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Expected impacts of climate change in the Basque Country
Climate change, according to the first results of available models, results, in the Basque Country, in a raining estimated reduction of between 15 and 20% per year, with increases in winter and decreases in summer. Extreme maximum temperatures for the end of the century can raise between 1.5°C and 3.5°C; and extreme minimum ones between 1°C and 3°C. This thermal increase causes a higher evapotranspiration and a higher risk for forest fires.
Increase in sea level and waves force is significant, since it shall cause a backward movement of coastline in beach areas of between 11 and 13 m about the middle of XXI century and the risk of flood in estuaries.
Priority performances have been identified according to expected impacts in natural and economic systems, human health and performance capacity. Although impacts are not well known and started researches must be expanded, also for the development of scenes adapted to the Basque Country dimensions, economic cost-effectiveness to undertake early performances becomes evident.
Physical consequences
Two of the main climate variables which shall be affected because of climate change are temperature and rainfall. Regarding the last one, both global and specific models suggest a decrease of rainfall in the southern region. These models also foresee a yearly reduction in rainfall, particularly during summer months, which in the case of the Basque Country is estimated between 15 and 20%.
The change in distribution of rainfall through the year does not show a clear behaviour pattern, which indicates a quite low reliability of projections, which suggest a increase of it for winter months (December to February) estimated between a 5 and 20% and a decrease for summer months (June to August) estimated between a 30 and 50%. The main pluviometric change might be more conditioned by the seasonal distribution of rains (with a higher space and temporal heterogeneity) than by the very percent diminution in absolute values[1].
Regarding temperatures, projections for XXI century[2] show an increase of average temperature up to 5–7°C in summer and 3–4°C in winter, which in coast are reduced in 2°C. Predictably, the number of days with extreme maximum temperatures shall increase, and the ones with extreme minimum temperatures shall decrease. In the specific case of the Basque Country,[3] for the last third of XXI century a 1.5°C increase of extreme maximum temperatures[4] in coastline and 3.5°C in the rest of territory is expected. With regard to extreme minimum temperatures (as monthly averages) a increase between 1 and 1.5°C is estimated in the coastline, between 2 and 2.5°C in the rest of the Atlantic basin and middle area and between 2.5 and 3°C in the southern region of the Basque Country. Seasonally, the extreme maximum values present differences between the different climate regions of the Basque Country. These values are shown in the following chart.
This thermal increase results in a higher evapotranspiration (13 mm/decade for every 0.10°C/decade of temperature increase, which might mean between 130 and 910 mm for the end of XXI century depending on whether we take into account the coastline or the interior) and a higher forest fires risk. Other variables likely to be modified in the Basque Country, like cloudiness, relative humidity and wind speed are collected in the following chart.
Seasonal and territorial distribution of other climate variables
| Weather variable | Geographic area Basque Country | |||
|---|---|---|---|---|
| ATLANTIC (% variation) | AVERAGE/SOUTH (% variation) | |||
| Winter | Summer | Winter | Summer | |
| Cloudiness | Up to +10% | -15 to -25% | No significant change | -20 to -35% |
| Relative humidity | No significant change | Up to -10% | 0 to -5% | -5 to -15% |
| Wind speed | 0 to -5% (coastline) | 0 to -10% (no shore line) | 0 to 15% | 5 to 20% |
| 0 to +5% (coastline) | Up to +10% | |||
One of the most significant problems derived from climate change to face in the Basque Country is the increase of the sea level and the energy of the swell (higher waves and longer storms) together with a change of its direction (2° to the west). The most exhaustive report in state referring to affection to the coast[5] estimates an increase of sea level of 0.4 cm/year, which would mean an increase of about 40 cm at the end of XXI century. This increase in sea level shall cause the 11–13 m backward movement of coastline in beach areas about the middle of XXI century, changes in coastal morphology and loss of stability and rebasing of works and coastal infrastructures (worthwhile with an increase of their area between 6 and 20%). In the estuaries, as well as a potential space or temporary regime more irregular, the main danger is the flood risk of coast human settlements (urban, agricultural and industrial) and particularly in estuaries of big cities like Bilbao and Donostia (see PIPI [Flood Risk Plan]).
Impacts on natural, social and economic systems
The Basque Country has a protecting measure in the 22.7% of its territory. However, as a result of climate change, changes in animal and vegetable communities are expected, including an advance or delay in migration or reproduction periods, hormonal changes, changes in the distribution of continental and sea species (in the case of some sea species changes in latitude and depth have been stated), modification of productivity, modifications in invading and parasitic species, increase of vulnerability or population changes (increase or decrease of number of individuals depending on the considered specie). Vulnerability is the maximum for endemic and especially interesting species (amphibian and reptiles). Moreover, the possible loss of organic carbon of ground would reduce its fertility for tree species and brushes.
Water resources have a limited storing capacity (about 60 Hm³) and are very conditioned by rainfall, so a more heterogeneous distribution of rainfall shall cause a higher variability, resulting in temporary situations of water shortage, which, however, might be solved by means of a suitable management system.
In primary sector, the 390,000 Ha exploitation of tree forest surface (54% of the Basque Country total surface) shall have its productive period changed (deciduous leaf species shall be benefited against perennial ones), an aspect which can cause some species not to be profitable and be replaced with imports. Also, a greater difficulty to overcome the summer drought stages has been predicted. This change in productivity can be also applied to ranching sector (likely to be affected in a higher extend by parasitic illnesses) and to the 242,000 hectares devoted to agriculture (it shall particularly benefit corn and beetroot cultivations and damage cereal cultivations), which can has the duration of harvest reduced and sowing and harvest times modified.
In the tourist sector, a change in the demand and an intensification of the interseasonal tourism is expected. It is conditioned by affections likely to be suffered from by the different settlements and coastal infrastructures (35 beaches in the Basque Country) which might result in changes in geographic and tourist space.
Referring to human health, an increase of morbid mortality and of acute respiratory episodes, especially allergies, is expected. These episodes shall intensify as a result of extension of pollination period and the number of hot and dry days which promote environmental charge (southern region being the most affected), which shall mainly affect the sensitive population, like children and old people (in 2020 the 25% of population shall be older than 65). Changes in infectious illnesses passed on by mosquitoes and ticks, and an alteration of comfort and wellbeing conditions are expected. Finally, as a result of the increase of temperature, tropospheric ozone concentration shall also increase, especially during summer, with the subsequent worsening of air quality. This situation shall intensify in anticyclone situations in which high temperatures, scarce cloud coating and not much air predominate (situations which, predictably, due to climate change, shall happen more frequently).
Finally, in transport (15 harbours in constant expansion and reconversion of activities as well as two large sea ports), energy (468 km electrical network, 3,700 km gas distribution, 103 water power stations), town planning/building and services sectors (252 km of coast and 700 km of rivers with different distributions of urban settlements), the main impact is the increase of danger associated to weather phenomena and the increase of risk associated to structural integrity of different infrastructures, increasing the vulnerability of financial sector and insurers. The changes in the energy demand and in the supply sources (promotion of renewable ones) or the changes in the habitability conditions of the buildings are other expected impacts.
[1]: There are not significant differences between the different climate regions of the Basque Country, although the decrease of rainfall might be more evident in middle and southern regions than in the Atlantic basin.
[2]: Collected in ECCE project: preliminary evaluation of impacts in Spain because of climate change.
[3]: Aforementioned Report, "Generation of regionalized scenes of climate change for Spain".
[4]: As monthly averages.
[5]: University of Cantabria, Department of Sciences and Technique of Water and Environment, Impact on the coastal resources because of climate change, 2006.
