20th-Century Industrial Black Carbon Emissions Altered Arctic Climate Forcing

TLDR

Black carbon from biomass and fossil fuel combustion changes atmospheric chemistry and snow albedo, but its emission and deposition histories remain poorly understood. Ice‑core records show BC concentrations in Greenland precipitation rose sevenfold from ~1850, peaking 1906–1910 with ~3 W m⁻² surface forcing, then fell after 1951 but have been increasing again, reflecting shifts from boreal fires to industrial emissions.

Abstract

Black carbon (BC) from biomass and fossil fuel combustion alters chemical and physical properties of the atmosphere and snow albedo, yet little is known about its emission or deposition histories. Measurements of BC, vanillic acid, and non-sea-salt sulfur in ice cores indicate that sources and concentrations of BC in Greenland precipitation varied greatly since 1788 as a result of boreal forest fires and industrial activities. Beginning about 1850, industrial emissions resulted in a sevenfold increase in ice-core BC concentrations, with most change occurring in winter. BC concentrations after about 1951 were lower but increasing. At its maximum from 1906 to 1910, estimated surface climate forcing in early summer from BC in Arctic snow was about 3 watts per square meter, which is eight times the typical preindustrial forcing value.