A Discernible Human Influence on Global Climate

Eugenie C. Scott

A Discernible Human Influence on Global Climate

Benjamin D. Santer, Ph.D.
May 31, 2014

SkeptiCAL 2014
Oakland Asian Cultural Center
388 Ninth Street
Oakland, California


Human-caused climate change is not a hypothetical future event. It is real, and we are experiencing it in our lifetimes. Despite the compelling evidence of human effects on global climate, there is a continuing need for scientists to answer the question "How do we know it’s us?" Fingerprint studies use complex computer models of the climate system to understand how geographical patterns of temperature and moisture (and many other climatic variables) may change in response to human influences. SkeptiCAL 14The message from this body of research is that observed changes in many different (and independently-measured) aspects of the climate system cannot be explained by natural causes alone.

There are several common criticisms of IPCC and NAS "discernible human influence findings." Rather than simply dismissing such criticism, it is more powerful to perform the research necessary to determine whether the criticism has scientific validity. Scientific responses to two incorrect claims are illustrative: that "global warming stopped in 1998", and that computer models systematically underestimate the observed decadal variability of atmospheric temperature.

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