Climate Change and Great Lakes Natural Systems. Climate Change and Water in the Great Lakes Region, ARC Webinar October 21, 2008

Transcription

1 Climate Change and Great Lakes Natural Systems Linda Mortsch Adaptation and Impacts Research Division, Environment Canada Climate Change and Water in the Great Lakes Region, ARC Webinar October 21, 2008 Outline of today s talk What does climate change mean for the Great Lakes Basin? Climate change scenarios Projected water level changes Wetland vegetation, bird, and fish community response to water level scenarios 1

2 Projected changes in climate for the Great Lakes Basin ( observed) Airshed Effects: Increase in air temperatures Increase in precipitable water in warmer atmosphere Change in frequency and intensity of storms Nearshore Effects: Increase in water temperature Increase in evaporation Inlake Effects: Increase in water temperature Higher evaporative losses from lakes Less ice cover (shorter duration) Watershed Effects: Warmer air temperatures More precipitation (decreases in key seasons) Less winter precipitation as snowfall and more rain Less snowpack More intense precipitation events Increase in evapotranspiration GCM Great Lakes Basin Climate Change Scenarios: temperature (T- o C) & precipitation change (P-%) for 2050s relative to ANNUAL WINTER (DJF) SPRING (MAM) SUMMER (JJA) FALL (SON) HadCM3 A1FI T Warm & Wet P CGCM2 A21 T Warm & Dry P HadCM3 B22 T Not so Warm & P Wet CGCM2 B23 T Not so Warm & P Dry 2

3 Base Case Annual - daily average air temperature ( o C) Base case & 2050s climate change scenarios Source: Croley, GLERL not as warm & dry not as warm & wet warm & dry warm & wet 0 15 Base Case Annual total precipitation it ti (mm) Base case & 2050s climate change scenarios Source: Croley, GLERL not as warm & dry not as warm & wet warm & dry warm & wet

4 Base Case Annual net basin supply (mm) Base case & 2050s climate change scenarios Source: Croley, GLERL not as warm & dry not as warm & wet warm & dry warm & wet Evaporation exceeds precipitation 4

5 Climate change implications for hydrology Warmer air temperatures less ice cover - more evaporation from lake surface more evapotranspiration - less runoff Water levels lower Connecting channel flow lower Altered seasonal flows Lake Ontario Climate Change Scenarios, 2050s LAKE OUTFLOW STATISTICS (m 3 /s) WARM & NOT-AS WARM & WARM & NOT-AS WARM BASE CASE DRY DRY WET &WET Annual Mean (-24%) 6460 (-17%) 6170 (-21%) 7420 (-5%) CHANGE OF LAKE LEVEL FROM BASE CASE (m) Annual Winter Spring Summer Autumn Source: David Fay & Yin Fan, Environment Canada 5

6 Lake Ontario - Water Level Scenarios, 2050s 76.0 Water Level (m, asl) Base Case Mean Maximum Minimum Climate Change Not as Warm&Wet Not as Warm&Dry Warm&Wet Warm&Dry 73.5 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Source: David Fay & Yin Fan, Environment Canada Lake Ontario - Flow Scenarios, 2050s mean Base case Flow (m3/s) maximum -- Recorded Historic minimum -- Recorded Historic Not as Warm&Wet Not as Warm&Dry 6000 Warm&Wet 5000 Warm&Dry 4000 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Source: David Fay & Yin Fan, Environment Canada 6

7 Lake Erie Climate Change Scenarios, 2050s WARM & BASE CASE DRY LAKE OUTFLOW STATISTICS (m 3 /s) NOT AS WARM & DRY WARM & WET NOT AS WARM & WET Annual Mean (-26%) 5410 (-18%) 5153 (-22%) 6263 (-5%) CHANGE OF LAKE LEVEL FROM BASE CASE (m) Annual (m) Winter (m) Spring (m) Summer (m) Autumn (m) Source: David Fay & Yin Fan, Environment Canada Lake Erie - Water Level Scenarios, 2050s Water level (m asl) Base Case Maximum Mean Minimum Climate Change Scenarios Not as Warm&Wet Not as Warm&Dry Warm&Wet Warm&Dry jan feb march april may june july aug sept oct nov dec Source: David Fay & Yin Fan, Environment Canada David Fay & Yin Fan, Environment Canada 7

8 Lake Erie - Flow Scenarios, 2050s 8500 Flow (m3/s) Basis Case Mean Maximum Minimum Climate Change Not as Warm&Wet Not as Warm&Dry Warm&Wet Warm&Dry JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Source: David Fay & Yin Fan, Environment Canada Lake Erie -Long Point Scenario Ontario Inner Bay Long Point Bay New Shore 1.48 m (IGLD85) water level decline Surface area of Inner Bay reduced by 32 % Shoreline moves from 0.2 km to greater than 2 km Lake Erie Source: Lee et al,

9 Adaptability: wetland ecosystems, wildlife habitat Water level variability maintains vegetation and bird and fish habitat climate change? prolonged high water pale brown/whitish areas flooded marsh are recently exposed sand Peter s Marsh, WI Wetland Study Sites LAKE ONTARIO Hay Bay Lynde Creek Presqu ile South Bay LAKE ERIE Dunnville Long Point Rondeau Turkey Point 9

10 Rule-based Vegetation Models DFO-GLLFAS Submerged Aquatic Vegetation Model (Depth, Fetch, Substrate) CWS-Waterloo Waterloo Emergent Vegetation Model (Depth, Duration of Flooding/Dewatering, Tolerance Range) Treed/Shrub Meadow Emergent Floating Submergent Modelling Wetland Community Response 10

11 Climate Change Assessment: Wetlands Developed a rule-based model in a GIS Based on water depth, duration of hydrologic condition and tolerance ranges of wetland vegetation to water level conditions Validated with historical wetland data Applied water level change fields from four climate change scenarios to historical annual water level time series to simulate future wetland response Used both a low and high initialization of water level conditions Long Point vegetation changes (1978) (1964) 11

12 Lake Erie wetland response As water levels declined Open water decreased Meadow marsh and treed/shrub increased Emergent decreased under low initialization and increased in lacustrine wetlands under high h initialization i i i Wetland Breeding Bird Habitat Guilds Emergent Marsh Obligates Emergent Marsh Generalists Meadow Marsh Treed/Shrub Swamp Pied-billed Grebe Red-winged Blackbird Swamp Sparrow Yellow Warbler American Coot Yellow-headed Blackbird Common Snipe Song Sparrow Common Moorhen Common Grackle Savannah Sparrow Common Yellowthroat Black Tern Sand Hill Crane Sedge Wren Great Crested Flycatcher Forster's Tern Common Yellowthroat Willow Flycatcher Least Bittern Least Flycatcher Virginia Rail Alder Flycatcher American Bittern 12

13 Bird Abundance Estimates in Emergent Marsh Habitat 12.0 Emergent Marsh Nesting Obligates 10.0 ance (per hectare) Abunda CCAF IJC y = x x Water Depth (metres) Long Point emergent nesting obligates (1978) (1964) 13

14 Fish Habitat Model Layers Calculations of Weighted Suitable Area (WSA = Σ Habitat Quantity Quality) Habitat Quality = Habitat Suitability Indices Base Case (High) (1978) Base Case (Low) (1964) Warm & Dry Warm & Dry 14

15 Implications of Climate Change Warm & Dry scenario - most severe scenario Initial water level conditions also important Wetlands transition to drier vegetation ti communities with less open water and interspersion Hydrogeomorphic form important factor in influencing wetland vegetation response Riverine vs lacustrine/protected embayments Not favourable for some wetland-dependent dependent birds Decrease in emergent breeding birds and increase in treed/shrub breeding birds Fish habitat suitability dependent on interaction between local bathymetry and other physical features Wetland geomorphology & vulnerability Drowned River Mouth Wetland Barrier Beach Wetland Open Embayment Wetland Protected Embayment Wetland 15

16 Climate Change Considerations Vulnerability to hydrologic change? Proactive planning and policy Long term costs to maintain values Restoration and management designs that are robust to variable hydrology Final Report and Website 16