Climate Change and Impact on Water Resource Planning Eugene S. Takle Certified Consulting Meteorologist Director, Climate Science Initiative Professor of Atmospheric Science Department of Geological and Atmospheric Sciences Professor of Agricultural Meteorology Department of Agronomy Iowa State University Ames, Iowa 50011 gstakle@iastate.edu ASCE Environmental & Water Resources Conference Ames, Iowa 25 March 2010

Outline Iowa precipitation trends of the 20th Century Scientific basis for future climate change Projected future global and regional changes in climate Impacts of climate change on water resources management

Observed Trends in Iowa Precipitation

State-Wide Average Data

State-Wide Average Data 37.5” 31.5” 19% increase

State-Wide Average Data Totals above 40” 8 years 2 years

State-Wide Average Data

Cedar Rapids Data 28.0” 32% increase 37.0”

Cedar Rapids Data 51% increase 11.8” 7.8”

Cedar Rapids Data 34% increase 20.2” 26.8”

“One of the clearest trends in the United States observational record is an increasing frequency and intensity of heavy precipitation events… Over the last century there was a 50% increase in the frequency of days with precipitation over 101.6 mm (four inches) in the upper midwestern U.S.; this trend is statistically significant “ Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Cedar Rapids Data 57% increase 6.6 days 4.2 days

Years having more than 8 days Cedar Rapids Data Years having more than 8 days 11 2 57% increase 6.6 days 4.2 days

State-Wide Average Data

D. Herzmann, Iowa Environmental Mesonet

Iowa Agricultural Producers’ Adaptations to Climate Change Longer growing season: plant earlier, plant longer season hybrids, harvest later Wetter springs: larger machinery enables planting in smaller weather windows More summer precipitation: higher planting densities for higher yields Wetter springs and summers: more subsurface drainage tile is being installed, closer spacing, sloped surfaces Higher humidity: more spraying for pathogens favored by moist conditions, more problems with fall crop dry-down, wider bean heads for faster harvest due to shorter harvest period during the daytime.

Great Flood of 1993 in the US Midwest: A New “Great Lake” Historical Data indicate this should happen about once every 500 years Lakshmi, V., and K. Schaaf, 2001: Analysis of the 1993 Midwestern flood using satellite and ground data. IEEE Trans. Geosci & Remote Sens., 39, 1736-1743.

Projected Future Trends in Iowa Precipitation

“The future isn’t what it used to be” Yogi Berra

NASA http://data.giss.nasa.gov/gistemp/graphs/

Global Mean Surface Temperature http://www.ncdc.noaa.gov/img/climate/research/2008/ann/global-jan-dec-error-bar-pg.gif

Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009.

Global Carbon Emissions (Gt) Actual emissions are exceeding worst case scenarios projected in 1990

More environmentally friendly Energy intensive Balanced fuel sources More environmentally friendly If current emission trends continue, global temperature rise will exceed worst case scenarios projected in 2007 Consider A1B FI =fossil intensive IPCC Fourth Assessment Report Summary for Policy Makers

Source: Jerry Meehl, National Center for Atmospheric Research From Jerry Meehl This slide shows the time evolution of globally averaged surface air temperature from multiple ensemble simulations of 20th century climate from the NCAR Parallel Climate Model (PCM) compared to observations. The simulations start in the late 19th century, and continue to the year 2000. The temperature scale at left is in degrees Centigrade, and temperature anomalies are calculated relative to a reference period averaged from 1890 to 1919. The black line shows the observed data, or the actual, recorded globally averaged surface air temperatures from the past century. The blue and red lines are the average of four simulations each from the computer model. The pink and light blue shaded areas depict the range of the four simulations for each experiment, giving an idea of the uncertainty of a given realization of 20th century climate from the climate model. The blue line shows the average from the four member ensemble of the simulated time evolution of globally average surface air temperature when only "natural" influences (solar variability and volcanic eruptions) are included in the model. Therefore, the blue line represents what the model says global average temperatures would have been if there had been no human influences. The red line shows the average of the four member ensemble experiment when natural forcings AND anthropogenic influences (greenhouse gases including carbon dioxide, sulfate aerosols from air pollution, and ozone changes) are included in the model. Note that this model can reproduce the actual, observed data very well only if the combined effects of natural and anthropogenic factors are included. The conclusion that can be drawn is that naturally occuring influences on climate contributed to most of the warming that occurred before WWII, but that the large observed temperature increases since the 1970s can only be simulated in the model if anthropogenic factors are included. This confirms the conclusion of the IPCC Third Assessment Report that most of the warming we have observed in the latter part of the 20th century has been due to human influences. Source: Jerry Meehl, National Center for Atmospheric Research

IPCC 2007

December-January-February Temperature Change 7.2oF 6.3oF A1B Emission Scenario 2080-2099 minus1980-1999

IPCC 2007

June-July-August Temperature Change 4.5oF A1B Emission Scenario 2080-2099 minus1980-1999 5.4oF

June-July-August Temperature Change 4.5oF A1B Emission Scenario 2080-2099 minus1980-1999 5.4oF Not the direction of current trends

IPCC 2007

Low confidence in model projection of summer precipitation IPCC 2007

IPCC 2007

Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Low confidence Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Trend of increase in occurrence of heavy precipitation over the 20th C is consistent with increasing GHG concentrations. Frequency of intense precipitation events is likely to increase in the future. Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

The planet is committed to a warming over the next 50 years regardless of political decisions Necessary Adaptation Necessary Adaptation Possible Mitigation Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

The planet is committed to a warming over the next 50 years regardless of political decisions Necessary Adaptation Necessary Adaptation Possible Mitigation Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Relationship of Streamflow to Precipitation in Current and Future Climates

Projected Changes* for the Climate of the Midwest Temperature Longer frost-free period (high) Higher average winter temperatures (high) Fewer extreme cold temperatures in winter (high) Fewer extreme high temperatures in summer in short term but more in long term (medium) Higher nighttime temperatures both summer and winter (high) More freeze-thaw cycles (high) Increased temperature variability (high) Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but model inconclusive *Estimated from IPCC reports

Projected Changes* for the Climate of the Midwest Precipitation More (~10%) precipitation annually (medium) Change in “seasonality”: Most of the increase will come in the first half of the year (wetter springs, drier summers) (high) More water-logging of soils (medium) More variability of summer precipitation (high) More intense rain events and hence more runoff (high) Higher episodic streamflow (medium) Longer periods without rain (medium) Higher absolute humidity (high) Stronger storm systems (medium) More winter soil moisture recharge (medium) Snowfall increases (late winter) in short term but decreases in the long run (medium) Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but model inconclusive *Estimated from IPCC reports

Use of Regional Climate Modeling for Design and Decision-Making: North American Regional Climate Change Assessment Program

Global models lack regional detail North America coastlines and terrain at typical global climate model resolution used for the IPCC 3rd and 4th Assessment Reports. Hadley Centre AOGCM (HadCM3), 2.5˚ (lat) x 3.75˚ (lon), ~ 280 km North America at 50 km grid spacing

NARCCAP Plan A2 Emissions Scenario GFDL CCSM HADAM3 CGCM3 MM5 RegCM3 link to EU programs CGCM3 1960-1990 current 2040-2070 future Provide boundary conditions MM5 Iowa State/ PNNL RegCM3 UC Santa Cruz ICTP CRCM Quebec, Ouranos HADRM3 Hadley Centre RSM Scripps WRF NCAR/ Note: AGCM time slices to be included, too. Initial phase involves driving RCMs with reanalysis output. Reanalyzed climate , 1979-2000

ISU Climate Science Initiative is now running four models NARCCAP Plan A2 Emissions Scenario GFDL CCSM HADAM3 link to EU programs CGCM3 1960-1990 current 2040-2070 future Provide boundary conditions MM5 Iowa State/ PNNL RegCM3 UC Santa Cruz ICTP CRCM Quebec, Ouranos HADRM3 Hadley Centre RSM Scripps WRF NCAR/ ISU Climate Science Initiative is now running four models Note: AGCM time slices to be included, too. Initial phase involves driving RCMs with reanalysis output. Reanalyzed climate , 1979-2000

Iowa State University Climate Science Initiative ISU/CSI is the only organization in the world running four different regional climate models for science, impacts and adaptation Climate change impacts and adaptation Streamflow in the UMRB Subsurface tile drainage flow Pavement performance Building design standards Soil carbon Crop growth http://climate.agron.iastate.edu/ or Google ISU CSI

Iowa Environmental Mesonet Collects over 400,000 observations per day Serves out data to thousands of users each day Receives over 10,000,000 web hits per day http://mesonet.agron.iastate.edu/

Summary There is no scientifically defensible explanation for atmospheric warming, increase in ocean heat content, and loss of ocean and land ice over the last 40 years other than increase of anthropogenic greenhouse gases Climate challenges to water resource management are most evident in extreme events Changes of extremes are more evident than changes in means Global and regional climate models have much to offer for understanding future Midwest water resource management adaptation strategies The Iowa Environmental Mesonet provides a wealth of environmental data relative to water resource management

For More Information North American Regional Climate Change Assessment Program: http://www.narccap.ucar.edu/ For current activities on the ISU campus, regionally and nationally relating to climate change see the Climate Science Initiative website: http://climate.agron.iastate.edu/ Contact me directly: gstakle@iastate.edu Contact Chris Anderson, Assistant Director of the Climate Science Initiative, cjames@iastate.edu