Sustainability Math A Quantitative Literacy and Mathematics Resource for Instructors

The graph here from the American Sociological Review paper Income inequality and Class Divides in Parental Investments by Schneider, Hastigs, and LaBriola (5/21/18) summarizes changes in spending on children by income.

The past 40 years have witnessed historic increases in income inequality in the United States (Piketty and Saez 2003). Over the same period, existing class divides—by household income and by parents’ educational attainment—in how much money parents spend on children and how much time parents spend in childcare have widened considerably (Altintas 2016; Kornrich and Furstenberg 2013; Ramey and Ramey 2010). These increasingly evident class divides in parental investments of time and money spark concern, because parental investment is an important factor in the intergenerational perpetuation of advantage (Downey, von Hippel, and Broh 2004; Potter and Roksa 2013; Waldfogel and Washbrook 2011). If affluent families are increasingly able to transmit their advantages to children, that bodes poorly for an open opportunity structure.

Of course,

We would expect rising income inequality to increase class gaps in parental financial investments in children mechanically if rising income inequality simply means the affluent have more to spend. But, rising income inequality might also widen class gaps in investments in children if it reshapes parents’ preferences for these practices differentially by class.

It is also possible that income inequality is not related to class gaps in parental investment. Indeed, recent work suggests a narrowing of gaps in early achievement by family income, and a narrowing or arrested divergence in some gaps in parenting practices, even as income inequality has continued to rise, raising questions about this often assumed empirical relationship (Kalil et al. 2016; Reardon 2011; Reardon and Portilla 2016).

We empirically investigate these questions.

The paper has interesting charts and data, and worth reading for their conclusions. Also, the supplemental materials include some mathematical modeling.

The new paper, Four decades of Antarctic Ice Sheet mass balance from 1979–2017, by Eric Rignot, et. el (PNAS 1/14/19) states

The total mass loss from Antarctica increased from 40 ± 9 Gt/y in the 11-y time period 1979–1990 to 50 ± 14 Gt/y in 1989–2000, 166 ± 18 Gt/y in 1999–2009, and 252 ± 26 Gt/y in 2009–2017, that is, by a factor 6.

An interesting fact from the paper:

Antarctica contains an ice volume that translates into a sea-level equivalent (SLE) of 57.2 m.

Note: 52.2m is about 188 feet. The graph with caption here is from the paper. The Washington Post has a summary of the paper in the article Ice loss from Antarctica has sextupled since the 1970s, new research finds by Chris Mooney and Brady Dennis (1/14/19) and notes

It takes about 360 billion tons of ice to produce one millimeter of global sea-level rise.

Based on the last two quotes, How much ice is there on Antarctica?  NASA’s Vital Signs of the Planet has Antarctica Ice data on their Ice sheets page.

Related Post: How well do we understand rising sea levels?

The first two interactive graph have been posted at sustainabilitymath.org.  They can be found at the new Interactive Graphs page. The two graph represent mean and median wages by race and gender with regression lines from 1973 to 2017 (data from EPI).  Check them out because they are interesting and both could be used in a QL or stats course.

According to the EIA article U.S. coal consumption in 2018 expected to be the lowest in 39 years:

EIA expects total U.S. coal consumption in 2018 to fall to 691 million short tons (MMst), a 4% decline from 2017 and the lowest level since 1979. U.S. coal consumption has been falling since its peak in 2007, and EIA forecasts that 2018 coal consumption will be 437 MMst (44%) lower than 2007 levels, mainly driven by declines in coal use in the electric power sector.

Why the decline?

One of the main drivers of coal retirements is the price of coal relative to natural gas. Natural gas prices have stayed relatively low since domestic natural gas production began to grow in 2007. This period of sustained, low natural gas prices has kept the cost of generating electricity with natural gas competitive with generation from coal. Other factors such as the age of generators, changes in regional electricity demand, and increased competition from renewables have led to decreasing coal capacity.

EIA coal consumption data can be found on the Monthly Energy Review page and in our Calculus Projects page.  A recent Think Progress article,
More coal plants shut down in Trump’s first two years than in Obama’s entire first term – The administration’s own data reveal coal isn’t coming back by Joe Romm (1/3/19) reports on the decrease in coal consumption.

The Royal Society research article, The broiler chicken as a signal of human reconfigured biosphere by Carys E. Bennett et. el. (12/12/18) , provides the evidence of how human intervention has changed a species.

Breeding by natural selection has been modified by human-directed selection. While the size of the domesticated chicken in historical times was little different to the red jungle fowl (figure 3), domestic chicken bone morphology shows that selective breeding practices took place as early as the sixteenth century [53,54]. Chickens from the late twentieth century are markedly different in terms of size (figures 3 and 4), growth rate (figure 5) and body shape. The change in body mass and body shape has been visually documented by photographs of broiler breeds throughout ontogeny from 1957, 1978 and 2005 [14]. Broilers from a 1957 breed are between one-fourth and one-fifth of the body weight of broilers from a twenty-first century breed [13,14]. The modern broiler is a distinctive new morphotype with a relatively wide body shape, a low centre of gravity [13] and multiple osteo-pathologies. If left to live to maturity, broilers are unlikely to survive. In one study, increasing their slaughter age from five weeks to nine weeks resulted in a sevenfold increase in mortality rate [55]: the rapid growth of leg and breast muscle tissue leads to a relative decrease in the size of other organs such as the heart and lungs, which restricts their function and thus longevity [56]. Changes in the centre of gravity of the body, reduced pelvic limb muscle mass and increased pectoral muscle mass cause poor locomotion and frequent lameness [15]. Unlike most other neobiota, this new broiler morphotype is shaped by, and unable to live without, intensive human intervention.

The article includes a number of interesting charts including the one copied here and in reference to the figure they refer to a derivative:

Chicken-meat consumption is growing faster than any other meat type and is soon to outpace pork

Data used in the paper is available under Supplemental Material (left side bar).

The Pew article, A record number of women will be serving in the new Congress by Drew Desliver (12/18/18) provides an historical overview and the chart copied here of women in congress.

When the 116th Congress convenes next month, women will make up nearly a quarter of its voting membership – the highest percentage in U.S. history, and a considerable increase from where things stood not too long ago.

A record 102 women will serve in the incoming House of Representatives, comprising 23.4% of the chamber’s voting members. More than a third of those women (35) won their seats for the first time in last month’s midterms.

The differences by party are notable. For instance, the most Republican women in the House of Representative was 25 in 2017-2019 and down to  13 this year.  On the other hand, there have been more than 25  Democrat women in the House since the 1993-1995 congress. As a percentage of each party’s delegation, women have never exceeded more than 10% of Republican House members. From 109th through 112th congress (2005-2013) women made up 9.9% of Republican House members. This is down to 6.5% (13 women) this year. On the other hand, women have been generally increasing as a percentage of Democrat House members since the 101st congress (1989-1991) and stand at 38% (89 women) this year.  Wikipedia posts this data in a table, which comes from a Congressional Research Service report.

Related post: World Development Indicators: Proportion of seats held by women in national parliaments (3/2/17)

Thanks to all the visitors of sustainabilitymath.org.  Have a Happy New Year! In 2019 the goal is to continue to post sources of graph and data while adding some of our own interactive graphs to the site.

EPI puts forth its top twelve charts of 2018 in the post Top charts of 2018 Twelve charts that show how policy could reduce inequality—but is making it worse instead (12/20/2018). For example,  chart 10 (copied here) compares 11 economic and social indicators between white and African american families from 1968 to 2018.

Not nearly far enough. The chart shows that, while African Americans are in many ways better off in absolute terms than they were in 1968, they are still disadvantaged in important ways relative to whites. African Americans today are much better educated than they were in 1968—but young African Americans are still half as likely as young whites to have a college degree. Black college graduation rates have doubled—but black workers still earn only 82.5 cents for every dollar earned by white workers. And—as consequences of decades of discrimination—African American families continue to lag far behind white families in homeownership rates and household wealth. The data reinforce that our nation still has a long way to go in a quest for economic and racial justice.

There are 11 other economic related charts. Each chart has a link to data and can  be downloaded.

The graph here is produced from data made available at the Conversation article ‘Tis the season for conception by Micaela Martinez and Kevin M. Bakker (12/19/18). Is there a pattern that is similar for both New York and Texas? It sure seems like it.

It turns out reproduction is seasonal across all living organisms, from plants, to insects, to reptiles, to birds and mammals – including human beings. The ultimate explanation for this phenomenon is an evolutionary one.

Earth’s environment is seasonal. Above or below the equator, the year is structured by the winter, spring, summer and fall. In equatorial regions, the wet and dry seasons punctuate the year. Organisms have evolved strategies to reproduce at the time of year that will maximize their lifetime reproductive success.

Humans are no exception and maintain this evolutionary outcome: birth seasonality. Researchers, including us, have recently been working to understand more about why births are seasonal because these patterns can have a big impact on childhood disease outbreaks.

The article has another graph, also with data. The R-script and csv file for the graph here.

In 2016 clinker contributed almost 2 billion tonnes of CO2, about 7% of the world total. What is clinker? The BBC article Climate change: The massive CO2 emitter you may not know about by Lucy Rodgers (12/17018) provides the answer. In short, clinker is the key ingredient in cement and the world produces a lot of cement (see graph). 

Cement is the source of about 8% of the world’s carbon dioxide (CO2) emissions,according to think tank Chatham House.

If the cement industry were a country, it would be the third largest emitter in the world – behind China and the US. It contributes more CO2 than aviation fuel (2.5%) and is not far behind the global agriculture business (12%).

Clinker accounts for about 90% of the CO2 emissions related to concrete and so 90% of the 8% of world CO2 from cement is due to clinker.  Historical data for world cement production can be found on the USGS page  Historical Statistics for Mineral and Material Commodities in the United States. For the last couple of years see the Cement Statistics can Information page.  The BBC article has another a couple of other nice graphs and a diagram with an explanation of how cement is made.