October 20, 2020

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Alaskan Carbon-Climate Feedbacks Will Be Weaker Than Inferred from Short-Term Experiments

The Science

Climate warming is occurring fastest at high latitudes; however, a question remains as to how representative short-term warming manipulations are of tundra responses to a changing climate. Here researchers from NGEE-Arctic use a well-tested mechanistic land model to examine differences in ecosystem carbon cycle responses between observed and modeled short-term (<10 year) warming experiments and modeled long-term (100 year) changes under 21st century expected temperature, precipitation, and COconcentrations. Their simulations show that short-term experiments disturb the tundra carbon cycle in ways that are inconsistent, and stronger, than ecosystem responses to multi-decadal climate change (Bouskill et al., 2020).

The Impact

The experimental simulations show that short-term warming resulted in a much higher rate of soil carbon loss relative to multi-decadal responses. This can partly be attributed to long-term perturbation occurring at a lower rate of change. However, the short-term warming experiments favor heterotrophic activity, and hence soil carbon loss, and generally are not designed to capture longer-term, non-linear dynamics of vegetation, that occur in response to thermal, hydrological, and nutrient transformations belowground.


Climate warming is occurring fastest at high latitudes. Based on short-term field experiments, this warming is projected to stimulate soil organic matter decomposition, and promote a positive feedback to climate change. Scientists from NGEE-Arctic show here that the tightly coupled, nonlinear nature of high-latitude ecosystems implies that short-term (< 10 year) warming experiments produce emergent ecosystem carbon stock temperature sensitivities inconsistent with emergent multi-decadal responses. They first 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. Next they found  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. These results demonstrate significant spatial heterogeneity in multi-decadal Arctic carbon cycle trajectories and argue for more mechanistic models to improve predictive capabilities.

Principal Investigator

Nicholas Bouskill
Lawrence Berkeley National Laboratory

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science


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.


Bouskill, N. J., W. J. Riley, Q. Zhu, Z. A. Mekonnen, and R. F. Grant. "Alaskan carbon-climate feedbacks will be weaker than inferred from short-term experiments". Nature Communications 11 5798  (2020). https://doi.org/10.1038/s41467-020-19574-3.