On the observed and projected hydroclimate change in the Caribbean between 1950 and 2100

Abstract:

The Caribbean Islands might suffer from increased aridity as a result of anthropogenic-driven climate change in the coming decades. Concurrently, many paleoclimate records suggest the occurrence of decadal and multidecadal droughts in the Circum-Caribbean region during the last millennium. Understanding drought variability, its trends, and dynamical causes are, therefore, critical for improving the resiliency and adaptation capacity of this region, as well as to improving the predictability of hydroclimate extremes across spatial and temporal scales. Here, we present a review of the literature on the Caribbean’s hydroclimate variability and its projected change. We highlight the limitations for assessing drought risk in the Caribbean Islands, including constrains in the horizontal resolutions of current gridded climate products, both observational and modeled products. Between 1950 and 2016, there is a significant drying trend in the Caribbean as estimated from the “self-calibrating” Palmer drought severity index (scPDSI). Linear trends in scPDSI average a change of −0.09 decade^-1 (p < 0.05). However, this trend is not homogeneous, and significant trends toward wetter conditions are observed in portions of the Caribbean, which emphasize the importance of high-resolution climate data (e.g., 4 km) for assessing drought risk in the Caribbean Islands. We also find a strong influence of both tropical Pacific and North Atlantic oceans in modulating drought variability in the Caribbean, a condition that prevails since at least the last millennium. Hydroclimate projections based on the “shared socio-economic pathway” (SSP) 5 scenario of the Coupled Model Intercomparison Project phase 6 (CMIP6) further suggest a significant drying (p < 0.05) for the Caribbean through the 21st century, with changes in precipitation, evapotranspiration, and scPDSI of –0.02 mm day^-1 decade^-1, 0.02 mm day^-1 decade^-1, and –0.17 units decade^-1, respectively. These results strongly suggest that the Caribbean is one of the regions projected to suffer from more severe and prolonged droughts as a consequence of anthropogenic climate change. However, the current climate models’ horizontal resolutions preclude a more accurate projection at local and regional scales.