Alaskan carbon-climate feedbacks will be weaker than inferred from short-term manipulations

Date Published
Using a mechanistic land model, Ecosys, to demonstrate that short-term (< 10 year) warming experiments produce emergent ecosystem carbon stock temperature sensitivities inconsistent with multi-decadal responses due to the tightly coupled, nonlinear nature of high-latitude ecosystems
Objective

To demonstrate that a well-tested mechanistic ecosystem model accurately represents observed carbon cycle and active layer depth responses to short-term summer warming in four diverse Alaskan sites; showing that short-term warming manipulations do not capture the non-linear, long-term dynamics of vegetation, and thereby soil organic matter, that occur in response to thermal, hydrological, and nutrient transformations belowground.

New Science

This study used a mechanistic land model, Ecosys, to demonstrate that short-term (< 10 year) warming experiments produce emergent ecosystem carbon stock temperature sensitivities inconsistent with multi-decadal responses due to the tightly coupled, nonlinear nature of high-latitude ecosystems.

Impact

While valuable for informing mechanisms stimulated under perturbation, short-term warming experiments cannot, by their nature, account for processes emerging on longer time scales that play a role in determining whether a site is a carbon sink or source. This study shows that short-term warming manipulations do not capture the non-linear, long-term dynamics of vegetation, and thereby soil organic matter, that occur in response to thermal, hydrological, and nutrient transformations belowground.

Image with caption
Image
Figure 1 - Bouskill

A graph showing short term warming over time for the sites of Utgia─ívik, Toolik, Delta Junction, and Eight Mile Lake. 

Citation(s)
Text

Bouskill NJ, Riley WJ, Zhu Q, Mekonnen Z, and Grant R. Alaskan carbon-climate feedbacks will be weaker than inferred from short-term manipulations. Nature Communications. https://doi.org/10.1038/s41467-020-19574-3

Funding

This research was supported by the Director, Office of Science, Office of Biological and Environmental Research of the U.S. Department of Energy under contract DE-AC02-05CH11231 to Lawrence Berkeley National Laboratory as part of the Next-Generation Ecosystem Experiments in the Arctic (NGEE Arctic) project.