The award, which includes a $200,000 cash prize and gold medals, will go to Charles David Keeling, professor of oceanography at the Scripps Institution of Oceanography at the University of California, San Diego, and to Lonnie G. Thompson, University Professor of Geology at Ohio State University.
On Friday, April 8, at 7 p.m., the recipients will be honored by the Tyler Prize executive committee and the international environmental community during a banquet and ceremony at the Four Seasons Hotel Los Angeles in Beverly Hills.
The day before, Thursday, April 7, at 2 p.m., the recipients will give public lectures at the Davidson Conference Center at the University of Southern California, which administers the prize.
Charles Keeling's measurements of carbon dioxide concentrations worldwide provided the most important data in support of the "greenhouse effect" theory of climate change. His record of the gradual buildup in atmospheric carbon dioxide since 1958, measured high on the mountain Mauna Loa in Hawaii, has come to be known as the Keeling curve.
Keeling developed the first instrument and the techniques to measure atmospheric carbon dioxide concentrations accurately, setting a standard for such measurements around the world.
He showed that carbon dioxide concentrations in the northern hemisphere change from month-to-month, with a maximum in May and a minimum in late October. His measurements also clearly show that the yearly average of carbon dioxide concentration has steadily increased from 315 parts per million in 1958 to 377 in 2004.
The seasonal reduction in carbon dioxide, Keeling demonstrated, was due to photosynthesis by green plants in the northern hemisphere.