Pieter P. Tans

2010 Roger Revelle Medal Winner

Pieter P. Tans was awarded the 2010 Roger Revelle Medal at the AGU Fall Meeting Honors Ceremony, held on 15 December 2010 in San Francisco, Calif. The medal is for “outstanding contributions in atmospheric sciences, atmosphere-ocean coupling, atmosphere-land coupling, biogeochemical cycles, climate, or related aspects of the Earth system.”


Pieter Tans has dedicated his scientific career to the study of the carbon cycle. He has been the leader in global monitoring of greenhouse gases in the atmosphere since joining the National Oceanic and Atmospheric Administration (NOAA) in the mid-1980s to guide the growth of the NOAA network. Through his leadership, this observation system is now unparalleled in the world, providing near–real time data of the highest quality and making these data freely available to all. These data have formed the heart of numerous publications on atmospheric carbon dioxide and other greenhouse gases and have enabled many additional modeling studies of the carbon cycle by groups from around the world.

Pieter’s accomplishments are many and varied. The following is but a sample:

During his thesis research on historical isotopic ratios of carbon dioxide (CO2) he developed a simple formalism to deal with isotopic exchange that is now universally followed in the field.

His 1990 paper with Inez Fung and Taro Takahashi (Science, 247, 1431–1438) was a landmark work that showed that it was highly likely that the “missing sink” for CO2 lay in the Northern Hemisphere terrestrial biosphere. Later innovative studies by Tans and coworkers used isotopic data to further refine this understanding. Then and now, quantification of this issue is one of the most important for climate change, but Tans and his colleagues’ analysis was the first that correctly showed the direction of the answer.

He led the strategy to deploy denser observations over continents including tall towers and aircraft profiles, which enabled the North American Carbon Program.

His often unheralded but critical support for carbon cycle research in other nations, and his inclusive approach and the transparency of his work as a whole, fostered the growth of greenhouse gas monitoring around the world. The NOAA observations, and NOAA’s development and maintenance of very accurate calibration standards, are the backbone of the Global Atmosphere Watch program of the World Meteorological Organization.

He fostered the development of the CarbonTracker system, now one of the flagships of NOAA research products. This reanalysis and visualization tool has attracted the attention and admiration of policy makers at the highest levels.

He invented one of the simplest scientific instruments ever, the AirCore. It was stimulated by the observation of decades-old air near the bottom of deep firn layers. The AirCore is a very long coil of tubing, lifted by balloon to high altitude, open at one end. During ascent the initial fill air streams out. During descent, atmospheric air streams back in while preserving, like a tape recorder, the trace gas mixing ratios encountered along the way.

Finally, while the global carbon cycle community has benefited most from Pieter’s leadership, scholarship, generosity, and persistence throughout his career, it is clear that society as a whole has benefited as well. Climate and environmental change brought on by the buildup of greenhouse gases in the atmosphere is a global problem that affects us all and will continue to affect generations to come. Pieter Tans was and continues to be the right person at the right time, guiding the world’s premier observing system, devising new ways to use and understand the data, enabling carbon cycle scientists around the world by providing free and timely access to the highest-quality data, and leading the development of carbon cycle science. He is most worthy of the Revelle Medal; it is a privilege to honor his lifetime of selfless commitment to science.

—JAMES W. C. WHITE, Institute of Arctic and Alpine Research, University of Colorado, Boulder


Thank you, Jim. I am very honored to receive this year’s Roger Revelle Medal. Revelle has always been an example to me of how a scientist can provide a service to society by helping to create awareness of important emerging environmental problems and by creating knowledge that can be important when tackling such problems. I also feel that I am living a very fortunate life. First, I am thankful to my wife for sharing her life with me and for us having raised a loving family. She has always been extremely supportive. Right after my Ph.D., we came to the United States with a toddler and a baby and did not look back. I have also been fortunate in my profession. As a student I was vaguely dissatisfied with my main subject, theoretical physics, when I found that I was looking for something more directly tangible and useful to society. In 1972 I came across a book entitled Inadvertent Climate Modification. It was a report of a 3-week study meeting hosted by the Swedish Academy of Sciences in the summer of 1970. It was a book written by committee, but despite that drawback I read it from cover to cover, making notes in the margins. Many of today’s topics were already in the report: the buildup of greenhouse gases, aerosols, land use, energy use, climate feedbacks, paleo climate, and much more. I was hooked. Soon after, an opportunity arose for a Ph.D. project on carbon-14 and carbon-13 in tree rings to try to reconstruct atmospheric CO2 going back a few centuries.

As climate scientists we now find ourselves in the situation that our subject is widely understood to be so relevant to society that many powerful interest groups feel threatened. Thus, we are facing a well-organized and well-funded campaign attacking our science and our integrity, spreading confusion and disinformation. This is not surprising, as mitigating climate change goes to the core of our energy supply system and the broader economic system. Human-made climate change demonstrates that we cannot continue business as usual. Should we ignore the deliberate lies and manipulations we face and stick purely with the science, hoping that sound judgment and compassion will eventually prevail? We are scientists, but we are also citizens. It is our civic responsibility to redouble our efforts to convey to the public clearly the urgency and the essence of the climate change problem. The kind of world we leave to our children and grandchildren depends on it. It will have to be a world that has as one of its guiding principles a Sanskrit prayer that was used as a dedication in the above mentioned 1972 book: “Oh Mother Earth, ocean-girdled and mountain-breasted, pardon me for trampling on you.”

—PIETER P. TANS, NOAA Earth System Research Laboratory, Boulder, Colorado