# Regional Climate Change in Southeast Mexico-Yucatan Peninsula, Central America and the Caribbean
## 4 Discussion
### Projections Trends under Climate Change Scenarios  
The 25-year trends indicate that the RCP 6.0 trends will remain in both future periods over the CRU trends for the temperature anomalies. In the case of the Pre, anomalies are positive for Mexico and are inverse for CA and the Caribbean. This last result is in agreement with the studies by [13; 73]. While high latitudes show increasing precipitation, lower latitudes show decreasing precipitation. CA is shown to be dry in the future, with the exception of Guatem. In [20], the authors report the same results. In [26], the authors state that precipitation would decrease under the Special Report of the Emission Scenarios (SRES) during 2071-2100 [83].  
Pre trends show some discrepancies in terms of the behavior of temperatures (i.e., RCPs trends are negative for 2015-2039). In the period of 2075-2099, the trends show same negative difference. This result confirms that the GCMs performance has low confidence for the Pre variable [9; 22; 58; 84].  
The present results are only preliminary for each point, and a complete spatial study should follow. This study suggests a better RCP scenario of the three ones for the study points of the entire region, from the comparison of the trends for each scenario RCP over the CRU trends. There is a good consensus that, during 2015-2039, the trends will maintain the speed of the historical trends. For the far-future (2075-2099), the radiative forcing evolution [2] will be reflected in the trends. Two RCP scenarios are marked with this method, and RCP 6.0 is more ad-hoc for SM-YP and CA. For the CA, RCP 8.5 could likely produce the same result; this is in agreement with [85]. For the Caribbean, the RCP 4.5. The [3] study method to determine the most probable scenario is consistent with this for SM-YP. These results, presented in Figure 5, suggest that the radiative force is higher for the SM-YP and CA region than for the Caribbean, as the Caribbean is influenced by other climate factors (see Section 3.2). In [29] shows that, for the Caribbean, the warming could be greater for the last century, close to 2.5 \({}^{\circ}\)C. This is the case according to the current result, and [2] reports that RCP 4.5 has an average probability of going from 2 \({}^{\circ}\)C (11 to 2.6 \({}^{\circ}\)C). This study proposes that the historical trend could discriminate the RCP between the three scenarios. Furthermore, the historical results show that the same warming exists throughout the study region.  
In [3], the authors show the probability for each of these three scenarios (RCP 4.5, RCP 6.0, and RCP 8.5). For the south-southeast of Mexico, RCP 4.5 and RCP 6.0 are the most accepted scenarios. The three scenarios show different behavior for the SM-YP region, and the RCP 6.0 scenario is the most ad-hoc. It is known that the driest scenario is RCP 8.5, and the least dry is RCP 4.5 for the SM-YP, while RCP 6.0 is dry in the first projected timeframe (2015-2039), but it could change in the second middle of the century from dry to wet. As such, the RCP 6.0 scenario could be the trend scenario for the entire study region. This exercise is the first step in this direction to determine what ad-hoc scenario best fits the region.