December 19, 2019

Print Friendly, PDF & Email

Advancing Global Change Biology Through Experimental Manipulations: Where Have We Been and Where Might We Go?

An Evaluation of past experimental trends in Global Change Biology with commentary on future research.

The Science

The 25-year history of experiments reported in Global Change Biology was summarized to reveal past trends, and the authors offer subjective educated views on potential future directions.

The Impact

This describes recent trends in published experimental work and offers suggestions for potential future directions of experimental work associated with global change biology.


This commentary summarizes the publication history of Global Change Biology for works on experimental manipulations over the past 25 years and highlights a number of key publications. The retrospective summary is then followed by some thoughts on the future of experimental work as it relates to mechanistic understanding and methodological needs. Experiments for elevated CO2 atmospheres and anticipated warming scenarios which take us beyond historical analogs are suggested as future priorities. Disturbance is also highlighted as a key agent of global change. Because experiments are demanding of both personnel effort and limited fiscal resources, the allocation of experimental investments across Earth’s biomes should be done in ecosystems of key importance. Uncertainty analysis and broad community consultation should be used to identify research questions and target biomes that will yield substantial gains in predictive confidence and societal relevance. . A full range of methodological approaches covering small to large spatial scales will continue to be justified as a source of mechanistic understanding.  Nevertheless, experiments operating at larger spatial scales encompassing organismal, edaphic, and environmental diversity of target ecosystems are favored, as they allow for the assessment of long term biogeochemical feedbacks enabling a full range of questions to be addressed. Such studies must also include adequate investment in measurements of key interacting variables (e.g., water and nutrient availability and budgets) to enable mechanistic understanding of responses and to interpret context dependency.  Integration of ecosystem-scale manipulations with focused process-based manipulations, networks, and large-scale observations will aid more complete understanding of ecosystem responses, context dependence, and the extrapolation of results.  From the outset, these studies must be informed by and integrated with ecosystem models that provide quantitative predictions from their embedded mechanistic hypotheses. A true two-way interaction between experiments and models will simultaneously increase the rate and robustness of Global Change research.

Principal Investigator

Paul Hanson
Oak Ridge National Laboratory
[email protected]

Program Manager

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


This material is based on work supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT Battelle, LLC, for the U.S. Department of Energy under contract DEAC05-00OR22725.


Hanson, P. J., and A. P. Walker. "Invited Commentary: Advancing global change biology through experimental manipulations: Where have we been and where might we go?." Global Change Biology 26 (1), 287–99  (2019).