# Quantifying Arctic-boreal methane emissions using atmospheric observations and a global inverse model

## TL;DR

This study uses atmospheric data and a global model to estimate methane emissions in the Arctic-Boreal region, finding that warming and wetness changes influence emissions.

## Contribution

The study introduces a global inverse model to quantify Arctic-Boreal methane emissions with reduced uncertainty and identifies regional trends linked to climate factors.

## Key findings

- Arctic-Boreal emissions averaged 45.4 ± 0.7 TgCH4 y−1 from 2010 to 2021, with no significant overall trend.
- Western Siberia Lowlands showed a positive emission trend linked to warmer temperatures and wetter conditions.
- Winter hydroclimate changes, like snowmelt, significantly affect emissions in the Western Siberian Lowlands.

## Abstract

The Arctic-Boreal region is vulnerable to rapid climate change. Thawing of the permafrost and extended warm periods are expected to turn the region into a hotspot of enhanced CH4 emissions. We estimated CH4 fluxes by assimilating atmospheric CH4 mixing ratio data from a regional network into a global atmospheric inverse model, resulting in a mean uncertainty reduction of ~68% across the domain and improved agreement with observations. From 2010 to 2021, the Arctic-Boreal region emitted 45.4 ± 0.7 TgCH4 y−1 ( ~ 7% of global emissions), with no significant overall trend. However, on the regional scale a positive trend emerged in the Western Siberia Lowlands. Arctic-Boreal wetland emissions increased during warmer years, suggesting possible future increases as warming continues. Emissions varied regionally, with western Russia showing higher fluxes. Changes in winter hydroclimate significantly influenced emissions in the Western Siberian Lowlands, likely by enhancing the availability of soil moisture through snowmelt in spring. Our findings emphasize the importance of accounting for both temperature effects and changes in wetness, when assessing Arctic CH4 future emissions.