Atmospheric acetylene over the last 22,000 years from the GISP2 ice core

Abstract:

Acetylene (C₂H₂) is a non-methane hydrocarbon released from burning of biomass, biofuels, and fossil fuels. Long term records of acetylene from ice cores can inform us about the variability in biomass burning through time. Past measurements of acetylene in ice core air indicate major changes in burning emissions over the past millennium, in agreement with other proxies such as methane isotopes and sedimentary charcoal (Nicewonger et al., 2020). Unlike methane, acetylene is a short-lived gas, and interpretation of ice core records must consider atmospheric transport and lifetime.

Here we present new measurements of acetylene over the last 22,000 years measured in air extracted from ice core samples from the Greenland Ice Sheet Project 2 (GISP2) ice core. These analyses were done using a wet extraction (melt) method (Nicewonger et al., 2018; 2020). Contemporaneous bipolar records of acetylene from GISP2 and the South Pole Ice Core (SPC14) will be analyzed to assess 1) changes in the global budgets of acetylene through time and 2) implications for biomass burning rates during the last glacial/interglacial transition and the Holocene.