BURNice: Global biomass burning reconstruction using ethane in polar ice cores

The BURNice project aims to quantify global fire emissions during important climate events from the Holocene to the last interglacial termination using ethane in polar ice cores. The project aims to combine analytical measurements and model simulations to explore the fate of ethane (C₂H₆) in the atmosphere in the past. Ethane is a short-lived non-methane hydrocarbon with a simple atmospheric budget. Ethane is primarily emitted into the atmosphere by fire and is removed via reaction with OH and Cl radicals, resulting in a lifetime of ~2 months.

Measurements of ethane in ice cores are conducted using continuous sublimation extraction (CSE) method in tandem with GC-IRMS for parallel quantification of ethane, methane (CH₄), methane isotopes (δ¹³CH₄), and other trace gases. We perform simulations using the Community Earth System Model (CESM) with an improved representation of halogen chemistry to investigate the spatio-temporal dynamics of ethane in the paleo-atmosphere. Preliminary results focus on the effect of the Cl-sink on ethane in modern-day, which is poorly constrained.

This study presents 1) advancements in measurements of ethane in NH and SH ice cores using CSE-GC-IRMS, and 2) results of sink-varied modern-day simulations of ethane in the atmosphere using CESM.