Hydroclimatic Change in a Warming World (Invited)

The Earth’s water cycle is changing, with consequential impacts felt on scales ranging from global to local. Large-scale changes with atmospheric warming include increased precipitable water, longer atmospheric residence times, decreased continental moisture recycling, and greater atmospheric demand for evapotranspiration. These large-scale changes alter regional precipitation patterns, which in turn affect runoff, soil moisture, and land-atmosphere feedbacks. Soil moisture limitation is a critical determinant of local hydroclimate, thus changes in the distribution of soil moisture availability is key piece of the puzzle needed to understand hydroclimatic change in a warming world. The collective impact of these changes manifest in some regions through exacerbation of daily maximum temperatures, in others as a temporal elongation of the dry season, and in others through greater disparities in water availability between wet and dry seasons. These changes also heighten vulnerabilities to societal and ecological challenges such as heatwaves, droughts, and floods. This discussion will focus on local mechanistic processes at the heart of the hydrologic cycle and weave together results from multiple studies to provide a broad vision of how and why Earth’s water cycle is changing in different regions of the globe.