# Dynamics of Changes in Climate Zones and Building Energy Demand. A Case Study in Spain
## 3 Results and Discussion
### Determination of the Dynamics of Changes in Climate Severity Indices
#### 3.3.2. Proposed Update of Climate Zones for Peninsular Spain
Thus, by 2085, 23.89% and 19.82% of the localities will have a C3 and B4 climate classification, while the coldest climate zones will disappear (Table 4). In winter CZs (Table 3), for the periods 2055 and 2085, practically 90% of the localities will change their climate zoning compared to that retained in the CTE. Specifically, for the period 2055, 44.8% of the localities will change their zoning to a warmer one and 40.5% of the localities to two warmer zones. Similarly, by 2085, 41%, 43.4%, and 4.7% of localities will change their winter rating to 1, 2, and 3 warmer zones, respectively. Thus, the geographical distribution of winter climate zones for 2085 resembles the resulting distribution for 2055, where only 8% of cities will observe zone changes between these two years. The increase of the A rating concerning the CTE (Figure 6c,d and Table 4), from 0.74% in the CTE to 12.89% and 15.97% in 2055 and 2085, respectively, stands out. In contrast, the E rating decreases drastically from 28.76% in the CTE to only 2.6% in 2085. These results again show that the trend towards warmer and warmer areas will continue throughout the century. In the summer CZ case (Table 3), for the periods 2055 and 2085, 88.6% and 87.6% of the locations will change their climate zonation compared to the CTE. By 2055, 47.7% of localities will change their zoning to a warmer one, and 39.4% of localities will change their zoning to two warmer zones. Similarly, by 2085, 48.3% and 38.1% of localities will change their summer rating to 1 and 2 warmer zones, respectively. As in the winter season, the differences between 2055 and 2085 are not significant. Although, throughout this scenario, there is a significant increase in rating 4 in the localities concerning the CTE (Figure 6c,d and Table 4), from 8.55% in the CTE to 49.51% and 49.60% in 2055 and 2085, respectively. In contrast, rating 1 decreases drastically from 40.05% in the CTE to only 2.11% in 2085. These results demonstrate the need to develop new summer zones within rating 4, with the consequent improvement in terms of building recommendations. Proposed Climate Zones for Peninsular Spain for the RCP 8.5 Scenario Projections  
Under the RCP 8.5 scenario (Table 3) for 2055 and 2085, a drastic increase in the change of climate zone classification (winter + summer) concerning the CTE is foreseen, showing that 98% of the cities will be affected. Furthermore, Figure 6e,f shows that the geographical distribution of climate zones for 2085 will undergo a significant dynamism, with zones A4 and B4, with 39.74% and 41.63%, dominating the peninsula. These zones are characterized by mild winters and sweltering summers, leading the peninsula to have climates more typical of tropical regions by the end of the century. In the winter CZs (Table 3), for the periods 2055 and 2085, 92.4% and 100% of the locations will change their climate zoning compared to the CTE. Specifically for the period 2055, 24.4, 33.1, and 26.5% of the localities will change their qualification by one, two, and three warmer zones, respectively. Similarly, by 2085, 10.1, 36.7, and 35.4% of localities will change their winter rating to one, two, and three warmer zones, respectively. Throughout this scenario, there is a significant increase in the presence of the A and B rating in the localities concerning the CTE (Table 4), from 0.74 and 5.47% in the CTE to 42.95 and 51.54% in 2085, respectively, on the contrary, the C and D ratings decrease drastically, while the E climate zone disappears entirely by 2085. These results are due to the already indicated trend towards warmer and warmer zones. In the summer CZ case (Table 3), for the periods 2055 and 2085, 82.7% and 91% of the localities will change their climate zoning compared to the CTE. By 2055, 33% of the localities will change their zoning to a warmer one, 25.5% of the localities to two warmer zones, and 18.9% to three warmer zones. Similarly, by 2085, 31%, 26.3%, and 32.2% of localities will change their summer rating to 1, 2, and 3 warmer zones, respectively.