Blog Archive

Wednesday, November 18, 2015


Dr. Thomas R. Karl
Director, National Center for Environmental Information
Veach-Baley Federal Building

Dear Tom,

I just wanted to express my gratitude and scientific appreciation for the critical research you and your NCEI colleagues have performed over the last several decades. You have been pioneers in many different areas: in producing observational estimates of global-scale changes in land and ocean surface temperatures, in identifying non-climatic artifacts in temperature measurements, in developing rigorous scientific methods of adjusting for such artifacts, and in accounting for the incomplete, time-varying coverage of observations. 

NCEI has made its surface temperature data sets freely and openly available to the entire climate science community, thus enabling important research on the nature and causes of climate change, climate variability, and climate model evaluation. NCEI staff have clearly and thoroughly documented each surface temperature data set that NCEI has released - in scientific publications, in presentations to policymakers and professional societies, and in extensive online material. No scientific organization has done a more thorough or transparent job in developing and analyzing observations of 20th and early 21st century changes in Earth’s climate. 

I am deeply concerned that NCEI’s science is now being subjected to Congressional scrutiny and criticism. Such scrutiny and criticism is not warranted. The leadership of the House Committee on Science, Space, and Technology should understand that science is dynamic rather than static. All observational temperature data sets have evolved in important ways over time, in tandem with improvements in the ability to identify and adjust for inhomogeneities introduced by changing measurement systems, changing measurement practices, and changes in the spatial coverage of measurements. This is true not only for surface temperature data sets, but also for measurements of the heat content of the world’s oceans, and for satellite-based estimates of temperature change in Earth’s lower and upper atmosphere. Evolution of observational temperature data sets is a normal, on-going scientific process. It is not evidence of non-scientific behavior.

If our country is to take informed decisions on how to address problems arising from human perturbations to the climate system, we need access to the best-available scientific information on how Earth’s climate has actually changed. NCEI provides such critically important information to the scientific community, policymakers, and the public. You and your NCEI colleagues deserve our sincere thanks and our continued support.  

With best regards,

Ben Santer

Distinguished Member of Scientific Staff, Lawrence Livermore National Lab
Member, U.S. National Academy of Sciences   

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