Black carbon deposits on birds

Using bird specimens from museums, researchers estimate black carbon aerosol concentrations during the early industrial period, according to a study. Combustion of organic matter, such as coal, generates atmospheric black carbon, which contributes to anthropogenic climate change. Estimates of early industrial emissions of black carbon are inexact, partly because black carbon sampling was uncommon prior to the mid-1950s. Using photometric reflectance data from museum specimens of birds collected from 1880 to 2015, Shane DuBay and Carl Fuldner measured the relative concentration of atmospheric black carbon deposited on more than 1,000 birds, capturing concentrations from the year each bird was collected. The birds were originally collected within the US Manufacturing Belt, which was historically reliant on coal-burning industries and includes Chicago, Detroit, and Pittsburgh. The authors found that regional black carbon concentrations peaked during the first decade of the 20th century and were linked with coal consumption through midcentury. After 1960, black carbon concentrations and coal consumption became decoupled, likely due to more efficient coal burning, increased availability of other fuels, and regulations on coal consumption. Furthermore, the authors found that black carbon concentrations were higher than previous estimates for 1880-1910, but were consistent with previous estimates after 1910. According to the authors, the past climate-forcing effects of black carbon may be underestimated.

Article #17-10239: "Bird specimens track 135 years of atmospheric black carbon and environmental policy," by Shane G. DuBay and Carl C. Fuldner.