Fingerprint research seeks to improve understanding of the nature and causes of climate change. The basic strategy is to search for model-predicted patterns of climate change ("fingerprints") in observed climate records. Such studies exploit the fact that different factors affecting climate have different characteristic signatures. These unique attributes are clearer in detailed patterns of climate change than in global-mean climate information. Fingerprinting is a powerful tool for separating human and natural climate-change signals. Results from fingerprint research provide scientific support for findings of a "discernible human influence" on global climate.
Twenty-four years ago, at the time of publication of the Second Assessment Report of the Intergovernmental Panel on Climate Change, most fingerprint studies relied on surface temperature. Critics of this work argued that a human-caused fingerprint should be identifiable in many different aspects of the climate system, and not in surface thermometer records alone. Climate scientists responded to this justifiable criticism by moving beyond early "temperature only" ingerprint studies, interrogating modeled and observed changes in rainfall, water vapor, river runoff, snowpack depth, atmospheric circulation, salinity, and many other climate variables. The message of this body of work is that human-caused fingerprints are ubiquitous in the climate system.
My lecture looks back at over two decades of efforts to identify human effects on global climate. It will also address some personal lessons learned since publication of the "discernible human influence finding".
Ben Santer is an atmospheric scientist at Lawrence Livermore National Laboratory. He studies natural and human "fingerprints" in observed climate records. His early research contributed to the historic 1995 conclusion of the Intergovernmental Panel on Climate Change: "the balance of evidence suggests a discernible human influence on global climate". He served as lead author of a key chapter of that report. Since 1995, Ben has identified human fingerprints in atmospheric temperature and water vapor, ocean heat content, sea surface temperature in hurricane formation regions, and many other climate variables.
Ben holds a doctorate in Climatology from the University of East Anglia, England. After completing his Ph.D. in 1987, he spent five years at the Max-Planck Institute for Meteorology in Germany, where he worked on developing and applying climate fingerprint methods. Ben joined Lawrence Livermore in 1992.
Ben has received a number of awards for his research. These include a MacArthur Fellowship (1998) and membership in the U.S. National Academy of Sciences (2011). The most significant awards are the friendships he has made during his career. In addition to his research, he cares deeply about the communication of climate science to a wide range of audiences. He writes for the Scientific American blog and has appeared on "Late Night with Seth Meyers".
Together with Chip Duncan and Dr. Hernando Garzon, Ben is a member of "The Three Tenors of Climate Change". The Tenors are devoted to the task of improving public understanding of the science and impacts of human-caused climate change. In his spare time, Ben is an avid rock-climber and mountaineer.