Lonnie G. Thompson is a Distinguished University Professor in the School of Earth Sciences and a Senior Research Scientist in the Byrd Polar Research Center at The Ohio State University. His research has propelled the field of ice core paleoclimatology out of the Polar Regions to the highest tropical and subtropical ice fields. He and the OSU team have developed light-weight solar-powered drilling equipment for acquisition of histories from ice fields in the tropical South American Andes, the Himalayas, and on Kilimanjaro. These paleoclimate histories have advanced our understanding of the coupled nature of Earth’s climate system. Special emphasis has been placed on the El Niño and monsoon systems that dominate the climate of the tropical Pacific and affect global-scale oceanic and atmospheric circulation patterns. His observations of glacier retreat over the last three decades confirm that glaciers around the world are melting and provide clear evidence that the warming of the last 50 years is now outside the range of climate variability for several millennia, if not longer.