Has left, larks rise-col-born at the beginning of the 20th century. Right, larks rise-collar who have lived through these past few years. — Copyright Carl Fuldner and Shane Dubai, The University of Chicago and The Field Museum
- 2 scientists have outlined a scheme of evolution of the air pollution in the United States from 1880 to 2015.
- They analyzed nearly 1,300 birds of five different species from an old industrial region in the northeast of the United States.
- The birds display the most beautiful colors today. But why ?
What can we say a dead bird on the evolution of the quality of the air ? A lot of things if one is interested in the dress of the volatile through the ages. It is precisely what makes Shane Dubai and Carl Guldner, phd students at the university of Chicago. By analyzing the color of the birds kept in the collections of museums, two american scientists have mapped out a schema of the evolution of the air pollution in the United States from 1880 to 2015, reports
The feathers of birds, with a lower loading of soot today
More specifically, the two american scientists have analysed nearly 1,300 birds of five different species, all derived from the ” Rust Bell “ (” the belt of the rust), a former industrial region in the north-eastern United States (Chicago, Cleveland, Pittsburgh, etc.). They are especially focused on the amount of
black carbon (that is to say, soot) present in the
larks rise-col, a small bird that will molt once per year and whose feathers can absorb a significant amount of soot. In short, the ideal candidate for this study.
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The full results of their work were published Monday in the Proceedings of the national academy of science. The study invites a degree of optimism, at least in terms of the amount of carbon black, considered as a responsible major global warming, in the air of the Rust Belt. We can say today that ” larks rise-neck are cute small birds in the bellies naturally white, and the chin yellow, written as Shane Dubai
in a press release. A hundred years earlier, when the smog was at the highest in the cities of the Rust Bell, these larks rise-col had a dress much more black. “
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Beyond this observation, Shane Dubai and Carl Guldner were able to trace a historical development that specifies the quality of the air in this former mining region. “The quantity of soot collected on the birds is closely linked to the use of coal over the years,” explains Shane Dubai. During the Great depression (1929-1939), this amount drops dramatically precisely because of the decline in coal consumption caused by the economic crisis. Then the rate of soot rebounds during the Second world war, the armament factories, leading to an increase in the production of coal, and then drops off rapidly in the aftermath of the war, when the foci of the Rust Belt start to heat the natural gas rather than coal. “
But if the birds of the Rust Bell displayed the most beautiful colours today, the two scientists fail to conclude that the quality of the air is much better today. “If the United States emit less black carbon today, we continue to release into our cities from other pollutants, note Shane Dubai. They are just less visible as soot. “