PNNL

The Science                       

Climate-driven disturbances such as heat, drought, wildfire, and insect outbreaks are increasing around the globe and are predicted to rapidly accelerate under future environmental conditions. These disturbances affect ecosystems' abilities to provide food, water resources, energy, and other essential resources and services to society. In a study led by a scientist at the U.S. Department of Energy's Pacific Northwest National Laboratory, researchers developed a new theory regarding the effects of chronically increasing disturbances on critical ecosystem functions. They applied this theory to potential Earth system model advances that could help address chronic imbalances in ecosystem services.

The Impact

Predicting chronic imbalances in ecosystem services via Earth system models can improve planning to ensure continued provision of services to society. While researchers focused on how drought and rising temperature affect hydrologic services such as streamflow, water yields, and aquifer recharge, the new framework could include additional events that are expected to increase in likelihood, such as floods and storms. It also could extend to different kinds of ecosystems in which disturbances are expected to become more frequent.

Summary

Scientists reviewed evidence of disturbed ecosystem functions, specifically carbon storage and hydrologic services (e.g., water availability for power generation, drinking, and agriculture). From this data, they developed a theory underlying prolonged climate-driven disturbances and their increasing frequency, which could result in chronic imbalances of ecosystem services. Their theory suggested that warming and drought would lead to chronic mortality. With more frequent disturbances, biomass would disappear more rapidly and would not be regained. This imbalance would correspond with an increasing human population—and demand—for ecosystem services.

Researchers proposed that Earth system models address the possible impacts of chronic imbalances when simulating ecosystem services. For example, next-generation models of future ecosystems could account for new conditions and processes without relying on data based only on past behavior.

Funding

The U.S. Department of Energy Office of Science, Biological and Environmental Research supported this research. NGM, KB, SM, KS, CX, and RSM acknowledge the support of Los Alamos National Laboratory's Laboratory Directed Research and Development (LDRD) program. NGM acknowledges the support of Pacific Northwest National Laboratory's LDRD program. RMM acknowledges the support of the National Science Foundation grant WSC-1204787.

Publication

N.G. McDowell, S.T. Michaletz, K.E. Bennett, K.C. Solander, C. Xu, R.M. Maxwell, C.D. Allen, R.S. Middleton, "Predicting Chronic Climate-Driven Disturbances and Their Mitigation." Trends in Ecology and Evolution, in press (2017). [DOI: 10.1016/j.tree.2017.10.002]