Impact of climate change on water resources in Spanish Mediterranean basins

Transcription

1 Impact of climate change on water resources in Spanish Mediterranean basins Teodoro Estrela Júcar River Basin Authority Research Institute of Water and Environmental Engineering (IIAMA), Technical University of Valencia, Miguel Ángel Pérez-Martín Research Institute of Water and Environmental Engineering (IIAMA), Technical University of Valencia,

2 Contents The climate change in the Mediterranean Region Climate Change impact on water resources in Spain: climate scenarios and methodologies. Impacts on Mediterranean Spanish River Basins Impacts on the Júcar River Basin District Main conclusions

3 Climate change in the Mediterranean Region

4 Climate Change in the Mediterranean Region Water is a strategic resource which can be threatened by climate change. The European Environment Agency (2010) states that the Mediterranean basin has experienced decreased precipitation and increased temperature over past decades, a trend projected to worsen. Changes in precipitation and temperature can lead to important changes in water resources in Mediterranean region.

5 Climate Change in the Mediterranean Region Percentage of variation for mean annual runoff in the period respect to the period Grated areas: more than 90% in the concordance of the models in the sign of change Source: Climate Change and Water, IPCC Technical Paper VI. IPPC, june 2008

6 Climate Change in the Mediterranean Region Climate change impacts can be aggravated in regions that already face frequent droughts in combination with low water resources levels and therefore imbalances between water demand and available resources.

7 Climate Change in the Mediterranean Region The European Mediterranean region is very vulnerable to possible climate changes because of the low available resources in this region for which higher temperature increases and precipitation decreases are projected (European Commission, 2009). Water Exploitation Index in the EU (expected for 2030). Source: European Environment Agency

8 Project Ensembles 2009 Application of 7 global models with A1B climate change scenarios. Application of regional models regional from medium-term ( ) to long-term ( ) Increases in temperature referred to the period Fuente: IPCC Fourth Assessment Report (AR4): WGI: Climate Change 2007: The Physical Science Basis

9 Climate Change Scenarios Scenario A1B: Increased concentration from the current 400 ppm up to 900 ppm 2100 values (predictable scenario). It implies growth in emissions up to 2050 and gradual reduction of intermediate stage between A2 and B1.

10 Ensembles 2009 results Regional models with A1B scenario Increase temperature air referred to Scenario A1B Mean results of RCM models Period Precipitation variation referred to Scenario A1B Mean results of RCM models Period

11 Ensembles 2009 results Regional models with A1B scenario Increase temperature air referred to Scenario A1B Mean results of RCM models Period Precipitation variation referred to Scenario A1B Mean results of RCM models Period

12 Impact of Climate Change on water resources in Spain: climate scenarios and methodologies.

13 Preliminary assessments of Climate Change impacts in Spain Preliminary assessment reports on climate change impacts in Spain show: Decreases in mean values for water resources are expected. For a decrease of 5% in mean annual precipitation and an increase of 1ºC in mean annual temperature, a decrease between 9 and 25% in runoff is expected depending on the river basin districts. The most critical Spanish areas are arid and semiarid ones where water scarcity and drought problems are greater.

14 Impact on water resources Reduction of the total runoff in scenario: increase of 1 º C of temperature Reduction of the total runoff in scenario: increase of 1 C of temperature and decrease of 5% of precipitation Source: Water in Spain, Ministry of Environment (2000)

15 Impact on water resources and vulnerability Impact on runoff reduction for a decrease of 5% in mean annual precipitation and an increase of 1ºC in mean annual temperature (year 2030) Vulnerability: Water Exploitation Index (quotient between water demand and water resources) in Spanish water resource systems Source: Water in Spain, Ministry of Environment (2000)

16 Spanish National Plan of Adaptation to Climate Change Spanish National Adaptation Plan on Climate Change Aim: Integration of adaptation to climate change into the planning strategy of the different socio-economic sectors in Spain The Spanish Center for Hydrographic Studies of CEDEX - a research and experimentation center for water issues has been commissioned by the Ministry of Agriculture, Food and Environment in the framework of National Adaptation Plan on Climate Change to make an assessment of the climate change impact on water resources sector: Natural water resources(cedex, 2010), Water demands (irrigation, public water supply and industry), Available resources in water resources systems Ecological status of water bodies

17 Climate Change scenarios of the Spanish National Plan of Adaptation to Climate Change The climatic data used are the climate scenarios regionalised by the Spanish State Meteorological Agency (AEMET, 2008). It combines the results of global circulation models made by various international organisations with regionalisation techniques at the local level. The selected emission scenarios (A2 and B2) are part of the set of greenhouse gas emission scenarios established by the IPCC in 2000.

18 AEMET, 2008 Climate Change scenarios of the Spanish National Plan of Adaptation to Climate Change

19 Climate change and water resources in Spain The main variables of the hydrological cycle (soil moisture, recharge to the aquifers, runoff, ) have been simulated using the SIMPA distributed hydrological model (Ruiz, 1998). Monthly runoff maps Monthly precipitation and potential evapotranspiration maps

20 Climate change and water resources in Spanish River Basins Percentage of water resources decrease at long term: for scenario A2 (taken from Estrela et al, 2012). Source of data. CEDEX(2010)

21 Impact on water resources in Mediterranean Spanish river basins

22 Climate change and water resources in Mediterranean Spanish river basins River Basin District Period Scenario A2 Scenario B2 The impact of climate change on water resources in all the Mediterranean basins (except for the Internal river basins in Catalonia) is greater than the mean values for the whole of Spain. The impact is greater in the basins located in the southern part of the country. Internal river basins in Cataluña mean annual runoff mean annual runoff Ebro Balearic Islands Júcar Segura Internal river basins in Andalusia Spain Variation of runoff (%) for Mediterranean Spanish river basin districts in the periods , and with regard to the control period of Source of data: CEDEX (2010)

23 Water Exploitation Index in Spanish River Basins River Basin Water resources (hm 3 /year) Total demand (hm3 /year) Current Water Exploitation Index (WEI) Water resources change Scenario A2 Water Exploitation Index (WEI) MIÑO-SIL 11, % -12% 5.5% GALICIA-COSTA 12, % -12% 7.4% CUENCAS INTERNAS PAIS VASCO 1, % -16% 22.5% CANTABRICO 16, % -16% 5.3% DUERO 13,179 3, % -17% 35.0% TAJO 10,075 2, % -19% 32.7% GUADIANA 4,473 2, % -27% 71.5% GUADALQUIVIR 7,087 3, % -28% 66.0% CUENCA MEDITERRANEA ANDALUZA 2,330 1, % -30% 82.3% GUADALETE Y BARBATE 1, % -30% 37.1% TINTO, ODIEL Y PIEDRAS % -30% 37.5% SEGURA 762 1, % -21% 300.3% JUCAR 3,357 2, % -18% 107.1% EBRO 16,202 7, % -14% 50.5% CUENCAS INTERNAS DE CATALUÑA 2,603 1, % -4% 53.9% ISLAS BALEARES % -15% 52.5% ISLAS CANARIAS % -32% 144.9% España 105,076 30, % -17% 34.8%

24 Water Exploitation Index in Spanish River Basins Current Water Exploitation Index (WEI) Water Exploitation Index (WEI) Scenario A2

25 Water Exploitation Index in Spanish River Basins Major WEI percentage increases take place in the river basins with the greatest current WEI. As a consequence the most stressed river basins will aggravate its situation.

26 Impact on water resources in the Júcar River Basin District

27 Climate Change Impacts in Júcar RBD Location of Jucar River Basin District Mean annual precipitation in Jucar River Basin District Variation of precipitation in period 1980/ /09 respect to Precipitación (mm) en la DHJ precipitation in period 1940/ / mm Año Precipitación anual Media 1940/ /09 Media 1980/ /09

28 Climate Change impacts in Júcar RBD Precipitation Mean ( ) Mean ( ) Mean ( ) 14 Temperature Mean ( ) Mean ( ) Precipitation (mm) Year Temperature (ºC) Year St reamflow Mean ( ) Mean ( ) 1600 Streamflow (hm3) Year CC impacts in the upper river basins draining to Alarcon and Contreras reservoirs

29 Climate Change Impacts in Júcar RBD Future climate using AR4 scenarios has been characterised in the Júcar RBD by Chirivella (2010) in Technical University of Valencia, showing that: the scenarios AR3 collected in AEMET (2008) reproduce correctly the temperature in the Júcar River Basin District for the control period ( ) but not the precipitation. Additionally, Chirivella (2010) performs a climatic regionalisation obtained with dynamic downscaling in two stages (first for the whole Iberian Peninsula and second, using these results above as boundary conditions on the Júcar RBD territory), observing a clear improvement:

30 Climatic regional model RegCM3 Emission Scenario: A1B Global model downscaling: ECHAM5 Regional model: RegCM3 Historic control period: Simulation period: Coarse grid Nested grid

31 Climate Change Impacts in Júcar RBD The predicted impact on water resources in the Júcar River Basin District means a reduction of 21% for the period over the control period This reduction is significantly higher than that obtained with the AEMET(2008) scenarios used by CEDEX (2010): 5% with A2 and 12% with B2 over the control period These differences can have its explanation in the combination of two facts: different CC scenarios (A1B) and use of the dynamic downscaling to represent the climate variables.

32 Conclusions

33 Main conclusions The Mediterranean region is one of the most affected regions in the world by the climate change impact on water resources. The impact on water resources is greater in the river basin districts located in the southern part of the Spain which are the most stressed ones, what will aggravate their current situation. The values of the reductions of water resources depend on the climate change scenarios and the global and regional models used. The predicted impact on water resources with the latest studies in the Mediterranean Júcar River Basin District, means a reduction of 21% for the period