The social and economic impacts of the global climate

We have a new paper out in Science:

Social and Economic Impacts of Climate 

For centuries, thinkers have considered whether and how climatic conditions—such as temperature, rainfall, and violent storms—influence the nature of societies and the performance of economies. A multidisciplinary renaissance of quantitative empirical research is illuminating important linkages in the coupled climate-human system. We highlight key methodological innovations and results describing effects of climate on health, economics, conflict, migration, and demographics. Because of persistent “adaptation gaps,” current climate conditions continue to play a substantial role in shaping modern society, and future climate changes will likely have additional impact. For example, we compute that temperature depresses current U.S. maize yields by ~48%, warming since 1980 elevated conflict risk in Africa by ~11%, and future warming may slow global economic growth rates by ~0.28 percentage points per year. In general, we estimate that the economic and social burden of current climates tends to be comparable in magnitude to the additional projected impact caused by future anthropogenic climate changes. Overall, findings from this literature point to climate as an important influence on the historical evolution of the global economy, they should inform how we respond to modern climatic conditions, and they can guide how we predict the consequences of future climate changes.

Some more of my commentary on the paper is here.

click to enlarge

Access to hardened infrastructure and hurricane mortality

I just happen to be working on a review of hurricane's socio-economic impacts right now, and since there seems to be widespread interest in these things at the moment, I'm just going to post some of the more interesting/important papers as I go. The figure from this 1993 paper is compelling (although I think a brace would be clearer than the arrow).

Risk factors for mortality in the Bangladesh cyclone of 1991
C. Bern, J.Sniezek, G.M. Mathbor, M.S. Sidiqi, C. Ronsmans, A.M.R. Chowdhury, A.E. Choudhury, K. Islam, M. Bennish, E. Noji, & R.l.Glass

Abstract: Cyclones continue to pose a dangerous threat to the coastal populations of Bangladesh, despite improvements in disaster control procedures. After 138 000 persons died in the April 1991 cyclone, we carried out a rapid epidemiological assessment to determine factors associated with cyclone-related mortality and to identify prevention strategies. A nonrandom survey of 45 housing clusters comprising 1123 persons showed that mortality was greatest among under-10-year-olds (26%) and women older than 40 years (31%). Nearly 22% of persons who did not reach a concrete or brick structure died, whereas alpersons who sought refuge in such structures survived. Future cyclone-associated mortality in Bangladesh could be prevented by more effective warnings leading to an earlier response, better access to designated cyclone shelters, and improved preparedness in high-risk communities. In particu- lar, deaths among women and under-10-year-olds could be reduced by ensuring that they are given special attention by families, neighbours, local authorities, and especially those in charge of early warnings and emergency evacuation.

From the results:

Type of housing and shelter-seeking activity were directly related to the risk of dying in the cyclone (Fig. 2). No deaths occurred among the 27 individuals (2%) who lived in pukka houses or remained in pukka public buildings for the duration of the cyclone. However, 1094 individuals (98%) were not in a safe shelter prior to the cyclone warning. In response to the warning, which most respondents reported hearing 3-6 hours prior to the storm surge, only 40 individuals (4%) sought and reached safe shelter.When the flood waters first reached the area 10-60 minutes before the storm surge, 151 persons (13%) were insafeshelter.In all, 385 persons (33%) had reached safe shelter by the moment of impact of the storm surge; none of these persons died In con- trast, of 736 persons at risk, 162 (22%; P < 0.0001) drowned in the flood waters.

Of 736 persons at risk at the time of the cyclone impact, 285 were swept away in the storm surge; of these, 112 (39%) died. Another 179 per- sons were able to float on some object, generally the thatch roof of their house; of these, 27 (15%) died. Mortality was 22% among those who sought high ground to escape the storm surge, and 11% among those who took refuge in trees.

The effect of life expectancy on human capital investments

Limited Life Expectancy, Human Capital and Health Investments: Evidence from Huntington Disease
Emily Oster, Ira Shoulson, E. Ray Dorsey

Abstract: One of the most basic predictions of human capital theory is that life expectancy should impact human capital investment.  Limited exogenous variation in life expectancy makes this difficult to test, especially in the contexts most relevant to the macroeconomic applications.  We estimate the relationship between life expectancy and human capital investments using genetic variation in life expectancy driven by Huntington disease (HD), an inherited degenerative neurological disorder with large impacts on mortality. We compare investment levels for individuals who have ex ante identical risks of HD but learn (through early symptom development or genetic testing) that they do or do not carry the genetic mutation which causes the disease.  We find strong qualitative support: individuals with more limited life expectancy complete less education and less job training.  We estimate the elasticity of demand for college completion with respect to years of life expectancy of 0.40. This figure implies that differences in life expectancy explain about 10% of cross-country  differences in college enrollment.  Finally, we use smoking and cancer screening data to test the corollary that health capital is responsive to life expectancy.

Social Impacts of Climate Change and Climate Variability

We had an excellent session at AGU last week, thanks to everyone who contributed. Here's a video of the talks, which are succinct, interesting and nicely delivered.



U53F : AGU Fall Meeting 2011 from American Geophysical Union on Vimeo.

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.

Evidence of a link between migration and malaria

Agricultural Policy, Migration, and Malaria in the 1930s United States

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.

Energy and temperature are substitutes in the production of health

This week in AEJ Applied:

Climate Change, Mortality, and Adaptation: Evidence from Annual Fluctuations in Weather in the US 
Olivier Deschênes and Michael Greenstone

Abstract: Using random year-to-year variation in temperature, we document the relationship between daily temperatures and annual mortality rates and daily temperatures and annual residential energy consumption. Both relationships exhibit nonlinearities, with significant increases at the extremes of the temperature distribution. The application of these results to "business as usual" climate predictions indicates that by the end of the century climate change will lead to increases of 3 percent in the age-adjusted mortality rate and 11 percent in annual residential energy consumption. These estimates likely overstate the long-run costs, because climate change will unfold gradually allowing individuals to engage in a wider set of adaptations.

More on temperature's substitutes/compliments here and here.

(h/t Michael O)

Which health supplements actually work?

Since we're pretty big on data visualization here on Fight Entropy I thought I'd point out that the guys over at Information is Beautiful have updated their great Snake Oil infographic on nutritional supplements. It does an excellent job of summarizing the current state of research on a fairly sprawling and contentious topic. Go check it out.

Now if they'd only do one on climate phenomena...

Supplying Africa with climate data to fight disease

Climatic suitability for
malaria transmission.
See more here. 

In a Comment to Nature this week, M.C. Thomson et al. make the case that climatological information in Africa is under-supplied to decision-makers, especially in the management of public-health (read it here). They suggest that adequate climate information is in short supply because it is a public good, and the value it will generates is through the improvement of other public goods (such as sanitation).

"Climate information is not readily available, so is rarely incorporated into development decisions. At the same time, few public-health institutions or practitioners are equipped to understand or manage the effects of a changing climate, despite major advances in recent years in alerting the health community to its risks.

A dramatic improvement is needed in the availability of relevant and reliable climate data and services, particularly in Africa, where vulnerability to climate is so high. Information — such as historical observations of temperature, ten-day satellite estimates of rainfall, the predicted start date of the rainy season or the likelihood of extreme temperatures in the coming season — should inform the management of all diseases sensitive to climate. These include: malaria, leishmaniasis, acute respiratory infections, intestinal helminths and diarrhoeal diseases. This information could also contribute to food security by providing, for example, early warning for agricultural and livestock pests and diseases.

The following must be put in place within the next decade: new partnerships between the public-health community and national meteorological agencies, space agencies and researchers; a governance structure that ensures data sharing between public and private agencies; a funding model that builds open-access climate databases; climate scientists focused on the delivery of quality products, tailored to user needs; health professionals trained to demand and use climate information; and evidence of the value of all this, relative to alternative investments in health."

The authors use the example of Kericho, Kenya to make their point clear:

(Blue shading is the number of malaria cases per month)
SOURCES: REF. 7; G. D. SHANKS ET AL. GO.NATURE.COM/CPN7KD

"That it took a decade to establish a robust analysis of climate trends in Kericho, a focus of so much controversy, points to a broader disconnect between those who need climate information and those who produce it. In the 1980s, African meteorological agencies were encouraged to sell their data to raise revenue to maintain their networks of meteorological stations. The agencies' services have understandably prioritized their primary client, the airline industry. Access for non-commercial purposes, including for malaria research, has been constrained by poor collaboration and high data fees, among other factors. 

Instead, funding models are needed that recognize climate data as a resource for development — a classic public good that increases in value the more times the data are used." 

Blindness interventions

This is a pretty inspiring story of field work for children with treatable blindness in India, and neurological research that goes alongside treatments:

http://www.ted.com/talks/pawan_sinha_on_how_brains_learn_to_see.html

and another great story of work in the field on blindness (my classmate Mark Orrs is working with him).

http://adventure.nationalgeographic.com/2009/12/best-of-adventure/geoff-tabin/1