Future Climate Extremes: Physical and Human Dimensions Claudia Tebaldi Climate Central & NCAR Brian O’Neill NCAR November 13, 2012 CONFIDENTIAL AND PROPRIETARY Any use of this material without specific permission of UCAR-NCAR is strictly prohibited

From IPCC SREX (2012) SUMMARY FOR POLICY MAKERS 1 Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX)

The physical dimension of changing risks: Climate Extremes Coastal Flooding The human dimension of changing risks: Exposure: Spatial Population Distribution Vulnerability: Indexes and Economic Interactions 2

The physical dimension of changing risks: Climate Extremes Coastal Flooding The human dimension of changing risks: Exposure: Spatial Population Distribution Vulnerability: Indexes and Economic Interactions 3

Mechanisms responsible for changes in climate extremes 4 1)

Mechanisms responsible for changes in climate extremes 5 2)

Mechanisms responsible for changes in climate extremes 6 3)

When the shift in mean explains the most: Heat extremes : Ratio of record high vs. record low 7 Meehl et al., 2009: Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S. GRL Annual values of the ratio of record high vs. record low US average, observed

When the shift in mean explains the most: Heat extremes : Ratio of record high vs. record low 8 Meehl et al., 2009: Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S. GRL Annual values of the ratio of record high vs. record low US average, observed Long term trend

When the shift in mean explains the most: Heat extremes : Ratio of record high vs. record low 9 Meehl et al., 2009: Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S. GRL Annual values of the ratio of record high vs. record low US average, observed Long term trend Confidence interval under the assumption of no long term trend

When the shift in mean explains the most: Heat extremes : Ratio of record high vs. record low 10 Meehl et al., 2009: Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S. GRL US average, observed US average, CCSM US average, CCSM, Future

And just in case you are curious about the past year: 11 US as a whole: 7.6

When the shift in variance is more relevant: Precipitation extremes 12 Meehl et al., 2005: Understanding future patterns of increased precipitation intensity in climate model simulations. GRL Tebaldi et al., 2007: Going to the extremes. Climatic Change Tebaldi et al., 2012: Mapping model agreement on future climate projections. GRL Future Changes in Mean Precipitation Future Changes in Precipitation Intensity Green-Blue: Increase in precipitation amounts Pink-Brown: Decrease in precipitation amounts Stippling: Model consensus

Most recent simulation results: NCAR’s CCSM4 under different scenarios Changes in average temperature during the warmest three nights of the year (degrees C) by the end of the century 13 Meehl et al., 2012: Climate System Response to External Forcings and Climate Change Projections in CCSM4. J. of Climate Low Forcing – High Mitigation High Forcing – No Mitigation

Most recent simulation results: CCSM4 under different scenarios Change in Precipitation Intensity (mm/day) by the end of the century 14 Meehl et al., 2012: Climate System Response to External Forcings and Climate Change Projections in CCSM4. J. of Climate Low Forcing – High MitigationHigh Forcing – No Mitigation

The physical dimension of changing risks: Climate Extremes Coastal Flooding The human dimension of changing risks: Exposure: Spatial Population Distribution Vulnerability: Indexes and Economic Interactions 15

Changes in risk of coastal floods from storm surges as an effect of mean sea level rise 16 Tebaldi et al. 2012: Modelling sea level rise impacts on storm surges along US coasts. Envir. Res. Letters Current 100-year events (meters above Mean High Water)

Changes in risk of coastal floods from storm surges as an effect of mean sea level rise 17 Current Sea Level Rise ( ) (mm/year) -2 – 0 0 – 2 2 – 4 4 – 6 6 – 6.5

18 Future ( ) Sea Level Rise (meters)

The Battery, NY: Storm Surges (meters above Mean High Water) 19 Sandy’s surge

The Battery, NY: Storm Surges (meters above Mean High Water) 20 The 100-yr event becomes the 15-yr event by 2050

Future extremes’ changed frequencies 21 Every how many years will today’s 100-year event recur, by 2050?

By at most the end of the century 6 ft surges will be happening on average every other year, or more frequently. 22 Strauss et al., 2012: Tidally adjusted estimates of topographic vulnerability to sea level rise and flooding for the contiguous United States. Envir. Res. Letters Terrain inundated by 6ft surges

From IPCC SREX (2012) SUMMARY FOR POLICY MAKERS 23 Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX)

The physical dimension of changing risks: Climate Extremes Coastal Flooding The human dimension of changing risks: Exposure: Spatial Population Distribution Vulnerability: Indexes and Economic Interactions 24

Spatial Population Projection: Florida 25 Physical Impact Population Exposure Jones & O’Neill, in prep. Terrain inundated by 6 ft surges

Spatial Population Projection: Florida 26 Current High Growth, 2100 Medium Growth, 2100

Spatial Population Projection: Hurricane Sandy Landfall Area The Battery

28 Existing Projection, 2100 State of the art, 2007 Shortcomings:  Topography  Protected areas  Borders  Calibration Spatial Population Projection: National Gruebler et al., 2007.

29 Existing Projection, 2100 NCAR Projection, 2100 Spatial Population Projection: National Jones & O’Neill, in prep.

30 Projected Population Distribution Spatial Population Projection: Global Projected Heat Extremes Gruebler et al., 2007.

The physical dimension of changing risks: Climate Extremes Coastal Flooding The human dimension of changing risks: Exposure: Spatial Population Distribution Vulnerability: Indexes and Economic Interactions 31

Vulnerability Index 32 Income Education Human Development Index Fertility, Population Growth, Age Structure Life Expectancy Vulnerability Measuring vulnerability Separate Projections Modeled Outcomes

Human Development Index 33 Low Medium High Very High Sub-Saharan Africa India Other Dev. Ctries China Lat. Am. & Carrib. Other Indust. Ctries O’Neill et al., in prep.

Integrated Population- Economy-Technology-Science (iPETS) Model 34 Transition Countries Other Indust. Countries Other Devel. Countries Sub-Sah. Africa USA Latin America EU-27+ China India

Economic interactions 35 CESM iPETS Climate Risks e.g., Crop Production e.g., Extreme Heat, Drought

Cropland Economic Interactions: Agricultural impacts iPETS Results, Latin America region: Effect of reduced productivity on land use and food prices 36 Change in Food Price Baseline Scenario Reduced Productivity Increase in Food Price due to Reduced Productivity Million Hectares Price change (%)

Summary Projecting changes in both physical and human systems is necessary for anticipating future risks from climate change Progress requires closer integration of research on climate science and human systems 37

Acknowledgments 38 NCAR Integrated Science Program DOE Cooperative Agreement DE-FC02-97ER62402 DOE Integrated Assessment Research Program G. Meehl, G. Strand (NCAR); J. Arblaster (NCAR and CSIRO); B. Strauss, D. Adams-Smith, R. Ziemelinski (Climate Central); Chris Zervas (NOAA); Bryan Jones, Xiaolin Ren, Leiwen Jiang (NCAR); Shonali Pachauri, Regina Fuchs, Samir KC (IIASA); Michael Dalton (NOAA); Ed Balistreri (Colorado School of Mines).