Coping with International Water Conflict in Central Asia ~ Implications of Climate Change and Melting Ice in the Syr Darya Catchment *

Size: px

Start display at page:

Download "Coping with International Water Conflict in Central Asia ~ Implications of Climate Change and Melting Ice in the Syr Darya Catchment *"

Amberly McCarthy
5 years ago
Views:

1 Coping with International Water Conflict in Central Asia ~ Implications of Climate Change and Melting Ice in the Syr Darya Catchment * *: Partially funded by NOAA CORC ARCHES. Tobias Siegfried, Thomas Bernauer, Renaud Guiennet, Scott Sellars, Andrew W. Robertson, Justin Mankin, Peter Bauer-Gottwein 21 / 06 / 2010

2 Transboundary Surface Water Conflict in Central Asia Syr Darya Khazakhstan Amu Darya Tien Shan Pamir 200 km Hindukush Upstream water/hydropower energy - rich Downstream energy & fertile land - rich

3 Environmental Change and Impacts OXFAM Report 2010: The report, Reaching Tipping Point? Climate Change and Poverty in Tajikistan, says that the country s glaciers, mainly found in its Pamir Mountains..., are retreating and could lead to greater water shortages and potential disputes in the wider region in the future.

4 Environmental Change and Impacts I. Temperature II. Precipitation III. Land use IV. Infrastructure Glacier melt Seasonality of runoff Irrigated agriculture New infrastructure Short / medium-term impacts Long-term impacts Drought risk Shallow groundwater Transboundary tensions Glacial lake outbursts Persistence of flow Soil salinization Aging of existing infrastructure Mean flow Flood risk Reservoir siltation Key Concern: Climate change leads to increased water scarcity and, consequently, to more conflict between riparians

5 Environmental Change and Impacts I. Temperature II. Precipitation III. Land use IV. Infrastructure Glacier melt Seasonality of runoff Irrigated agriculture New infrastructure Short / medium-term impacts Long-term impacts Drought risk Shallow groundwater Transboundary tensions Glacial lake outbursts Persistence of flow Soil salinization Aging of existing infrastructure Mean flow Flood risk Reservoir siltation Focus on linkages: Climate - Hydrology - Land Ice components

6 Model Components GCM Output Low-frequency Variability Climate NHMM Downscaling Land Surface Hydrology T < 0 deg C Precipitation (P) Temperature (T) Ice storage Snow Storage T > 0 deg C Ice storage T > 0 deg C Actual ET Baseflow Management Model Snow / Ice melt Soil Storage Percolation Groundwater Storage Integrated systems model approach Rainfall-runoff model: Pereira Cardenal S. J., Riegels N., Berry P., Smith R., Yakovlev A., Siegfried T., Bauer-Gottwein P. (Journal of Hydrology, 2010)

7 Distribution of Glaciers in Syr Darya Catchment 50 GLIMS database glaciers in Syr Darya catchment 48 Subcatchments of hydrological model Aral Sea 46 northing 44 Chu River Headwater Kara Darya Headwater Naryn River Headwater Source: GLIMS Database easting Data on more than glaciers available in the Naryn/Syr Darya catchment (Tien Shan Mountains) Information retrieved: glacier length, mean elevation, slope

8 Glaciers - Selected Statistics 250 Distribution of glacier mean elevation in Syr Darya catchment 250 Cummulative ice volume as a function of elevation # glaciers in elevation zone ice volume [km 3 ] mean elevation [masl] mean elevation [masl] Scaling laws: Length L Volume V Assumption: Length fluctuations L = f(t,p)

9 Investigation of 2 Climate Futures 1. Get GCM trends (SRES A2 only) (location: 34 N-41 N, 73 E-85 E) Baseline and A2 Precipitation Scenarios GCM Ensemble Member Temperature [deg / 50 a] Precipitation [mm / 50 a] CNRM CM CGCM3.1(T47) GFDL CM GFDL CM GISS ER Ensemble Mean Low-frequency Variability + 3. Seasonality + 4. Daily stochasticity BL Temperature for sample catchment A2 Temperatures for sample catchment Precipitation and temperature forecasts (Baseline (BL) and A2)

10 Development of Land Ice Cover 200 BL Scenario (100 realizations) 200 A2 Scenario (100 realizations Ice volume [km 3 ] Ice volume [km 3 ] mu 2 sigma mu year 20 0 mu 2 sigma mu year Monte Carlo ensemble (100 realizations) SRES A2 Ice loss: 40% ± 5% (~50 m 3 /sec) = 5% of total runoff, approx.

11 Subcatchment Impact Assessment A: Naryn / Syr Darya B: Kara Darya C: Chu River A2 Scenario 2049 C [m 3 /s] northing 44 A B easting 0 1. Impact on selected subcatchments significant.

12 Annual Contribution from Glacier Melt to Total Runoff 2. Climate change-induced runoff increases are unlikely to mitigate the conflict over water allocation between upstream and downstream, even over the short to medium term.

13 Changes in Glacier Morphology BL Scenario A2 Scenario BL 2010 BL A A # 800 # Glacier length [km] Glacier length [km] 3. Important changes in length of glaciers translate into significantly increased dangers from glacial lake outbursts / catastrophic flooding events.

Glacier Lakes and the Danger of Outbursts Unless adequately managed through e.g. drainage, significant risk from outbursts to the downstream population.

14 Glacier Lakes and the Danger of Outbursts Unless adequately managed through e.g. drainage, significant risk from outbursts to the downstream population. Source: Najar, A. (2009) When Ice melts, Nature News Feature

15 Implications / Conclusions Glacier will remain hydrologically active over the 21st century in the Tien Shan / Hindukush mountains Climate change will not lead to a complete aridization of Central Asia. Changes in mean runoff / seasonality in runoff / persistence of flows expected, with greatly variable impacts across subcatchments. Present infrastructural developments should be reviewed in light of these findings (centralized vs. distributed infrastructural developments). Management implications need to be careful studied and collaboration between upstream and downstream actively enforced as new challenges from climate change emerge.

Climate Change Impacts on the Upstream Water Resources of the Amu and Syr Darya River Basins

Climate Change Impacts on the Upstream Water Resources of the Amu and Syr Darya River Basins March 2012 Authors W.W. Immerzeel A.F. Lutz P. Droogers Client Asian Development Bank Report FutureWater: 107