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.
He then showed that the rise in carbon dioxide has been caused by the increasing worldwide combustion of fossil fuels - coal, gas and oil.
"Dr. Keeling is one of that handful of scientists whose work has brought about a change in our perception of the environment of planet Earth," wrote Stephen Schwartz, senior scientist at Brookhaven National Laboratory and one of several peers who nominated Keeling.
"The world now recognizes the global increase in atmospheric carbon dioxide concentrations resulting from fossil fuel consumption. This recognition is so universally accepted that one tends to forget that it is due to the pioneering work of a single individual."
Like Keeling, Lonnie Thompson published research so seminal as to be taken almost for granted by scientists and laypeople today.
Many reasonably informed people have heard that tropical glaciers are shrinking and that the famous ice cap on Kenya's Mt. Kilimanjaro may vanish altogether in the near future. Few know the name of the man most responsible for those findings.
The discovery several decades ago that tiny samples of ancient atmospheres are entombed in glaciers was an important step, as recognized by the Tyler Prizes given in 1996 to glaciologists Claude Lorius, Willi Dansgaard and Hans Oeschger.
It was Thompson who pioneered the study of tropical glaciers at typical altitudes of 20,000 feet, open only to extremely difficult mountaineering expeditions. Thompson has spent more than two decades drilling on mountaintop ice caps in several countries in South America, Asia and Africa.
Before Thompson, the trapped gases in glacial ice were sampled only in the polar regions, giving few clues to atmospheric changes in the most populated areas of the tropics.
Thompson's work at these dangerous altitudes has filled an important gap in documenting ancient atmospheres. In addition, his painstaking measurements have documented the rapid pace at which tropical glaciers are disappearing around the world, demonstrating the ongoing effects of global warming.
"For many scientists, [Thompson's] ice cores and the global climate histories contained within them provide the first convincing demonstration that global warming exists," wrote nominator C. Bradley Moore, vice president for research at Northwestern University.
"When he first proposed his program of drilling ice cores on tropical mountain tops, the leading glaciologists considered it completely impossible. Nonetheless, Thompson designed the equipment for drilling on mountaintops around the world ... transporting ice cores to his unique facilities in Columbus, Ohio. His expeditions stretch the limits of human endurance and capability," Moore wrote.
G.J. Wasserburg, John D. MacArthur Professor Emeritus at the California Institute of Technology, wrote: "His efforts have been remarkable. They also represent a kind of sensible but heroic achievement. Thompson's contributions are legendary."
The Tyler Prize for Environmental Achievement is one of the premier awards for environmental science, energy and medicine.
It was established by the late John and Alice Tyler in 1973 and is awarded annually to individuals associated with world-class environmental accomplishments.
For more information on the Tyler Prize, go to: http://www.