Climate Change and Potential Impacts to Water Operations Levi Brekke (Reclamation, Technical Service...

Climate Change and Potential Impacts to Water Operations

Levi Brekke (Reclamation, Technical Service Center)

Presentation for the Bighorn River System Issues Group29 July 2008, Lovell, WY

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent climate projections?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

“Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level.”

IPCC (2007) Working Group 1 Summary for Policymakers

Other Global Trends

Global Mean Air Temperature

Global averagesea level

Northern Hemispheresnow cover

Fig. IPCC (2007)

Western U.S. ClimateTemperature

1950-1997 trend (Mote et al. 2005)

Precipitation

1976-2005 trend, “annual” inches/decade (www.cpc.noaa.gov/anltrend.gif)

Bighorn Basin region:NOAA “Climate Division” data

http://www.cefa.dri.edu/Westmap/

Red = annual, blue = moving 25-year mean annual

http://www.cefa.dri.edu/Westmap/

Red = annual, blue = moving 25-year mean annual

Historical Climate Division P data:WY-04 Bighorn

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent climate projections?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

Explaining Temperature

Trends• “Attribution” Studies• Model past Climate for

two cases:– ~All past “forcings”– Only past natural

“forcings”

• Compare Results to Obs. (globally)… – Need ~All “forcings” to

explain observed

Fig. Andrea Ray

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent “climate projections”?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

Making Climate Projections:steps before global climate modeling

Econ/techstorylines

emissionscenarios

atmosphericconcentrations

climate

model

model

GCM

Fig. P. Chris Milly

• Show energy moving from equator to poles through hydrologic cycle.– Huge amounts of water and heat move around the planet – Evaporation, Ocean Currents

Global Climate Modeling objectives

More certain results: Temperature

Fig. IPCC (2007)

Atmospheric water content anomaly, 30S-30N over ocean; GFDL GCM; SMMR,SMM/I observations (Held and Soden, 2006)

More certain results:Atmospheric Water, large areas

Fig. P. Chris Milly

Less certain results:Precipitation, local/regional areas

Fig. David Yates

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent climate projections?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

Fig. IPCC (2007)

Temperature, three “scenarios”, results from multiple models

Change in mean-annual (%),2090-2099 from 1980-1999

Fig. IPCC (2007)

Precipitation, one “scenario” (A1b), results from multiple models

Downscaling: relating GCM outputs to local/regional change

• Developers– Santa Clara

University (Ed Maurer)

– Reclamation– LLNL

• Funding– Reclamation– DOE NETL

http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections/

Archive Scope

• Variables– Precip rate (mm/d)– Mean Daily Temp(°C)

• Attributes– Monthly, 1950-2099– 1/8°, contiguous U.S.

• Model Membership– projected SRES paths A1b,

A2, B1– Simulated past climate (i.e.

“20th Century Climate Experiment”)

…led to 112 projections selected for inclusion in archive

# WCRP CMIP3 Model I.D. # A1b # A2 # B1

1 BCCR-BCM2.0 1 1 1

2 CGCM3.1 (T47) 1…5 1…5 1…5

3 CNRM-CM3 1 1 1

4 CSIRO-MK3.0 1 1 1

5 GFDL-CM2.0 1 1 1

6 GFDL-CM2.1 1 1 1

7 GISS-ER 1 2, 4 1

8 INM-CM3.0 1 1 1

9 IPSL-CM4 1 1 1

10 MIROC3.2(medres) 1…3 1…3 1…3

11 ECHO-G 1…3 1…3 1…3

12 ECHAM5/MPI-OM 1…3 1…3 1…3

13 MRI-CGCM2.3.2 1…5 1…5 1…5

14 CCSM3 1…4 1…3, 5…7

1…7

15 PCM 1…4 1…4 2…3

16 UKMO-HadCM3 1 1 1

Change in mean-annual T (ºC),2041-2070 from 1971-2000,

middle change among 112 projections, at every downscaled location

Change in mean-annual P (in/yr),2041-2070 from 1971-2000,

middle change among 112 projections, at every downscaled location

Focusing on Bighorn area…

1). From website, download monthly “mean-area” Tair & P time series for all 112 projections.

2). Compute historical-to-future period changes in mean-annual, mean-area T & P for every projection. Use 1971-2000 as historical reference period.

Consider spread of projected changes foro T and P individually. (Highlighting10 and 90 percentile changes…)

2010-2039 2040-2069 2070-2099

Now consider spread of paired changes… yellow-area shows intersected 10/90 percentile ranges

2010-2039 2040-2069 2070-2099

Consider spread of paired changes in T and P

2010-2039 2040-2069 2070-2099

Consider spread of paired changes in T and P

2010-2039 2040-2069 2070-2099

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent “climate projections”?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

Potential Natural Impacts

• Based only on warming…– less snowfall, more rainfall – less snowpack, more runoff during winter – less snowpack, less runoff during spring – less snow area, more watershed participating in

winter runoff events relevant to local flood control– earlier greenup, longer growing seasons– increased crop water demand based on T increase

• But, not sure whether CO2 increases will counter/amplify

– warmer aquatic environments

Projected Runoff Impacts…“nearby” basin (Upper Missouri)

Reclamation R&D study (FY08, ongoing)

Collaboration with Univ CO, Univ AZ, NWS Missouri Basin RFC and Colorado Basin RFC

Missouri above Toston:Change in Annual T-Norms

Missouri above Toston: Change in Annual P-Norms

Missouri above Toston: Change in Annual Flow-Norms

Missouri above Toston: Change in Monthly T-Norms

Missouri above Toston: Change in Monthly P-Norms

Missouri above Toston: Change in Monthly Flow-Norms

Potential Operations Impacts

• Less “controllable” water supply if… – Increased winter runoff (decreased spring runoff)

combined with no reduction in winter flood-space causes winter runoff to be spilled rather than conserved

• Different release schedules to accommodate…– earlier greenup, longer growing seasons– Changes in crop water demand – Management of aquatic environments under warming

• Others?

Outline

1. Is climate changing?

2. Are we affecting it?

3. Can we predict it?

4. Recent “climate projections”?

5. Impacts to hydrology and operations?

6. Factoring it into longer-term planning?

No

START

Question 7)Should effects disclosure

be based on projected climate change?

Option 4:Quantitative Sensitivity Analysis…

Option 5:Quantitative Effects Analysis, where disclosure is based on a

projected climate scenario rather than continued recent climate

Option 1:No Analysis

Question 6)Is look-ahead more than

~15 to 20 years?

Significant Sensitivity?Question 1)

Is climate relevant to theproposed project?

Question 2) Is look-ahead relevanton a climate change

time scale?

Question 3) Are regional projections

of climate changeavailable?

Option 2:Literature Review…

Question 4) Do regional projections

suggest significantchange?

Question 5) Is it preferable to

follow lead of partneragency?

No

No

Yes

Yes

Yes

IPCC 2007: (a) climate is generally assessed over a 20- to 30-year period; (b) climate change is generally measured as statistical changes between periods of 10 years or longer. (http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Annexes.pdf)

Option 3:Qualitative Analysis…

Option 6:Follow lead ofPartner-Agency

END

Options 4 and 5 include the same Literature Review as in Option 3.

No

No

Don’t Know

No

Yes

Yes

Yes

Yes

No

Yes

Some scoping questions for factoring climate change into planning analyses… Reclamation has recent experience with Options 3 and 4

All Regions, TSC

MP, PN, TSC

Given: Climate projection(s) of monthly T

and P (downscaled)

Natural Responses, Social Responses,

Operational Constraints

Operations Response

Operations-dependent Response

“Bracketing” climate projections…

Analyzing Operations under Climate Change(Option 4 example, MP OCAP/ESA study)

Rainfall-runoff simulation analysis under each climate projection...

Operations modeling followed, reflecting supply changes under each projection. Delta levels, Delta water quality, and reservoir water temperature modeling

Consumptive Use modeling wasn’t done… choice was rationalized assuming that demands wouldn’t necessarily change at “district-level” given management flexibility.

No operations constraint adjustments made (e.g., monthly flood control rules, environmental/instream demands)

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Climate Projection Selection:Rationale developed for MP OCAP

• Given: available downscaled projections– http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections/

• We don’t know the “right” projections, therefore consider all CMIP3 projections as fair game.– We cannot classify emissions paths as more/less likely.– Its not obvious how to classify GCMs as better/worse.

• Gleckler et al. 2008, Reichler et al. 2008, Brekke et al. 2008

– Projections uncertainty doesn’t necessarily diminish after determining a “worse” set of GCMs and discarding their projections.

• Brekke et al. 2008

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Projection Selection Factors

1. Periods: Future and historical (planning look-ahead determines future)

2. Climate Metric: for assessing “change” relevant to study (computed for all projections)

3. Location: where “spread” of changes from all projections is assessed, relevant to study

4. Change Range: subjective, within “spread”

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Projection Selection Factors:MP OCAP Choices

1. Periods: 1971-2000, 2011-2040 (consultation horizon is through 2030)

2. Climate Metric: Period Mean-Annual Tair & P

3. Location: “Above Folsom” (sensitivity interest on change in water supply, Sierra Nev. runoff)

4. Change Range: 10 to 90 %-tile Tair, P (desire to represent broad set of possibilities)

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Implementing Selection Factors:Step 1) Survey projections

“Above Folsom”

1a. From website, download monthly Tair & P time series.

1b. Compute historical and future period “climate metrics” for every projection.

1c. Compute historical-to-future period changes in “climate metric” for every projection.

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Step 2) Identify rank-threshold Tair and P

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Step 3) Overlay rank-threshold Tair and P on scatter paired changes

http://www.usbr.gov/mp/cvo/ocapBA_2008.html#appendices, Appendix R

Result: range of future climates

represented by set of bracketing projections

Questions?

Levi Brekke

Reclamation, Technical Service Center

lbrekke@do.usbr.gov