How did minimum wage increases impact wage growth?

This graph from the EPI post Low-wage workers saw the biggest wage growth in sates that increased their minimum wage between 2018 and 2019 by Elise Gould (3/4/2020) answers part of the question. It is worth noting that:

Strong wage growth at the 10th percentile is not simply due to stronger overall wage growth in those states.

Between 2018 and 2019, the median and 80th percentile wage in states with minimum wage changes increased 0.7% and 1.5%, respectively, while they increased 2.1% and 2.4%, respectively, in non-changing states.

There are three other graphs in the article and each has a link to data.

What’s New at sustainabilitymath?

In a follow up to last week’s graph, I have added a demographic graph of New York State, which provides the number of students in each grade in the 2017-2018 school year by race. The hover information includes percentages for each group. The data comes from the National Center for Education Statistics Elementary/Secondary Information System (ELSi). The link will take you to various table generators and it is easy enough to get data for your state and even data at the district level is available.

Isn’t the sun causing global warming?

No, as can be easily seen by the graphic here copied from the NASA article There is No Impending ‘Mini Ice Age’ (2/13/2020). At the same time we won’t be seeing an ice age anytime soon:

This is called a “Grand Solar Minimum,” and the last time this happened, it coincided with a period called the “Little Ice Age” (a period of extremely low solar activity from approximately AD 1650 to 1715 in the Northern Hemisphere, when a combination of cooling from volcanic aerosols and low solar activity produced lower surface temperatures).

Even if a Grand Solar Minimum were to last a century, global temperatures would continue to warm. Because more factors than just variations in the Sun’s output change global temperatures on Earth, the most dominant of those today being the warming coming from human-induced greenhouse gas emissions.

The article has another time series of solar irradiance with a source.

How much has spring snow cover changed?

This graph shows average area covered by snow in the Northern Hemisphere during March and April as the difference from the 1981-2010 average.

The article Climate Change: Spring Snow Cover by LuAnn Dahlman and Rebecca Lindsey (2/14/2020) provides the answer as seen in their graph here.

This change is another example of a feedback loop.

About one-third of Earth’s land surface is covered by snow for some part of the year. The bright white covering affects global conditions by reflecting solar energy away from surfaces that would otherwise absorb it. Therefore, the earlier decrease in snow cover increases the amount of sunlight absorbed by Earth, and in turn, surface temperatures.

The article includes the data for the graph shown here.

Who is in high-poverty schools?

The EPI article Schools are still segregated, and black children are paying a price by Emma García (2/12/2020) provides an overview of inequities in secondary schools. Figure B in the article is copied here and speaks clearly to issues of inequality by race. There is also a political perspective that the percentages hide. According to Table 2 on the Census Bureau page School Enrollment in the United States: October 2018 – Detailed tables, there were 1,214,00 13 and 14 year old black students and 6,058,000 white students. (Note 13 and 14 years of age is approximately 8th grade and the Census Bureau is 2018 data while the EPI graph here is 2017. ) What this means is that there are 1,214,000*0.724=878,936 black eighth graders in high-poverty schools and 6,058,000*0.313=1,896,154 white eighth graders in high-poverty schools, or over twice as many white student in high-poverty schools.

The EPI article has a total of four graphs with available data.

How do U.S. adults view the economy?

The Pew report  Views of Nation’s Economy Remain Positive, Sharply Divided by Partisanship (2/7/2020) provides the answer:

Currently, 81% of Republicans and Republican-leaning independents say the economy is excellent or good. These views have changed only modestly over the past two years. But between November 2016 (just before Trump’s victory in the presidential election) and March 2017 the share of Republicans with a positive view of the economy approximately doubled, from 18% to 37%. And by November 2018, they had doubled again, to 75%.

By contrast, Democrats’ assessments of economic conditions have changed only modestly since before Trump took office. Currently, 39% of Democrats and Democratic leaners say conditions are excellent or good. In November 2016, 46% had a positive impression of the economy.

The graph here is one of five in the report. The methodology section has more details and could be used in a statistics course.


How accurate are climate models?

The NASA Vital Signs of the Planet post Study Confirms Climate Models are Getting Future Warming Projection Right by Alan Buis (1/9/2020) reports

In a study accepted for publication in the journal Geophysical Research Letters, a research team led by Zeke Hausfather of the University of California, Berkeley, conducted a systematic evaluation of the performance of past climate models. The team compared 17 increasingly sophisticated model projections of global average temperature developed between 1970 and 2007, including some originally developed by NASA, with actual changes in global temperature observed through the end of 2017. The observational temperature data came from multiple sources, including NASA’s Goddard Institute for Space Studies Surface Temperature Analysis (GISTEMP) time series, an estimate of global surface temperature change.

The results: 10 of the model projections closely matched observations. Moreover, after accounting for differences between modeled and actual changes in atmospheric carbon dioxide and other factors that drive climate, the number increased to 14. The authors found no evidence that the climate models evaluated either systematically overestimated or underestimated warming over the period of their projections.

There are links to NASA data and graphs at the bottom of the post.

How hot was 2019?

From the NOAA Global Climate Report – Annual 2019:

The year 2019 was the second warmest year in the 140-year record, with a global land and ocean surface temperature departure from average of +0.95°C (+1.71°F). This value is only 0.04°C (0.07°F) less than the record high value of +0.99°C (+1.78°F) set in 2016 and 0.02°C (0.04°F) higher than the now third highest value set in 2015 (+0.93°C / +1.67°F). The five warmest years in the 1880–2019 record have all occurred since 2015, …

The report contains summaries by region and has abundance of quantitative information such as:

North America was the only continent that did not have an annual temperature that ranked among its three highest on record. Overall, North America’s temperature was 0.90°C (1.62°F) above the 1910–2000 average, marking the 14th warmest year in the 110-year continental record. The yearly temperature for North America has increased at an average rate of 0.13°C (0.23°F) per decade since 1910; however, the average rate of increase is more than twice as great (+0.29°C / +0.52°F per decade) since 1981.

The graphic here is from NASA, NOAA Analyses Reveal 2019 Second Warmest Year on Record (1/15/2020). Time series data can be obtained from Climate at a Glance Global Time Series.


How important is eating local in the carbon footprint of food?

The Our World in Data post You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local by Hannah Ritchie (1/24/2020) provides the graph copied here. From the article:

As I have shown before, food production is responsible for one-quarter of the world’s greenhouse gas emissions.

Overall, animal-based foods tend to have a higher footprint than plant-based. Lamb and cheese both emit more than 20 kilograms CO2-equivalents per kilogram. Poultry and pork have lower footprints but are still higher than most plant-based foods, at 6 and 7 kg CO2-equivalents, respectively.

Transport is a small contributor to emissions. For most food products, it accounts for less than 10%, and it’s much smaller for the largest GHG emitters. In beef from beef herds, it’s 0.5%.

The article itself doesn’t have data, but there are links to related Our World in Data posts about food with data.