How Much Will Soil Warm?

Abstract

For years, carbon cycle scientists have sought to understand how a warming climate will impact the decay of soil carbon. However, there have been relatively few investigations of how soils will warm in comparison to the atmosphere. Three recent papers in American Geophysical Union journals have looked at expected soil warming by synthesizing predictions in the Climate Model Intercomparison Project 5 (CMIP5). Collectively, these papers show that soil warming will keep pace with air warming except where snow and ice occur, and that the magnitude of soil warming in northern latitudes is uncertain due to model variability in snow and ice extent. They also show that a considerable portion of anthropogenic warming is being stored in deep soils, and that in comparison to observations, soil heat storage is underrepresented by land models. These studies highlight how important continued investigations of soil climatology are to understanding carbon cycling and Earth energy balance.

Temperature optimum for marsh resilience and carbon accumulation revealed in a whole‐ecosystem warming experiment

“…Some studies have attempted to replicate these temperatures experimentally in salt marshes using aboveground heating lamps or passive heating systems (Charles & Dukes, 2009; Coldren et al, 2016; Gedan & Bertness, 2009; Zhong et al, 2019). While these designs have successfully simulated increased temperatures at the marsh surface, these methods fail to increase temperature at deep soil depths (~1 meter) that are expected to warm under future climate conditions (Phillips, 2020). Given the large, deep stores of organic material that have accumulated in marshes over time, these passive, surficial warming designs neglect to warm a significant portion of soil organic material that will experience warming in the future.…”

Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

“…While the impacts of realistically deep land components have been investigated with standalone LSMs and analytical models, they have not yet been considered in the frame of ESM coupled simulations (Phillips, 2020). Here, we hypothesize that ESMs with deeper land model components not only show larger land heat storage but are consequently adjusting the distribution of excess heat among the climate system components toward fractions closer to observational estimates.…”