From Past to Present: Hydroclimate Variability in Global Drylands

Drylands cover roughly 45% of Earth’s land surface and support more than two billion people, yet they remain among the most data-sparse environments in the climate system. Arid and semi-arid regions across North and sub-Saharan Africa, the Middle East, Central and Inner Asia, inland South America, southern Africa, and arid Australia typically have short, spatially sparse, and unevenly calibrated instrumental records. This is a critical shortfall, since these environments act as early-warning systems for global hydroclimate change, amplifying even modest perturbations into pronounced ecological and societal impacts. Paradoxically, these same regions host some of the planet’s most responsive paleoclimate archives: speleothems, tufas, lake sediments, aeolian and fluvial deposits, pedogenic carbonates, tree rings, and historical documentary sources whose sensitivity offers a direct route to closing the observational gap.Despite the richness of these archives, the paleoclimate, historical-climatology, and modern-observational communities rarely engage with one another’s data or frameworks. As a result, the full envelope of dryland hydroclimate variability, the mechanisms driving its non-stationarity across climate states, and the relevance of past analogs to ongoing change remain poorly constrained, particularly in regions where short instrumental records make proxy and documentary evidence most valuable.This Research Topic seeks to bridge that divide by assembling cross-timescale hydroclimate evidence, from deep-time paleoclimate through the instrumental era, within the specific context of arid and semi-arid systems. Beyond building a coherent body of evidence, it aims to foster a lasting community of practice that bridges disciplinary silos, encourages shared data and methodological frameworks, and amplifies the contributions of researchers working in regions disproportionately exposed to climate risk yet underrepresented in the literature.ScopeContributions are invited to address questions including:o What governs the non-stationary behaviour of dryland hydroclimate across climate states?o To what extent can past variability constrain future drought and pluvial risk in data-sparse regions?o How can paleo, historical, and modern evidence be integrated to extend and contextualise the instrumental record in arid environments?We welcome Original Research, Reviews, Mini-Reviews, Methods, and Data Report articles. Suggested themes are grouped below; cross-cutting contributions are especially encouraged:Data and Archiveso High-resolution Quaternary proxy records of dryland hydroclimateo Historical-period droughts, pluvials, and megadroughts from documentary or early-instrumental sourceso Integration of proxy, historical, and modern records across timescalesMechanisms and Processeso Atmospheric-circulation controls on dryland rainfall (monsoons, westerlies, jets, teleconnections)o Non-stationarity of dryland responses to forcing and mean-state changeo Past and present hydroclimate extremes and land–atmosphere feedbacksMethodso Evaluation of reanalysis and remote-sensing products (e.g., ERA5-Land, CHIRPS, GRACE, SMAP) in data-sparse regionso Advances in dating, proxy calibration, and multi-archive synthesisImpacts and Adaptationo Detection and attribution of recent hydroclimate change in drylandso Implications for water resources, ecosystems, and adaptation in dryland societiesContributions led by or co-authored with researchers from underrepresented dryland regions are particularly encouraged. Topic editors: Kenneth Imo-Imo Eshiet, Khalil Azennoud Source: https://www.frontiersin.org/research-topics/84234/from-past-to-present-hydroclimate-variability-in-global-drylands