1 Climate Warming & California’s Water Future Jay R. Lund, Richard E. Howitt, Marion W. Jenkins, Tingju Zhu, Stacy K. Tanaka, Manuel Pulido, Melanie Taubert, Randall Ritzema, Inês Ferreira, Sarah Null Civil & Environmental Engineering Agricultural & Resource Economics University of California, Davis http://cee.engr.ucdavis.edu/ faculty/lund/CALVIN/
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1 Climate Warming & California’s Water Future Jay R. Lund, Richard E. Howitt, Marion W. Jenkins, Tingju Zhu, Stacy K. Tanaka, Manuel Pulido, Melanie Taubert,
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Climate Warming & California’s Water Future
Jay R. Lund, Richard E. Howitt, Marion W. Jenkins,
Tingju Zhu, Stacy K. Tanaka, Manuel Pulido,
Melanie Taubert, Randall Ritzema, Inês Ferreira, Sarah Null
Civil & Environmental Engineering
Agricultural & Resource Economics
University of California, Davis
http://cee.engr.ucdavis.edu/faculty/lund/CALVIN/
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Tantalus In Hades, thirsty Tantalus was burdened to have water rise
to his neck threatening to drown him, but receded when he stooped to drink. Above him was a boulder, threatening to crush him at some uncertain future time.
California’s water managers are similarly tantalized by prospects for quenching California’s thirsts, but contend with floods and droughts, living in a world with grave prospects of earthquakes, budgets, population growth, and climate change.
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Overview1) Major Issues
2) 2100 Population Changes
3) 2100 Climate Changes
4) CALVIN Model
5) Adaptations to the Future
6) Results
7) Conclusions
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Major Issues
Climate warming effects on California’s water supplies.
Combined population growth and climate change stress.
Could California adapt?
How well could California adapt?
What would life be like?
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2100 Population & Land Use
1. Future population and land use will greatly affect water demands.
2. With growth to 92 million (UCB), urban demands grow by ~ 7.2 maf/yr
3. Urbanization of irrigated land reduces agricultural demands by ~ 2.7 maf/yr
4. Net effect is big (+4.5 maf/yr) and economically important
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2100 Climate Changes1. Water availability changes estimated for 12
climate warming scenarios (based on LBNL).
2. Water supply impacts estimated for:
a. Major mountain inflows
b. Groundwater inflows
c. Local streams
d. Reservoir evaporation
3. Effects estimated for 113 inflows distributed throughout California
($/unit-yr) Surface Reservoir (taf) SWM2100 PCM HCM Turlock Reservoir 69 202 56 Santa Clara Aggregate 69 202 56 Pardee Reservoir 68 202 56 Pine Flat Reservoir 66 198 56 New Bullards Bar Reservoir 65 196 56 Conveyance (taf/mo) Lower Cherry Creek Aqueduct 7886 8144 7025 All American Canal 7379 7613 6528 Putah S. Canal 7378 7611 6528 Mokelumne Aqueduct 7180 7609 6301 Coachella Canal 3804 3487 3618 Colorado Aqueduct 1063 970 759 California Aqueduct 669 1823 452
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Conclusions from Results1) Important to look at climate change impacts
and adaptation in context of future water demands, and the entire range of water sources, facilities, and adaptation options. Must also allow adaptations – Optimization.
2) Climate warming’s hydrologic effects are substantiated and generalized. Magnitude comparable to water demand growth.
3) California’s system can adapt, at some cost.
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Conclusions from Results (con’t)
4) Central Valley agriculture is most sensitive to dry climate warming.
5) Southern California urban users are not very sensitive to climate warming.
6) Adaptation would be challenging. Institutional change and flexibility needed to respond to both population and climate changes.
7) Study limitations are considerable, but it behooves us to consider management and policy changes.
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Glimpse at Long-term FutureResults provides a hazy glimpse at the future of
California water management:
1) Integrated mix of many management options:Water use efficiency, conjunctive use, water transfers, reuse, desalination, …
2) Importance of local and regional actions in a statewide context
3) Long-term importance of flexibility4) Some scarcity is optimal
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Work left to do…
1) CALVIN improvements
2) Flood penalties
3) Sea level rise
4) Agronomic and land use effects in agricultural demands