Glacier Change and Human VulnerabilityPresentation Transcript
IGS-BPRC Meeting, Ohio State University, 17 August 2010
GLACIER RECESSION & HUMAN VULNERABILITY IN THE CORDILLERA BLANCA, PERU B.G. Mark (1) , J. Bury (2), J.M. McKenzie (3), T. Condom (4), M. Baraer (3), Adam French (2), K.I. Huh (1), Sarah Fortner (1) and Ricardo Jesus Gomez (5) (1) Geography & BPRC, Ohio State University, (2) Environmental Studies, UCSC, (3) Earth and Planetary Sciences, McGill University, (4) Institut de Recherche pour le Développement, France; (5) Unidad de Glaciologia y Recursos Hidricos, Peru http://www.water4people.org/
Sarah Fortner (Postdoc)
Nathan Stansell (Postdoc)
Lonnie & Ellen Mosley Thompson
W. Berry Lyons
Kyung In Huh (PhD)
Jeff LaFrenierre (PhD)
Michel Baraer (PhD)
Adam French (PhD)
Ing. Ricardo J. Gomez
Ing. Marco Zapata
Unidad de Glaciologia y Recursos Hidricos
Tropical Andean Glaciers 71% in Peru 22% in Bolivia 4% in Ecuador 3% in Colombia ~1% Venezuela Source-J. Bury UC-Santa Cruz NASA Worldwind
Cordillera Blanca Peru Huandoy (6395 m)
Most glacierized of tropical mountains
Millennial-scale history of intensive use
Glacier-fed runoff to coastal desert cities (~15 million)
Sensitive to shifting climate
Source-J. Bury UC-Santa Cruz NASA Worldwind http:// newark.osu.edu/facultystaff/personal/dleavell/Pages/default.aspx
Regional climate model PDF of annual temperature in the Andes for 1961-90 (blue) and 2071-2100 (green-B2, red-A2) Mean temperature change (2071-2100 minus 1961-90) as simulated with PRECIS (Urrutia & Vuille, 2009) B2 scenario A2 scenario
~25% of glacierized area has receded since 1970
~20% Rio Santa annual flow from net glacier melt (~40% in dry season)
Future concern: sustainable water (quantity & quality)
Source-J. Bury UC-Santa Cruz NASA Worldwind Rio Santa
Interdisciplinary Research Objectives & Methods
Quantify glacial volume changes
LiDAR, photogrammetry, radar
(2) Evaluate impact of glacier melt on water quantity & quality
Discharge trend analyses
Multi-scale hydrochemical mixing
(3) Evaluate livelihood adaptation and change
Glacier tributaries Case-study watersheds Discharge Station Colcas Los Cedros Paron Llanganuco Chancos Querococha Pachacoto La Recreta
Tributaries to Rio Santa: Normalized annual discharge anomalies ( 1953-1997)
>20% glacier cover (n=2):
Significant increasing trend (i.e. more runoff)
Correlated (+) to temperature trend
All glacier streams (n=7):
Significant increasing trend prior to 1983
Almost significant decreasing trend after
Rio Santa at hydro power plant:
Significant decreasing trend
HBCM: distributed, multi-component mixing model at the watershed scale Baraer et al. 2009, Adv Geosci
Spatial variability of meltwater & groundwater (1) Llanganuco (2) Quilcay (3) Querococha M. Baraer
Stream flow time series analysis: test anticipated dynamic influence of glacier melt
Multi-decadal specific dry-season discharge
Mann-Kendall test of historical trends
Check new observations
Re-established stage loggers (2008-10)
Comparison to water-balance modeled phase of glacier melt impact
Simulate discharge as function of glacier change
New discharge logger prototype 1.5m 0.7m 0.1m 0.08m (int)
Water balance model discharge
Discharge simulation by glacier retreat rate ( γ) scenarios
There is no increase in discharge if γ does not increase over time, regardless of the extent of glacier cover
Even with an exponential change in the rate of glacier retreat, there still is a point at which the discharge will start to decline
Phase of glacier melt influence on discharge
Possible to predict what phase a particular watershed is in (trend in the historical discharge).
For each phase there is a unique combination of trends that can be matched from the trend analysis.
Discharge phase comparison with historic & new observations
For the majority of the studied watershed, the dry season discharge is in a decreasing phase, including La Balsa which drains the entire Callejon de Huaylas.
Basins that have glacier cover comparable to La Balsa (Pachacoto, Querococha, Colcas) are all in decline (phase three or four).
Fortner Present water quality issues in the Upper Rio Santa, Peru Mine Tailings Rio Santa
Fortner What does this mean for glacial ecosystems?
How do glaciers impact water quality?
What role do pro-glacial wetlands play?
Rio Quilcay Glacier fed headwaters Melt routed through shallow wetlands Metamorphic sedimentary rocks, sulfide deposits Large pastureland and eventual municipal water supply How is water quality impacted along flow paths from headwaters?
Discharge = ~1.2 m 3 /s, ~3/5 from NE, ~2/5 from NW
Unusual tributary in northeast Below convergence Lake feeding northwest branch
Alpine vegetation (w/o lake drainage) Wetlands Less Vegetation Lakes pH rapidly decreases downstream, then increases
Sulfide mineral oxidation tributary: Elevated concentrations of DOC, all metals (except Cu, Pb)
Fortner 1 Cameron et al., 1995; 2 Schuster, 2005 Tributary exceeds WHO drinking water standards
Silicate Weathering in Glacial Meltwater from the Cordillera Blanca Relative to specific runoff, high cation flux indicates high chemical weathering rates
Summary of insights Quantity:
Glacier melt water buffering is scale dependent
Multi-decadal decrease in Rio Santa discharge (without decreased precip) suggests increased withdrawal (i.e. demand)
Groundwater predominates the dry season stream flow
On a regional level, glacier retreat has already entered (decades ago) a phase of decreasing influence on stream discharge and that this decline should be maintained indefinitely.
Cation flux suggests tropical glaciers have high rates of chemical weathering (erosion?)
Metal concentrations already threaten water quality in Peruvian glacial melt streams
Mn,Ni, Pb, & Zn exceed World Health Drinking Water Standards in tributaries, near limits in stream
High concentrations from interaction of acidic glacial drainage with freshly exposed rocks….& biological metal oxidation
Baraer, M., J.M. McKenzie, B.G. Mark and S. Knox (2009). Characterizing contributions of glacier melt and ground water during the dry season in the Cordillera Blanca, Peru. Advances in Geosciences 22 , 41-49.
Bury, J., A. French, J. McKenzie, and B. Mark (2008). Adapting to Uncertain Futures: A Report on New Glacier Recession and Livelihood Vulnerability Research in the Peruvian Andes. Mountain Research and Development , 28(3/4): 332-333.
Bury, J., B.G. Mark, J. McKenzie, A. French, M. Baraer, K.I. Huh, M. Zapata and J. Gomez (2010). Glacier recession and human vulnerability in the Yanamarey watershed of the Cordillera Blanca, Peru. Climatic Change , forthcoming.
Fortner, S., B.G. Mark, J.M. McKenzie, J. Bury, A. Trierweiler, M. Baraer, and L. Munk (2010). Elevated stream trace and minor element concentrations in a tropical proglacial stream. Applied Geochemistry , forthcoming.
Mark, B.G. and J.M. McKenzie (2007). Tracing increasing tropical Andean glacier melt with stable isotopes in water. Environmental Science and Technology 40 (20), 6955-6960.
Mark, B.G., J. Bury, J.M. McKenzie, A. French and M. Baraer (2010). Climate Change and Tropical Andean Glacier Recession: Evaluating Hydrologic Changes and Livelihood Vulnerability in the Cordillera Blanca, Peru. Annals of the Association of American Geographers , forthcoming.