The dynamics of drought are fundamental to understanding how the risks of these extreme events may change in response to greenhouse warming. But the causes of drought are complex: interactions between the atmosphere, ocean, land surface, and human-induced changes to each can be responsible for initiating persistent drought events. Unforced internal climate variability can also have significant effects on drought, meaning that detecting a climate change signal requires an estimate of the background level of natural variations. To understand the dynamical processes generating drought in our study regions, we take advantage of insights from both data (the modern instrumental and paleoclimate archives) and Earth system models. We are interested in understanding:
- The role of coupled modes of climate variability (El Nino/Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation) in generating drought events
- The response of climate modes to external forcing (greenhouse gases, volcanic eruptions)
- Sources of disagreement between models and data: what are the uncertainties in projections of future drought from Earth System Models?