Hot, Wet, and Crowded: Phase 6 Climate Change Model Findings Climate Resiliency Workgroup April 20, 2020 Lew Linker, EPA; Gary Shenk, USGS; Gopal Bhatt, Penn State; Richard Tian, UMCES; and the CBP Modeling Team [email protected] Chesapeake Bay Program Science, Restoration, Partnership 1 Key Points in Assessment of 2025 Climate Change Risk Chesapeake Bay Program Science, Restoration, Partnership • The new 2019 climate change assessment confirms the December 2017 climate change findings with a better model, providing better understanding of underlying processes, more specific findings on nutrient speciation, CSOs, wet deposition of nitrogen, etc. • Consistent assessment of violation CB4MH Deep Channel and Deep Water nonattainment from December 2017 PSC meeting to today of about 1.4% and 1.0%, respectively, even though we’ve expanded our assessment to look at EVERYTHING in the CC analysis. Elements of Chesapeake Water Quality Climate Risk Assessment Chesapeake Bay Program Science, Restoration, Partnership Assessment of 2025 Climate Change in the Airshed Chesapeake Bay Program Science, Restoration, Partnership Airshed Key Finding: Increased wet deposition N loads under increased precipitation. Assessment of 2025 Climate Change in the Watershed Chesapeake Bay Program Science, Restoration, Partnership Watershed Key Findings: Increased precipitation volume, precipitation intensity, and evapotranspiration are major determinates of changes in loads due to climate change. (Land use change beyond 2025 also increases nutrient and sediment loads.) Precipitation Volume Increasing Chesapeake Bay Program Science, Restoration, Partnership The 1991 – Projections of rainfall increase using 2000 period trend in 88-years of annual PRISM[1] data of hydrology & nutrient PRISM (red dots) and NLDAS (blue dots) data are shown loads is the Change in Rainfall Volume 2021-2030 vs. 1991-2000 basis of Major Basins PRISM Trend decisions in Youghiogheny River 2.1% the Chesapeake Patuxent River Basin 3.3% TMDL. Western Shore 4.1% There are 30 Rappahannock River Basin 3.2% years between York River Basin 2.6% 1995 and 2025. Eastern Shore 2.5% Long term James River Basin 2.2% mean Potomac River Basin 2.8% precipitation Susquehanna River Basin 3.7% increased Chesapeake Bay 3.1% and 3.1% temperature Watershed ₒ [1] Parameter-elevation Relationships on Independent Slopes Model by 1 C. Rainfall Intensity Increasing Chesapeake Bay Program Science, Restoration, Partnership Observed trend of more Partitioning of Volume into Intensity Deciles 0.7 precipitation volume in 0.6 higher intensity events 0.5 based on a century of 0.4 observations. 0.3 0.2 0.1 0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 Source: Groisman et al., 2004 National average heavy precipitation event index (HPEI) for the entire year (annual, black), for August through October (ASO, blue), and for heavy events associated with tropical cyclones (TC, red). [Kunkel et al., 2010] 7 Summary of Changes in Nutrient Species Delivery Chesapeake Bay Program Science, Restoration, Partnership10% 10.8% Nitrogen Arrows show 8% 8.3% n relatively more e g 6% o increase in r t i N organic N & P or n 4% i s 2.6% PIP compared to e g 2% n 2.4% DIN or DIP. a h C 0% RYearainfall, C2025O2, P50 P50Year Rainfal l2055, CO2, P50 Temperature Temperature Trend rainfall and Ensemble median rainfall The TN & TP loads EnsembleYear 2 0median25 & Ytemperatureear 2050 temperature are steadily increasing from 2025 to 2055 18% under climate Phosphorus 26.6% 15% change but there 15.3% s is a greater u 12% r o h proportion of p 9% s o refractory N and P h P 6% in the total N & P n i 4.5% s 3% going forward. e g 3.1% n a 0% h C RYearainfall, C2025O2, P50 P50Year Rainfa ll2055, CO2, P50 TrendTem rainfallperatu rande EnsembleTem medianperature rainfall EnsembleYear 2 median025 & temperatureYear 2050 temperature Trend: projection of extrapolation of long-term trends Ensemble: 31-member ensemble of RCP4.5 GCMs 8 Estimates of Climate Only and Climate and Land Use Chesapeake Bay Program Science, Restoration, Partnership Marginal Differences in Freshwater Delivery Marginal Differences in Sediment Delivery 8% 24% 21.6% 6.7% Future Climate (2025 Land use) 7% 6.2% 21% 18.9% Future Climate & Land use 6% 18% 4.8% 14.3% 5% 4.5% 15% 12.7% 3.9% 4% 3.7% 12% 8.5%9.2% 3% 2.4%2.4% 9% 2% 6% 3.8%3.8% 1% 3% 0% 0% Marginal Differences in Nitrogen Delivery Marginal Differences in Phosphorus Delivery 16% 40% 14% 13.3% 35% 32.9% 12% 10.8% 30% 26.6% 10% 25% 8.0% 19.7% 8% 6.7% 20% 16.5% 5.6% 6% 4.7% 15% 11.8% 9.9% 4% 2.6%2.6% 10% 4.5%4.5% 2% 5% 0% 0% 2025 2035 2045 2055 2025 2035 2045 2055 Grey bar = climate only Black bar = Climate and Land Use Elements of 2025 Climate Change in the Estuary Chesapeake Bay Program Science, Restoration, Partnership Air-temperature increase: 1.06 °C Quadratic function Flow (Boon et al. 2013) 2.4% Increase Nitrogen Load 2.6% Increase Probabilistic Phosphorus Load method 2025 Sea (Kopp et al 4.5% Increase Level 2014) Rise: Sediment Load 0.22m 3.8% Increase Phase 6 Watershed Model Open boundary T: + 0.95 °C; S: + 0.18 psu (Thomas et al., 2017) Model: CH3D-ICM 10 400m-1km Resolution Bottom DO Change: 1995 to 2025 Chesapeake Bay Program Science, Restoration, Partnership Keeping all other factors constant, sea level rise and increased watershed flow reduce hypoxia in the Bay, but the predominant influence are the negative impacts of increased water column temperature. Sea Level Rise Watershed Flow Increased Temp. All Factors 11 Summer (Jun.-Sep.) Hypoxia Volume (<1 mg/l) 1991- 2000 in the Whole Bay Under 2025 WIP3 Condition 2 Base Loading SLR Heat Flow All ) 3 1.22 1.14 1.06 1.02 1.00 1 0.91 DO solubility DO 48%solubility 48% RespirationRespiration Hypoxia volume (km volume Hypoxia 43%43% StratificationStratification 9%9% 0 12 12 Elements of Hypoxia Volume Change: 1995 - 2025 Chesapeake Bay Program Science, Restoration, Partnership Heat flux 20% Sea level Nutrient rise loading 4.5% 11% 12% All factors: Hypoxia 13 Summary Hypoxia volume change by 2025 Chesapeake Bay Program Current Climate Change Only Scenarios Science, Restoration, Partnership Air-temperature Sea Level Rise: 0.22m increase: 1.06 °C Flow Tidal wetland change +2.4% est. 2025 TN +2.6% est. 2025 TP +4.5% est. 2025 Sediment +3.8 est. 2025 Open boundarydelta T: + 0.95 °C; delta S: + 0.18 psu (Thomas et al., 2017) 14 Scenarios for Estimated Future Land Use and Chesapeake Bay Program Science, Restoration, Partnership Estuarine Practices for 2035, 2045, and 2055 Oyster aquaculture expansion Land use change 7 times the calibration by 2025 Up to 1% increase in TN and 2% in TP Tidal wetland change 15 The CBP Climate Change Assessment Achievement of Deep Channel DO water quality standard expressed as a incremental increase over the PSC agreed to (December 2017; July 2018) 2025 nutrient targets for growth and Conowingo Infill 2025 Climate 2035 Climate 2035 Climate 2045 Climate 2045 Climate 2055 Climate 2055 Climate 2025 Land Use 2025 Land Use 2035 Land Use 2025 Land Use 2045 Land Use 2025 Land Use 2055 Land Use 204TN 208TN 209TN 212TN 213TN 220TN 222TN 14.0TP 14.6TP 14.7TP 15.4TP 15.7TP 16.7TP 17.1TP 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 CB DO Deep DO Deep DO Deep DO Deep DO Deep DO Deep DO Deep Segment State Channel Channel Channel Channel Channel Channel Channel CB3MH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% CB4MH MD 1.4% 2.9% 3.1% 4.5% 5.2% 6.9% 8.2% CB5MH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% CB5MH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% POTMH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% RPPMH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% ELIPH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% CHSMH MD 1.1% 1.6% 1.6% 2.2% 2.2% 3.3% 3.3% Achievement of Deep Water DO Water Quality Standard Achievement of Deep Water DO water quality standard expressed as a incremental increase over the PSC agreed to (December 2017; July 2018) 2025 nutrient targets for growth and Conowingo infill 2025 Climate 2035 Climate 2035 Climate 2045 Climate 2045 Climate 2055 Climate 2055 Climate 2025 Land Use 2025 Land Use 2035 Land Use 2025 Land Use 2045 Land Use 2025 Land Use 2055 Land Use 204TN 208TN 209TN 212TN 213TN 220TN 222TN 14.0TP 14.6TP 14.7TP 15.4TP 15.7TP 16.7TP 17.1TP 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995 CB DO Deep DO Deep DO Deep DO Deep DO Deep DO Deep DO Deep Segment State Water Water Water Water Water Water Water CB3MH MD 0.1% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% CB4MH MD 1.0% 1.6% 1.6% 2.0% 2.1% 2.6% 2.9% CB5MH MD 0.5% 0.9% 1.0% 1.3% 1.3% 1.6% 1.6% CB5MH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% CB6PH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% CB7PH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% PATMH MD 0.0% 0.7% 0.7% 2.0% 2.2% 3.0% 3.0% MAGMH MD 0.0% 0.0% 0.0% 0.2% 0.2% -0.2% 0.4% SOUMH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% SEVMH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% PAXMH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.1% 0.1% POTMH MD 0.1% 0.3% 0.4% 0.7% 0.7% 0.9% 1.0% RPPMH VA 0.2% 1.2% 1.4% 1.7% 1.8% 1.9% 1.9% YRKPH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% ELIPH VA 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% SBEMH VA 0.0% 0.0% 0.0% 0.5% 0.6% 3.3% 4.0% CHSMH MD 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% EASMH MD 0.1% 0.2% 0.2% 0.4% 0.5% 0.5% 0.5% Achievement of Open Water DO Water Quality Standard 2025 Climate 2035 Climate 2035 Climate 2045 Climate 2045 Climate 2055 Climate 2055 Climate 2025 Land Use 2025 Land Use 2035 Land Use 2025 Land Use 2045 Land Use 2025 Land Use 2055 Land Use 204TN 208TN 209TN 212TN 213TN 220TN 222TN 14.0TP 14.6TP 14.7TP 15.4TP 15.7TP 16.7TP 17.1TP 1993-1995 1993-1995 1993-1995 1993-1995 1993-1995