Climate Change Detection in the Intra-Americas Region and Local Implications to Sensitive Eco-systems

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Monday, 5 January 2015
Equisha Glenn, City College, New York, NY; and D. Comarazamy and J. Gonzalez

Global climate change manifests in the Intra-Americas Region (IAR) as increased sea surface temperature (SST), precipitation anomalies, and changes in atmospheric moisture content, among other effects with possible consequences to local ecosystems. The IAR, defined as the geographical region that includes the Caribbean, Mexico, Central America and parts of North and South America, is a distinctive region of dynamic climatological phenomena that is particularly sensitive to global climate changes. A 30-year analysis of high resolution SST data revealed a warming trend for the IAR during the 1982 – 2012 period. Using an optimum interpolated sea surface temperature (OISST) product with spatial resolution of 0.25 degrees, the 30-year climatological analysis was generated to observe annual, monthly, and seasonal trends. Results show that on a regional scale SSTs are increasing annually and during the two distinct Caribbean rainy seasons – the Early Rainfall Season (ERS), at an estimated 0.0161°C/year, and the Late Rainfall Season (LRS), at an estimated 0.0209°C/year, both with high statistical significance. Sub-regional analysis revealed that warming has occurred particularly in the Gulf of Mexico and North of South America during the ERS and LRS, also with high statistical significance. Additionally, LRS decadal averages for 2003-2012 reflect an increase in the magnitude and intensity of the Atlantic Warm Pool (AWP) relative to the 1983-1992 period.

These regional changes in SST are believed to have a great impact on local sensitive ecosystems located within the IAR; one such case is the Enriquillo lake basin in the Dominican Republic-Haiti border in southwestern of Hispaniola Island. The major bodies of water in the basin, Lake Enriquillo and Lake Azuéi, show a shrinking and expanding pattern since the early 1980s. Surface area of Lake Enriquillo was observed to reach minimum values in 2004, shifting to rapid expansion to its current levels, which is double its minimum size (>350 km2 as of late 2013). Lake Azuéi is observed to grow at similar rates. This lake expansion could be attributed to the increasing SSTs and associated increase in moisture transport. Local conditions reflect increasing air temperatures (~0.37 ˚C decade-1), dew point (~0.66 ˚C decade-1), and precipitation (~30%). The hypothesis of lake expansion in the Enriquillo basin as a regional response to climate change is further investigated with the use of an integrated regional atmospheric modeling system. Model results show increased total accumulated surface precipitation, atmospheric liquid water content, and an enhanced positive feedback system that produces orographic cloud cover in the surrounding tropical montane cloud forests during the lakes' growth period (2003-2013) as a consequence of the changing atmospheric and oceanic conditions. The socio-economic implications of these sudden environmental changes are evident, as large portions of flooded land have misplaced entire communities, destroyed roads and farms, and affected trade near the border crossing.