Drought, despite being an episodic phenomenon, is capable of triggering persistent changes to ecosystems, with important consequences for both biodiversity and human communities. These transformational ecological droughts (TEDs) are increasing globally as a function of changing drought conditions, compounding stressors (including competing water use with humans), land management legacies, and novel climate contexts. Making decisions about how to adapt to these transformations is impaired by a limited recognition of the widespread potential for TEDs, a lack of understanding about the mechanisms by which transformation may occur, and uncertainty about the potential ecological trajectories such transformations will take. In this presentation, I will share the results of an interdisciplinary science synthesis that focused on how the risk of transformational drought is changing in the 21st century. I will provide a broad overview of the phenomenon of TED, including the diverse pathways by which it leads to transformation, highlighting mechanisms and case studies relevant to the North Central region.

Recent observed increases in wildfire activity across the contiguous United States (U.S.) and the increasingly apparent effects of climate change on fire regimes have created novel challenges for fire and ecosystem managers requiring more robust information on changes in future fire risk, especially for the largest fire events, over the next several decades. Today, the majority of wildfire ignitions are caused by human activities—so capturing anthropogenic aspects of changing fire activity beyond those associated with climate change is critically important. In this work, we use a Bayesian statistical model that includes projections of where people will be located on the landscape, as well as projections of future atmospheric conditions from downscaled climate model simulations using a moderate warming trajectory (RCP 4.5), to make predictions regarding the number, size of the largest fire, and overall area burned by wildfires in each Environmental Protection Agency (EPA) level-3 ecoregion across the U.S. over the next four decades. By 2020-2060, we project an average increase in the number of fires (+56%) and burned area (+59%) across the U.S. compared to the historical period (1984-2019). For the largest fire events, we find nearly ubiquitous increases across all ecoregions (contiguous U.S. average +63%). Overall, our results suggest that climate change in the coming decades will drive more frequent occurrences of fires in regions where wildfire was rare (i.e., much of the eastern U.S.), and unprecedented increases in the size of the largest fires in regions where fires were common (i.e., in the western United States).