# Climate Perspectives in the Intra-Americas Seas
## 5 Climate Change in the Regional Context
### The Anthropocene
#### 5.2.2 Future Climate Scenarios  
Long-term climate simulations for the 21 st century based on the Special Report on Emissions Scenarios (SRES) and Representative Concentration Pathways (RCPs) global scenarios are available as part of different global initiatives [236; 237]. These simulations have allowed the subsequent utilisation of global climate models to project future climate. In addition to the use of projections from the Coupled Model Inter-Comparison Project (CMIP)3 [238], CMIP5 [239], and CMIP6 [240], statistical [43; 241] and dynamic [242; 243; 244] downscaling techniques have been used to provide enhanced spatial scale representation of smaller areas. The implementation of these techniques is fundamental in representing the small islands of the Caribbean and better resolving complex regional topography to extract higher-quality information for the landmass [245]. The performance of downscaling is critically dependent on the driving global climate model [246]; as such, there needs to be careful interpretation of model outputs. Most CMIP3 models suggest a decrease in precipitation over the Caribbean under the SRES A2 scenario, while the CMIP3 ensemble median projections for the 2080s (relative to 1970-1989 mean) point to a drying of 30-40% in the western Caribbean and 20-30% in the eastern Caribbean [246]. Similar results have been reported in Reference [247] with drier conditions projected in SRES A2 and B2 scenarios for the Caribbean for 2071-2099 due to an increase in consecutive dry days. Independent assessments of changes to precipitation in Central America between 2021 and 2050 (with respect to the baseline 1961-1990), based on the RCP 4.5, suggest a rainfall decrease and the strengthening of the MSD in agreement with observed changes in recent decades. Rainfall projections show a contrasting decrease (increase) in northern (southern) Central America [248]. Under the warmest SRES A2, there is a consensus among simulations suggesting that Central America may experience significant drying during the summer months by the end of the 21 st century, relative to the first half of the 20 th century [249]. A higher frequency of extended dry seasons over the south of Mexico and Central America is projected based on the RCP8 for the end of the century. This drier scenario is associated with a larger warming of the Tropical North-Eastern Pacific (TNP) compared to the TNA [241]. The projected persistence of a strong CLLJ beyond July and November was linked to the perpetuation of a dry pattern in the Caribbean. The CMIP3 projections suggest a decrease in rainfall for most of Central America and Northern Venezuela, during all seasons, by the end of the 21 st century [250]. Such reductions in precipitation may result in the amplification of runoff changes in Central America, experiencing reductions from 10% to 30% in the A1B scenario by the end of the century [43]. Similar to Panama, the authors of Reference [251] identified that rainfall decreases may be followed by a runoff reduction, whereas there may be an absence of significant changes in the projected evaporation. Projected rainfall reduction for Central America and northern South America is accompanied by warming as well as an increase in evaporation and reduction in soil moisture [250]. The SRES A1B scenario suggests a 1.8 \({}^{\circ}\)C median annual increase in surface temperature in the Caribbean Sea by the end of the 21 st century compared to the 1980-1999 baseline. In southern Central America, the projected temperature may increase between 1.6 and 2.0 \({}^{\circ}\)C [248], and warming may be accompanied by a 21.42 cm of sea level rise by 2040 on the Caribbean and Central American coast under the RCP6.0 [252]. The CMIP5 indicates a temperature increase of 1.5 and 2 \({}^{\circ}\)C accompanied by a rainfall decrease of 5% and 10% for the RCP4.5 and RCP8.5 for Mexico, respectively. This is alongside north-south contrasts for rainfall projections featuring an increase-decrease pattern [253].