potential impactsof climate change and population growth ...water supply and demand must be...

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SGCP Potential Impacts of Climate Change and Population Growth on U.S. Water Supply and Demand in the Next 50 Years Steve McNulty, Ge Sun, Jennifer Moore Myers, Erika Cohen, and Emrys Treasure Southern Global Change Program Eastern Forest Environmental Threats Assessment Center Southern Research Station USDA Forest Service, Raleigh NC

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Page 1: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Potential Impacts of Climate Change and

Population Growth on U.S. Water Supply

and Demand in the Next 50 Years

Steve McNulty, Ge Sun, Jennifer Moore Myers, Erika Cohen, and

Emrys Treasure

Southern Global Change Program

Eastern Forest Environmental Threats Assessment Center

Southern Research Station

USDA Forest Service, Raleigh NC

Page 2: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

• Forests provide the best water

quality among all land uses

• Forest lands (30% of land area)

provide >50% of water supply

in the US

• Climate change, disturbances,

population growth, urbanization

and land use change could

impact water quantity

Why is the Forest Service Interested in

Water and Climate Change?

Page 3: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Water Supply and Demand

Supply Demand

Climate Landuse

change Population

Reservoirs,

Groundwater

Facilities

Envir flow

Water price,

Economics.

Page 4: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Water Supply Stress Index

(WaSSI):

SupplyWater

DemandWater WaSSI =

(Sun et al. JAWRA, 2008 44(5):1073-1075)

Page 5: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Water Supply at Hydrologic Unit Code (HUC)

Scale (Watersheds)

= Precipitation - Evapotranspiration +

Groundwater Supply + Returnflow from Water

Users - Environmental Flow

Water Demand by Humans at HUC Watershed

Scale

= Water Use by Sector (Thermoelectric,

Commercial, Domestic, Irrigation, Livestock,

Industrial, Mining, Public Supply Use/Loss)

Definitions

Page 6: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Current Water Supply (MGD)

Water Supply0 - 100100 - 500500 - 10001000 - 20002000 - 40004000 - 80008000 - 1200012000 - 2000020000 - 60000

States

Page 7: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Current Water Demand (MGD)

ater Demand0 - 100100 - 200200 - 400400 - 800800 - 16001600 - 32003200 - 6620

States

Page 8: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Water Demand / Water Supply (WaSSI) (1974-1993)

WaSSI0 - 0.010.01 - 0.050.05 - 0.10.1 - 0.20.2 - 0.40.4 - 0.60.6 - 0.80.8 - 1>1.0

States

Page 9: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Projections

Page 10: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 11: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 12: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

• Scenario 1 = Baseline

– 1992 landcover, historic climate and water use

• Scenario 2 = Historical climate+Pop change (2050)

• Scenario 3 = Historical climate + Deforestation 10%

• Scenario 4 = Historical climate + Irrigation -10%

• Scenario 5 = climate change (HadCMSul2, CGC1)

• Scenario 6 = Climate change + Population growth

Hypothetical Scenarios Examined

Page 13: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

% Changes in Water Demand / Water Supply (WaSSI) due to:Population Growth (2050)

Ushuc.shp-7.8 - 00 - 2525 - 5050 - 100100 - 200200 - 1340.9

States_alb.shp

Page 14: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Climate Change (Hadley2)

WaSSI Change %-95.3 - -30-30 - -10-10 - 00 - 5050 - 100100 - 447.8

States

Page 15: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Climate Change (Hadley2) + Population Growth

WaSSI Change %-95.3 - -30-30 - -10-10 - 00 - 5050 - 100100 - 447.8

States

Page 16: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Climate change only (1994-2050) Climate change + Population growth

Climate Change (Hadley2)

%0

8

Climate Change (Hadley2) + Population Growth

WaSSI Change %-95.3 - -30-30 - -10-10 - 00 - 5050 - 100100 - 447.8

States

Page 17: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

National Overall Pictures

Page 18: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

National Average Water Supply and Demand

0

1000

2000

3000

4000

5000

His

torica

l His

+Pop

Cha

nge

His

+Def

ores

tHis

+Irrig

atio

n

Had

ley2

CGC1

Had

ley2

+Pop

CGC1+

Pop

Scenarios

0

0.05

0.1

WaSSI (Demand/Supply)

Supply

Demand

Demand/Supply

Page 19: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Seasonal Distribution of WaSSI

0

0.05

0.1

0.15

0.2

1 2 3 4 5 6 7 8 9 10 11 12

Month

WaSSI

Base

Population

Deforest

Irrigation

Hadley2

CGC1

Page 20: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Model Expansion

Flow Routing

Page 21: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Mississippi River Flow Under Two Climate Change Scenarios

0

50000

100000

150000

200000

250000

1974 1984 1994 2004 2014 2024 2034 2044 2054 2064 2074 20842094

Year

Canadian

Hadley2

Linear (Canadian)

Linear (Hadley2)

Page 22: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Model Expansion

WaSSI-CB (Carbon and Biodiversity)

- Applying other equations to the WaSSI database

Page 23: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 24: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Carbon

Page 25: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 26: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 27: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Biodiversity

Page 28: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 29: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 30: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 31: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Page 32: Potential Impactsof Climate Change and Population Growth ...Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale) Regardless

SGCP

Water supply and demand must be addressed together at the basin scale (upstream and downstream; and seasonal scale)

Regardless of climate change, population growth will cause waterstress problems in metropolitan areas

Climate variability will likely have a larger impact on episodic water shortages than will climate change over the next several decades

The ability to synergistically examine tradeoffs between water availability, forest carbon sequestration and biodiversity is animportant addition to our assessment capabilities

Summary