present day.


In some of my work with colleagues (notably Jesse), we've been finding evidence that it's very costly for populations to adapt to their climate, even in the long run (see herehere, here, and here).  This implies that populations may will endure large welfare losses to the climate without employing adaptation (eg. migrating away).  What I find interesting about the figure above is that even after an abrupt drying event, it takes populations ~1000 years to completely abandon a location.  Presumably, over the course of that millenium, the abruptly dried climate exacted a substantial welfare toll on the population.  I think this general idea has real implications for how we think about human responses to climatic changes. In general, it's assumed that adaptation is relatively cheap so that we adjust quickly to reduce welfare losses to the climate.  However, if the costs of adaptation are high, the adjustments will be slow and the welfare losses will be large. (A more detailed discussion is in this paper.)

11.16.2011

We should rename this the Temperature Blog

When I first showed these results to people, more than one of my senior colleagues said "It can't be true, you made a mistake."  But now that business faculty are working on the problem, I might be willing to declare that we have reached stage two of acceptance.

Severe Weather and Automobile Assembly Productivity

Gérard P. Cachon, Santiago Gallino and Marcelo Olivares


Abstract: It is expected that climate change could lead to an increased frequency of severe weather. In turn, severe weather intuitively should hamper the productivity of work that occurs outside. But what is the effect of rain, snow, fog, heat and wind on work that occurs indoors, such as the production of automobiles? Using weekly production data from 64 automobile plants in the United States over a ten-year period, we find that adverse weather conditions lead to a significant reduction in production. For example, one additional day of high wind advisory by the National Weather Service (i.e., maximum winds generally in excess of 44 miles per hour) reduces production by 26%, which is comparable in order of magnitude to the estimated productivity drop during the launch of a new vehicle. Furthermore, the location with the best weather (Arlington, Texas) only loses 2% of production per year due to the weather, whereas the location with the most adverse weather (Lordstown, OH) suffers an annual production loss of 11%. Our findings are useful both for assessing the potential aggregate productivity shock associated with inclement weather as well as guiding managers on where to locate a new production facility - in addition to the traditional factors considered in plant location (e.g., labor costs, local regulations, proximity to customers, access to suppliers), we add the prevalence of bad weather.



Welfare Costs of Long-Run Temperature Shifts
Ravi Bansal, Marcelo Ochoa

Abstract: This article makes a contribution towards understanding the impact of temperature fluctuations on the economy and financial markets.  We present a long-run risks model with temperature related natural disasters.  The model simultaneously matches observed temperature and consumption growth dynamics, and key features of financial markets data.  We use this model to evaluate the role of temperature in determining asset prices, and to compute utility-based welfare costs as well as dollar costs of insuring against temperature fluctuations. We find that the temperature related utility-costs are about 0.78% of consumption, and the total dollar costs of completely insuring against temperature variation are 2.46% of world GDP.  If we allow for temperature-triggered natural disasters to impact growth, insuring against temperature variation raise to 5.47% of world GDP. We show that the same features, long-run risks and recursive-preferences, that account for the risk-free rate and the equity premium puzzles also imply that temperature-related economic costs are important.  Our model implies that a rise in global temperature lowers equity valuations and raises risk premiums.

Temperature, Aggregate Risk, and Expected Returns
Ravi Bansal, Marcelo Ochoa

Abstract: In this paper we show that temperature is an aggregate risk factor that adversely affects economic growth.  Our argument is based on evidence from global capital markets which shows that the covariance between country equity returns and temperature (i.e., temperature betas) contains sharp information about the cross-country risk premium; countries closer to the Equator carry a positive temperature risk premium which decreases as one moves farther away from the Equator.  The differences in temperature betas mirror exposures to aggregate growth rate risk, which we show is negatively impacted by temperature shocks.  That is, portfolios with larger exposure to risk from aggregate growth also have larger temperature betas; hence, a larger risk premium.  We further show that increases in global temperature have a negative impact on economic growth in countries closer to the Equator, while its impact is negligible in countries at high latitudes.  Consistent with this evidence, we show that there is a parallel between a country's distance to the Equator and the economy's dependence on climate sensitive sectors; in countries closer to the Equator industries with a high exposure to temperature are more prevalent.  We provide a Long-Run Risks based model that quantitatively accounts for cross-sectional differences in temperature betas, its link to expected returns, and the connection between aggregate growth and temperature risks.



More related material here.

11.14.2011

The Atlas of Economic Complexity

Chris Blattman points us to a new development econ data set / project / methodology : The Atlas of Economic Complexity. From Ben Ramalingam's interview with Cesar Hidalgo:
As readers will be well aware, the social accumulation of productive knowledge has not been universal: “The enormous income gaps between rich and poor nations are an expression of the vast differences in productive knowledge amassed by different nations.” 
These differences are expressed in the diversity and sophistication of the things that each nation makes. In order to put knowledge into productive use, societies need to reassemble these distributed products through teams, organisations and markets. These issues are explored in detail in the Atlas, through the concept of the ‘product space’. This is a map which captures the products made by different countries in terms of their knowledge requirements 
....
Hausmann, Hidalgo and their team have also developed an Index of Economic Complexity to represent their data systematically. This Index tells us about the richness of the product space of a given country, and by extension, is one useful indicator of the potential to grow.

In effect they're taking applied network techniques for measuring network density and size and using them to infer summary statistics about the complexity of a nation's economic production. It's a pretty interesting idea, particularly since they can do it for time series data and make arguments about growth:

Hausmann and Hidalgo give their  take on this by comparing the Economic Complexity Index for Ghana and Thailand. The lessons are resonant for aid agencies. Both countries had similar levels of schooling in 1970, and Ghana expanded education more vigorously than Thailand in the subsequent 40 years, supported of course by external assistance and policy recommendations. 
Despite this, “Ghana’s economic complexity and income stagnated as it remained an exporter of cocoa, aluminium, fish and forest products. By contrast, between 1970 and 1985 Thailand underwent a massive increase in economic complexity, equivalent to a change of one standard deviation in the Economic Complexity Index. This caused a sustained economic boom in Thailand after 1985. As a consequence, the level of income per capita between Ghana and Thailand has since diverged dramatically.” 
The Economic Complexity Index has been shown to be a better predictor of economic growth than a number of other existing development indicators. For example, as reported in the Economist last week, it outstrips the WEF index of competitiveness by a factor of 10 in terms of the accuracy of its predictions. It also outperforms the World Governance Indicators and the standard variable used to measure human capital as predictors of growth.

All in all fascinating. The site for the atlas is here. Go play around.

11.13.2011

Empirical evidence that hard work can make the world a better place

Sometimes when it's the weekend and you need a motivational break from furiously analyzing-data-while-writing-two-papers-while-applying-for-jobs-while-refereeing-stuff-and-washing-dishes, a movie on a historical success does the trick.  Here are some of my favorites flavors of inspiration-caffeine [despite their historical inaccuracies...]:

Amazing Grace - ending slavery in the British Empire
(one of my favorite quotes is Edmund Burke on these events)

Ghandhi - liberating India and Pakistan

The Great Debaters - civil rights in the US
(maybe I like this because I met my fiance on our high-school's science olympiad team...)

Invictus - reconciliation in post-apartheid South Africa
(I remembered to post this because I was jogging in my Springbok's jersey!)

11.12.2011

Jobs in sustainability

Several of my colleagues are now looking for jobs in sustainability.  Ram points us in the direction of this impressive database hosted by Duke (notably heavy in biological fields).

Searching NatureJobs for "sustainable" also brings up 134 positions at the time of posting.  Also see job listings at the Association of Environmental and Resource Economists.  Environmental economists can also see this page at Michigan State.

If you know of more listings, please post a comment.  Maybe we'll assemble a database if we find enough.

11.09.2011

How do I find climate data for my research?

Once every three weeks a colleague (usually in the social sciences) emails me to ask about whether a climate data set of type X exists or what the pros/cons of various datasets are. I'm always happy to help, but it's useful to  know that there are multiple websites that maintain collections of various kinds of climate/global environment data, and several have pages that specifically compare the array of data sets out there.  If you're looking for data, a few clicks through these sites will give you a good sense of what's available.

All of these sites are listed in our meta-resources page.

11.08.2011

Open access textbooks

Want to increase access to tertiary education but don't have lots of cash on hand for increasing your stock of educational materials? I recently met with the CTO of boundlessnow.com and they have an elegant solution to this problem: organize pre-existing open source content (eg. wikipedia) into textbook form and make access to students free.

As a bonus, the textbooks are organized to reflect the structure of pre-existing textbooks, so students unable to afford expensive textbooks can read the same material that their professor assigns to the rest of the class.  But I can imagine professors [particularly in low/middle-income, but highly-networked, countries] simply assigning the Boundless version of the textbook rather than bothering with lip-service to the original publication.

Some impressive points from their FAQs

How are Boundless Textbooks Made?Boundless Textbooks are created in a 3-step process:
  • We curate the highest quality open source educational content and vet it with our team of top educational professionals from Harvard, MIT, Columbia, UC Berkeley, and other top institutions.
  • We serve the open source educational content to cover the same material and concepts you are covering in your class and assignments.
  • We make your Boundless Textbook digitally available from any computer at anytime and integrate the ability to instantly share notes, highlights and more with classmates and friends. 
Do Boundless textbooks cost any money?No. Boundless Textbooks are 100% free. 
How long do I get access to Boundless Books?You get universal access to your Boundless textbooks for life. There are no rental periods or other limitations. 
How are the books free?Over the past 15 years, leading individuals and institutions, including MIT, Rice, Yale, and others, have begun releasing high quality educational content for others to use. This content is know as “Open Educational Resources (OER)”. 
Recently, various state governments and the US government have begun investing Billions of dollars to continue creating more high quality open content (yes, that’s Billions with a B). 
The Boundless Team organizes, edits and improves this content so that students can access the exact material that they need, whenever they need it.

Coupled to projects like OLPC, efforts like this could have big impacts on primary and secondary education as well.

11.06.2011

Islam, Peace, and the Hajj

This morning I stumbled across a favorite applied micro paper from a few years back that's particularly relevant today: Clingingsmith, Khwaja and Kremer's 2009 Estimating the Impact of The Hajj: Religion and Tolerance in Islam's Global Gathering in the Quarterly Journal of Economics*. The abstract speaks for itself:
We estimate the impact on pilgrims of performing the Hajj pilgrimage to Mecca. Our method compares successful and unsuccessful applicants in a lottery used by Pakistan to allocate Hajj visas. Pilgrim accounts stress that the Hajj leads to a feeling of unity with fellow Muslims, but outsiders have sometimes feared that this could be accompanied by antipathy toward non-Muslims. We find that participation in the Hajj increases observance of global Islamic practices, such as prayer and fasting, while decreasing participation in localized practices and beliefs, such as the use of amulets and dowry. It increases belief in equality and harmony among ethnic groups and Islamic sects and leads to more favorable attitudes toward women, including greater acceptance of female education and employment. Increased unity within the Islamic world is not accompanied by antipathy toward non-Muslims. Instead, Hajjis show increased belief in peace, and in equality and harmony among adherents of different religions. The evidence suggests that these changes are likely due to exposure to and interaction with Hajjis from around the world, rather than to a changed social role of pilgrims upon return.
Tightly defined identification strategy, great data, and beautiful, encouraging results about human nature. What more could you ask for? Eid mubarak, everyone.

*A non-gated version of the paper is here.

11.04.2011

"On the Absorption and Radiation of Heat by Gaseous Matter"

The Royal Society announced last week that it was permanently opening the archives of the Philosophical Transactions to the public. A lot of attention surrounding the announcement has gone to such gems as Isaac Netwon's first published paper and Ben Franklin's paper on lightning and kites, but it should be noted that the world's oldest journal also saw some of our earliest advances in climate science, particularly by John Tyndall:
Further, I purified the air of the laboratory so well that its absorption was less than unity; the purified air was then conducted through two U-tubes filled with fragments of clean glass moistened with distilled water. Its neutrality when dry proved that all prejudicial substances had been removed from the air; and in passing throuugh the U-tubes it could have contracted nothing save the pure vapour of water. The vapour thus carried into the experimental tube exerted an absorption 90 times as great as that of the air which carried it.
The emphasis is Tyndall's, and the excerpt comes from this article demonstrating water vapor's extraordinary capacity to absorb infrared radiation. Other highlights include papers on refraction (or 'refrangibility' if you like old-timey science), demonstrating thermal transfer at different parts of the spectrum (note the peak in the infrared in table 1), and quantifying the thermal capacity of infrared-absorbing (also known as "greenhouse"; note tables 1 and 2) gases.

All of which is really just to reiterate one of my favorite student / concerned scientist / chatting-about-climate-with-the-skeptical talking points: our understanding of climate's relationship to greenhouse gases is very, very old. Tyndall was showing that "carbonic acid" (CO2) was opaque to infrared in 1862, alongside other such notable gases as NOx and "marsh gas" (methane). That a radical increase in the atmosphere's concentration of these *very* absorptive gases would lead to additional warming is about as elementary of a scientific postulate as can be.

10.31.2011

A picture is worth a thousand lives

Kristof's article
I am a strong proponent of spending time on figures, tables and presentations so that important ideas are communicated clearly and succinctly.  The story of this  internal letter written by Nicholas Kristof to his colleagues at the New York Times is a good example of why.
From: Nicholas Kristof 
Subject: the power of art 
in september i traveled with bill gates to africa to look at his work fighting aids there. while setting the trip up, it emerged that his initial interest in giving pots of money to fight disease had arisen after he and melinda read a two-part series of articles i did on third world disease in January 1997. until then, their plan had been to give money mainly to get countries wired and full of computers. 
bill and melinda recently reread those pieces, and said that it was the second piece in the series, about bad water and diarrhea killing millions of kids a year, that really got them thinking of public health. Great! I was really proud of this impact that my worldwide reporting and 3,500-word article had had. But then bill confessed that actually it wasn't the article itself that had grabbed him so much -- it was the graphic. It was just a two column, inside graphic, very simple, listing third world health problems and how many people they kill. but he remembered it after all those years and said that it was the single thing that got him redirected toward public health. 
No graphic in human history has saved so many lives in africa and asia. 
I'm sending you a copy of the story and graphic by interoffice mail. whoever did the graphic should take a bow. 
nick kristof

The info-graphic/table that got Gates' attention.

Apparently, the letter itself is framed and hanging up in the office of the data graphics group at the NYT. h/t Pam.

10.28.2011

Attributing climate records to climate change

Stefan Rahmstorf (of RealClimate) and Dim Coumou just published a pretty interesting paper in this week's PNAS, in which they claim last summer's Moscow heat wave was 80% likely to have been due to the observed warming trend in the city. There's a great writeup of the paper (including how and why it contradicts an earlier finding claiming that the heat wave was not due to trends; urban heat island fans should check that one out), but what's particularly noteworthy is the methodology by which they claim attribution of the heat wave to the climate trend:
We develop a theoretical approach to quantify the effect of long-term trends on the expected number of extremes in generic time series, using analytical solutions and Monte Carlo simulations. We apply our method to study the effect of warming trends on heat records. We find that the number of record-breaking events increases approximately in proportion to the ratio of warming trend to short-term standard deviation. Short-term variability thus decreases the number of heat extremes, whereas a climatic warming increases it. For extremes exceeding a predefined threshold, the dependence on the warming trend is highly nonlinear. We further find that the sum of warm plus cold extremes increases with any climate change, whether warming or cooling. We estimate that climatic warming has increased the number of new global-mean temperature records expected in the last decade from 0.1 to 2.8. For July temperature in Moscow, we estimate that the local warming trend has increased the number of records expected in the past decade fivefold, which implies an approximate 80% probability that the 2010 July heat record would not have occurred without climate warming.
I'm still mulling over how much I believe the causal claim here, but I really like the technique of modeling record-breaking as a function of the system's state over time. Some other potential applications immediately spring to mind...

10.27.2011

Expert credibility in climate change

While doing a lit review I came across this gem of a paper from last July in PNAS:
Expert credibility in climate change 
Although preliminary estimates from published literature and expert surveys suggest striking agreement among climate scientists on the tenets of anthropogenic climate change (ACC), the American public expresses substantial doubt about both the anthropogenic cause and the level of scientific agreement underpinning ACC. A broad analysis of the climate scientist community itself, the distribution of credibility of dissenting researchers relative to agreeing researchers, and the level of agreement among top climate experts has not been conducted and would inform future ACC discussions. Here, we use an extensive dataset of 1,372 climate researchers and their publication and citation data to show that (i) 97–98% of the climate researchers most actively publishing in the field surveyed here support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers. 
I particularly like the use of independent metrics to verify what my casual observation as a researcher says to be true.

Now, there's clearly potential endogeneity in this system since citation behavior can be strategic (e.g., this new paper in R.E. Stat), and many a scientific discovery has been waylaid by collusive behavior among scientists (see, for example, the rise and fall of radical mastectomies as detailed in Emperor of All Maladies, previously here). That said, the next time someone tells you there's a legitimate scientific debate over whether anthropogenic climate change is occurring, I think you can safely make a "we are the 98%" joke.

10.24.2011

Evidence of a link between migration and malaria


Alan Barreca, Price V. Fishback, and Shawn Kantor 

Abstract: The Agricultural Adjustment Act (AAA) caused a population shift in the United States in the 1930s. Evaluating the effects of the AAA on the incidence of malaria can therefore offer important lessons regarding the broader consequences of demographic changes. Using a quasi-first difference model and a robust set of controls, we find a negative association between AAA expenditures and malaria death rates at the county level. Further, we find the AAA caused relatively low-income groups to migrate from counties with high-risk malaria ecologies. These results suggest that the AAA-induced migration played an important role in the reduction of malaria.


10.21.2011

Increasing income increases deforestation in Mexico

Over a year ago, I pointed readers to this paper after seeing it at WCERE and thinking it was important, so I'm happy to hear that its now forthcoming in ReStat.  It is also is also an excellent example of individuals increasing their resource consumption, when they becoming richer, by increasing their trophic level (described two posts ago).  The paper finds that when households receive cash transfers, they consume more meat, which requires more rangeland, which induces additional deforestation.

Jennifer Alix-Garcia, Craig McIntosh, Jarrod R. Welch, Katharine R. E. Sims 

Abstract: We study the consequences of poverty alleviation programs for environmental degradation. We exploit the community-level eligibility discontinuity for a conditional cash transfer program in Mexico to identify the impacts of income increases on deforestation, and use the program’s initial randomized rollout to explore household responses. We find that additional income raises consumption of land-intensive goods and increases deforestation. The observed production response and deforestation increase are larger in communities with poor road infrastructure. This suggests that better access to markets disperses environmental harm and that the full effects of poverty alleviation can be observed only where poor infrastructure localizes them.


10.20.2011

Consensus building and norm engineering

The New York Times has a fascinating article on a recent radical decline in the prevalence of female genital cutting / mutilation in Senegal:
Across the continent, an estimated 92 million girls and women have undergone [genital cutting]. But like more than 5,000 other Senegalese villages, Sare Harouna has joined a growing movement to end the practice.
The change has not yet reached Ms. Kande’s new home in her husband’s village, but if elders there pressured her to cut the baby girl she is taking into the marriage, she said, “I would resist them.” Her parents back her up.
“They would never dare do that to my granddaughter, and we would never allow it,” said Ms. Kande’s mother, Marietou Diamank.
The movement to end genital cutting is spreading in Senegal at a quickening pace through the very ties of family and ethnicity that used to entrench it. And a practice once seen as an immutable part of a girl’s life in many ethnic groups and African nations is ebbing, though rarely at the pace or with the organized drive found in Senegal. ...
[H]ere in Senegal, Tostan, a group whose name means “breakthrough” in Wolof, Senegal’s dominant language, has had a major impact with an education program that seeks to build consensus, African-style, on the dangers of the practice, while being careful not to denounce it as barbaric as Western activists have been prone to do.
The movement's success is heavily attributed to its inclusivity and consensus building, and the anecdotal evidence in the article seems to back it up. The fact that Tostan's strategy heavily involves griots, traditional story tellers who are somewhere between musician, MC, and radio personalities, seems particularly intuitive and appealing, a bit like trying to get celebrities and athletes in the US to speak out against smoking.

Along those lines, attributing of the program's success to having tailored itself to "African-style" consensus building seems rather small-minded. There are obviously many ways to get people to change their behavior (taxation, accolades, providing information ...), but abolishing genital mutilation seems to be a classic case of changing social norms, and when you think about it, a social norm is nothing more than a codification of expectations over the everyone's behavior. Changing a social norm involves shifting from one equilibrium state of expectations (everyone knows genital cutting is common and necessary and if my daughter doesn't undergo it she and my family will be judged) to another (everyone knows genital cutting is dangerous and unnecessary and if someone asks my daughter to do it they're crazy) for the entire group of individuals. It is, by definition, establishing a consensus. 

I think we can thus say that Tostan's success (to the extent that the success is Tostan's and not attributable to larger demographic forces) lies less in exploiting some native preference for consensus that "Africans" have than in focusing efforts on small clusters of individuals with correlated norms (villages), and then propagating that norm change through the next-closest set of clusters (neighboring / inter-marrying villages). That Tostan works to convince those individuals in an inoffensive way (try convincing anyone, anywhere, to stop doing something because it's 'barbaric') seems necessary but not sufficient to effect that change.