Climate Change

I am one of the organizers of Carolina Climate Change Scientists, a cross-campus faculty group on climate change.


Here are some recent videos where I am speaking about climate change:

Videos from Clean Air Carolina Sept., 2018

Video from Center for Energy Education Oct., 2018


March 29, 2018 – My response to climate skeptic William Happer’s lecture in Chapel Hill

William Happer presented in Chapel Hill on Sept. 12, 2017. I have responded to his many points from the perspective of a mainstream climate scientist. Please see the video of his lecture, his slides (which do not show up on the video), and my written response. A synopsis of my major points is here:

Happer argues that the current concern over human-caused greenhouse gases is overblown.  Although he clearly understands basic climate science, his presentation includes claims that are exaggerated, misleading, or incorrect regarding human-caused climate change.  His presentation is entertaining, but he argues in many places against claims that climate scientists do not make.  He acknowledges that CO2 has an influence on climate, but emphasizes that the influence is small.  Yet he gives no physical reason to conclude that the current scientific understanding on the response of climate system to CO2 (the “climate sensitivity”) is wrong, other than to say that he does not trust climate models.  His claims that climate models do not work are exaggerated and misleading.  He also claims that increased CO2 will be beneficial by increasing plant growth – it is true that plant growth will increase by the CO2 increase alone, but he does not show that it will be beneficial, especially when climate is changing at the same time as CO2.  His presentation ignores the large number of studies available that show that through climate change, CO2 will be detrimental to agricultural productivity as well as to human well-being generally.

Since Happer has been giving similar lectures elsewhere, I was motivated to respond with what current science shows regarding his arguments – to encourage those who agree with Happer to consider what climate science tells us, and to give a stronger basis for those who agree with the scientific consensus on climate change to respond to his arguments.