“Uncovering the Impact of Rising Temperatures on Northern Forest Soils: A Groundbreaking Experiment Reveals Troubling Findings”

The soils of northern forests play a crucial role in storing carbon dioxide and preventing it from re-entering the atmosphere, but a new study led by Peter Reich of the University of Michigan has revealed concerning findings. The experiment, published in Nature Geoscience and led by Reich and his team, shows that on a warming planet, more carbon is escaping the soil than is being added by plants.

Reich, who is also the director of the Institute for Global Change Biology at U-M, expressed his concerns about the implications of this discovery. “Losing more carbon is always going to be a bad thing for climate,” he said. The lead author of the study, Guopeng Liang, emphasized the importance of understanding how rising temperatures impact the flow of carbon in and out of soils to better predict climate changes.

Forests store approximately 40% of the Earth’s soil carbon, making them critical in the fight against climate change. Previous research projects have studied the effects of climate change on carbon flux from forest soils, but few have lasted longer than three years and most have only focused on either soil or air temperature, not both.

Reich’s experiment, believed to be the first of its kind, controlled both soil and above-ground temperatures in open air settings for over a dozen years. The study, conducted in northern Minnesota with the support of the National Science Foundation, the U.S. Department of Energy, and the University of Minnesota, involved 72 plots with two different warming scenarios compared to ambient conditions.

The results showed that soil respiration, the process that releases carbon dioxide, increased by 7% in plots with a modest temperature increase and by 17% in plots with a more extreme temperature rise. The researchers found that the carbon dioxide released by microbes feeding on carbon-containing substances in the soil did not increase as much as expected due to the decrease in soil moisture at higher temperatures.

Reich highlighted the importance of these findings, stating that forests are likely to lose more carbon than desired, but the impact may be mitigated by factors such as soil moisture levels. The study underscores the complex relationship between temperature, soil moisture, and carbon flux in forest ecosystems, providing valuable insights for climate change mitigation efforts.