Future Meteorological Droughts in Ecuador: Decreasing Trends and Associated Spatio-Temporal Features Derived From CMIP5 Models

Lenin Campozano,Alex Avilés,Daniela Ballari,Martin Montenegro

doi:10.3389/feart.2020.00017

Abstract

Droughts are one of the most spatially extensive disasters that face societies. Therefore, it’s urgent to define mitigation strategies based on objective studies. However, research of droughts features in climate change (CC) have limitations due to the phenomenon complexity and the uncertainty of future precipitation from Global Climate Models (GCMs). The study of droughts in Ecuador is limited, despite the fact that CC will have more impact on developing countries. The study aims to assess the spatio-temporal characteristics of present and future droughts in Ecuador under 4.5 and 8.5 Representative Concentrations Pathways (RCP). Due to the intricate orography of Ecuador, e.g. coast, Andes and Amazon, the 10 km dynamically downscaled results from Couple Model Intercomparaison Project 5 (CMIP5). GCMs , GISS, CSIRO, and IPSL were used to calculate the Standardized Precipitation Index (SPI) droughts (present: 1981- 2005, future: 2041- 2070). The results show that overall there is a slightly decreasing trend of future droughts occurrence in the whole country, with larger reduction, for moderate, followed by severe and extreme. The intra-annual analysis shows that in the Andes and the coast, there is a reduction of moderate and severe future droughts for 4.5 and 8.5 RCPs and all DGCMs, throughout the year; extreme drought shows small decrease to statisticaly non-significant change. In the Amazon, moderate drought for IPSL and CSIRO show some increase/decrease in the probability of occurrence from May to October/rest of the year, for severe droughts the increase/decrease is expected from May to December/from January to april, and for extreme droughts increases are expected from January to April and higher increase in October and November. Thus, in the Amazon the rainy/drier period show a decreasing/increasing trend of droughts, which may be linked wetter in wet and drier in dry paradigm, although in the Andes and the coast may be different. Knowing that CC makes more challenging decision-making and adaptation strategies, this study contributes to the spatio-temporal representation of future droughts in Ecuador, highlighting areas and months where mayor changes are expected as well as the evaluation of GCMs ability to represent droughts in tropical mountains.

Highlights

Droughts are a transitory climatic anomaly, where the water availability is below average during a prolonged period of time limiting its supply for human needs and ecosystems
Evaluating Inter-model Uncertainties In Table 2 Root Mean Square Error (RMSE), Pearson correlation coefficient, and PBIAS are shown for the period 1981-2005 for precipitation and for Standardized Precipitation Index (SPI)-3, comparing observations and DGCMs evaluated over ground stations
The three DGCMs showed a similar performance of monthly precipitation estimates, the GISS model slightly outperformed the other two

Summary

Introduction

Droughts are a transitory climatic anomaly, where the water availability is below average during a prolonged period of time limiting its supply for human needs and ecosystems. Droughts in sensitive climate regions have world-wide effects, as it was the case for the 2005 and 2010 Amazon droughts (Espinoza et al, 2011), where the changes in net biomass and mortality of old rainforest affected the CO2 balance in the most important CO2 sink of the planet (Phillips et al, 2009) These facts made the complexity of this phenomenon explicit. Droughts are initiated by a meteorological drought, they generate a hydrological drought, which may produce an agricultural drought and, in cases of prolonged occurrence, may cause a socio-economic drought (Podestá et al, 2015). The final stage of a socio-economic drought may cause negative impacts, such as the loss of crops and livestock, a decrease in hydroelectric generation, migration, landscape degradation or social conflicts, among others (Wilhite et al, 2007)

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