Assessment Development Global Change 404/504 1.IPCC AR5 2. U.S. Climate Change Science Program (CCSP) Inner Workings of Assessment Reports

Assessment Development Global Change 404/504 "assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation" (source: Reminder: Role of IPCC

Assessment Development Global Change 404/504 "The IPCC does not carry out research nor does it monitor climate related data or other relevant parameters. It bases its assessment mainly on peer-reviewed and published scientific/technical literature." (source: Reminder: Role of IPCC

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) When?

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) What?

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) What? Working Group 2 Outline Chapter 7. Food production systems and food security Food production: farming, livestock, and fisheries and their sensitivities to climate change Food production: farming, livestock, and fisheries and their sensitivities to climate change Food systems: processing, distribution, and access Food systems: processing, distribution, and access Food security and the means to achieve it Food security and the means to achieve it 4. Terrestrial and inland water systems 9. Rural Areas 11. Human health Adaptation – 4 Chapters Impacts, Risks, Vulnerabilities, and Opportunities – 3 Chapters Regions – 9 Chapters

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) Who?  258 Lead Authors and Review Editors  44 countries  65% are new

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) Who? Chapter 12: Long-term Climate Change: Projections, Commitments and Irreversibility Coordinating Lead Authors Matthew COLLINS UNITED KINGDOM Reto KNUTTI SWITZERLAND Lead Authors Julie ARBLASTER AUSTRALIA Ken CALDEIRA USA Jean-Louis DUFRESNE FRANCE Thierry FICHEFET BELGIUM Pierre FRIEDLINGSTEIN UNITED KINGDOM Xuejie GAO CHINA William GUTOWSKI USA Tim JOHNS UNITED KINGDOM Gerhard KRINNER FRANCE Mxolisi SHONGWE SWAZILAND Claudia TEBALDI USA Andrew WEAVER CANADA Michael WEHNER USA Review Editors Sylvie JOUSSAUME FRANCE Abdalah MOKSSIT MOROCCO Karl TAYLOR USA Simon TETT UNITED KINGDOM

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) ______ Why me? The nomination procedure

Assessment Development Global Change 404/504 The Fifth Assessment Report (AR5) ______ Conflict of Interest?

Assessment Development Global Change 404/504 Foundations of the AR5 Assessment: Coupled Model Intercomparison Project - Phase 5 (CMIP5) (cmmap.colostate.edu)

Assessment Development Global Change 404/504 1.IPCC AR5 2. U.S. Climate Change Science Program (CCSP) Inner Workings of Assessment Reports

Assessment Development Global Change 404/504 U.S. Climate Change Science Program Synthesis and Assessment Product 3.3 Weather and Climate Extremes in a Changing Climate (North America, Hawaii, Caribbean, and U.S. Pacific Islands) Adapted from a Public Briefing

Assessment Development Global Change 404/504 Preface Authors: Thomas R. Karl, NOAA; Gerald A. Meehl, NCAR; Christopher D. Miller, NOAA; William L. Murray, STG, Inc. Executive Summary Convening Lead Authors: Thomas R. Karl, NOAA; Gerald A. Meehl, NCAR Lead Authors: Thomas C. Peterson, NOAA; Kenneth E. Kunkel, Univ. Ill. Urbana-Champaign, Ill. State Water Survey; William J. Gutowski, Jr., Iowa State Univ.; David R. Easterling, NOAA Editors: Susan J. Hassol, STG, Inc.; Christopher D. Miller, NOAA; William L. Murray, STG, Inc.; Anne M. Waple, STG, Inc. AUTHOR TEAM FOR THIS REPORT

Assessment Development Global Change 404/504 Chapter 1 Convening Lead Author: Thomas C. Peterson, NOAA Lead Authors: David M. Anderson, NOAA; Stewart J. Cohen, Environment Canada and Univ. of British Columbia; Miguel Cortez-Vázquez, National Meteorological Service of Mexico; Richard J. Murnane, Bermuda Inst. of Ocean Sciences; Camille Parmesan, Univ. of Tex. at Austin; David Phillips, Environment Canada; Roger S. Pulwarty, NOAA; John M.R. Stone, Carleton Univ. Contributing Authors: Tamara G. Houston, NOAA; Susan L. Cutter, Univ. of S.C.; Melanie Gall, Univ. of S.C. Chapter 2 Convening Lead Author: Kenneth E. Kunkel, Univ. Ill. Urbana- Champaign, Ill. State Water Survey Lead Authors: Peter D. Bromirski, Scripps Inst. Oceanography, UCSD; Harold E. Brooks, NOAA; Tereza Cavazos, Centro de Investigación Científica y de Educación Superior de Ensenada, Mexico; Arthur V. Douglas, Creighton Univ.; David R. Easterling, NOAA; Kerry A. Emanuel, Mass. Inst. Tech.; Pavel Ya. Groisman, Univ. Corp. Atmos. Res.; Greg J. Holland, NCAR; Thomas R. Knutson, NOAA; James P. Kossin, Univ. Wis., Madison, CIMSS; Paul D. Komar, Oreg. State Univ.; David H. Levinson, NOAA; Richard L. Smith, Univ. N.C., Chapel Hill Contributing Authors: Jonathan C. Allan, Oreg. Dept. Geology and Mineral Industries; Raymond A. Assel, NOAA; Stanley A. Changnon, Univ. Ill. Urbana- Champaign, Ill. State Water Survey; Jay H. Lawrimore, NOAA; Kam-biu Liu, La. State Univ., Baton Rouge; Thomas C. Peterson, NOAA AUTHOR TEAM FOR THIS REPORT

Assessment Development Global Change 404/504 Chapter 3 Convening Lead Author: William J. Gutowski, Jr., Iowa State Univ. Lead Authors: Gabriele C. Hegerl, Duke Univ.; Greg J. Holland, NCAR; Thomas R. Knutson, NOAA; Linda O. Mearns, NCAR; Ronald J. Stouffer, NOAA; Peter J. Webster, Ga. Inst. Tech.; Michael F. Wehner, Lawrence Berkeley National Laboratory; Francis W. Zwiers, Environment Canada Contributing Authors: Harold E. Brooks, NOAA; Kerry A. Emanuel, Mass. Inst. Tech.; Paul D. Komar, Oreg. State Univ.; James P. Kossin, Univ. Wisc., Madison; Kenneth E. Kunkel, Univ. Ill. Urbana-Champaign, Ill. State Water Survey; Ruth McDonald, Met Office, United Kingdom; Gerald A. Meehl, NCAR; Robert J. Trapp, Purdue Univ. Chapter 4 Convening Lead Author: David R. Easterling, NOAA Lead Authors: David M. Anderson, NOAA; Stewart J. Cohen, Environment Canada and University of British Columbia; William J. Gutowski, Jr., Iowa State Univ.; Greg J. Holland, NCAR; Kenneth E. Kunkel, Univ. Ill. Urbana-Champaign, Ill. State Water Survey; Thomas C. Peterson, NOAA; Roger S. Pulwarty, NOAA; Michael F. Wehner, Lawrence Berkeley National Laboratory Appendix A Author: Richard L. Smith, Univ. N.C., Chapel Hill AUTHOR TEAM FOR THIS REPORT

Assessment Development Global Change 404/504 Chapter 3 – Understanding the Physical Basis Physical processes of the extreme behavior itself creating an environment conducive to extremes Physical understanding is a necessary condition for confidence in climate change projections

Assessment Development Global Change 404/504 Chapter 3 - Controversies Physical processes of the extreme behavior itself creating an environment conducive to extremes Physical understanding is a necessary condition for confidence in climate change projections

Assessment Development Global Change 404/504 Key Findings: 20 th Century  Human-induced warming has likely caused much of the average temperature increase in North America over the past 50 years.  This warming affects changes in temperature extremes such as increasing extremely warm nights and cold days and nights, lengthening of growing season and decrease in the number of frost days.  Observed changes in heavy rainfall over North America are generally consistent with observed increases in atmospheric water vapor, which has been associated with human-induced increases in greenhouse gases

Assessment Development Global Change 404/504 Key Findings: 20 th Century  It is very likely that the human-induced increase in greenhouse gases has contributed to the increase in SSTs in the hurricane formation regions. Over the past 50 years, there has been a strong statistical connection between tropical Atlantic SSTs and Atlantic hurricane activity as measured by the Power Dissipation Index (which combines storm intensity, duration and frequency). This evidence suggests a human contribution to recent hurricane activity. However, a confident assessment of human influence on hurricanes will require further studies with models and observations, with emphasis on distinguishing natural from human-induced changes in hurricane activity through their influence on factors such as historical SSTs, wind shear, and atmospheric vertical stability.

Assessment Development Global Change 404/504 Key Findings: Projected Changes  For North Atlantic and North Pacific hurricanes and typhoons: It is likely that hurricane/typhoon wind speeds and core rainfall rates will increase in response to human-caused warming. Simulations suggest: Tropical SST 1°C  o hurricane surface wind speeds  1- 8% o core rainfall rates  6 -18%. Frequency changes too uncertain for confident projection Spatial distribution of hurricanes /typhoons will likely change Storm surge levels are likely to increase due to projected sea level rise

Assessment Development Global Change 404/504 END Inner Workings of Assessment Reports

Assessment Development Global Change 404/504 Such studies have only recently been used to determine the causes of some changes in extremes at the scale of a continent. Certain aspects of observed increases in temperature extremes have been linked to human influences. The increase in heavy precipitation events is associated with an increase in water vapor, and the latter has been attributed to human-induced warming. No formal attribution studies for changes in drought severity in North America have been attempted. There is evidence suggesting a human contribution to recent changes in hurricane activity as well as in storms outside the tropics, though a confident assessment will require further study. SYNOPSIS North American Attribution Studies It is well established through formal attribution studies that the global warming of the past 50 years is due primarily to human-induced increases in heat trapping gasses. Global Attribution Studies

Assessment Development Global Change 404/504 In the future, with continued global warming, heat waves and heavy downpours are projected to further increase in frequency and intensity. Substantial areas of North America are likely to have more frequent droughts of greater severity. Hurricane wind speeds, rainfall intensity, and storm surge levels are projected to increase. The strongest cold season storms are likely to become more frequent, with stronger winds and more extreme wave heights. Current and future impacts resulting from these changes depend not only on the changes in extremes, but also on responses by human and natural systems. SYNOPSIS Future Projections

Assessment Development Global Change 404/504 Key priorities for improving our understanding of climate and weather extremes in a changing climate: 1. The continued development and maintenance of high quality climate observing systems will improve our ability to monitor and detect future changes in climate extremes. 2. Efforts to digitize, homogenize, and analyze long-term observations in the instrumental record with multiple independent experts and analyses improve our confidence in detecting past changes in climate extremes. 3. Weather observing systems adhering to standards of observation consistent with the needs of both the climate and the weather research communities improve our ability to detect observed changes in climate extremes. 4. Extended reconstructions of past climate using weather models initialized with homogenous surface observations would help improve our understanding of strong extra-tropical cyclones and other aspects of climate variability.

Assessment Development Global Change 404/ The creation of annually-resolved, regional-scale reconstructions of the climate for the past 2,000 years would help improve our understanding of very long-term regional climate variability. 6. Improvements in our understanding of the mechanisms that govern hurricane intensity would lead to better short-and long-term predictive capabilities. 7. Establishing a globally-consistent wind definition for determining hurricane intensity would allow for more consistent comparisons across the globe. 8. Improvements in the ability of climate models to recreate the recent past as well as make projections under a variety of forcing scenarios are dependent on access to both computational and human resources. Key priorities for improving our understanding of climate and weather extremes in a changing climate:

Assessment Development Global Change 404/ More extensive access to high temporal resolution data (daily, hourly) from climate model simulations both of the past and for the future would allow for improved understanding of potential changes in weather and climate extremes. 10. Research should focus on the development of a better understanding of the physical processes that produce extremes and how these processes change with climate. 11. Enhanced communication between the climate science community and those who make climate-sensitive decisions would strengthen our understanding of climate extremes and their impacts. 12. A reliable database on damage costs, associated with extreme weather and climate events, and how best to account for changing socioeconomic conditions, including adaptation over time, would improve our understanding of losses associated with climate extremes. Key priorities for improving our understanding of climate and weather extremes in a changing climate: