Joeran Maerz

Addendum to: Nature Climate Change https://doi.org/10.1038/s41558-024-02074-3, published online 12 August 2024. The yearly increase in atmospheric CO2 due to Arctic coastal erosion (up to 7–13 TgC per year in SSP5-8.5) is between three and four orders of magnitude smaller than anthropogenic CO2 emissions, currently estimated at about 10 PgC per year1 (1 Pg = 1,000 Tg). The rate of increase in the atmospheric CO2 due to erosion increases with warming, which configures a positive climate feedback.

Abstract Arctic coastal permafrost erosion is projected to increase by a factor of 2–3 by 2100. However, organic matter fluxes from the coastal permafrost into the ocean have not been considered in Earth system models so far. Here we represent coastal permafrost erosion in an Earth system model and perform simulations with varying permafrost organic matter properties, such as sinking fraction and nutrient content.