How Exceptional Was the 2015–2019 Central American Drought?

Abstract

The Central American Dry Corridor experienced five consecutive years of drought from 2015 to 2019. Here, we find that the severity of this drought was driven primarily by rainfall deficits in July–August. To determine if the magnitude of this event was outside the range of natural variability, we apply a statistical resampling method to observations that emulates internal climate variability. Our analyses show that droughts similar to the 2015–2019 event are possible, although extremely rare, even without anthropogenic influences. Persistent droughts in our ensemble are consistently linked to stronger easterly winds associated with the Caribbean Low-Level Jet. We also examine the effects of temperature on soil moisture during this drought using the Palmer Drought Severity Index and show that anthropogenic warming increases the likelihood of severe deficits. Multi-year droughts are likely to worsen by the end of the 21st century due to the compound effects of anthropogenic climate change.