On March 6th, assistant professor of mathematics, Dr. Rob Erhardt, addressed a full room of eager listeners on the topic of global climate disruption.  His talk, sponsored by the Math Club and titled Measuring Climate Change, drew a crowd from across campus, including Dr. Erhardt’s fellow Mathematics faculty, students, and staff members from the Office of Sustainability and the Wake Forest Humanities Institute.

Dr. Erhardt hoped to achieve two goals through his talk: “I wanted to show the Math Club students one way they could apply their mathematical education and I wanted to give a general talk about the science of climate change [for other members of the audience].”


The equation used by Dr. Erhardt in Measuring Climate Change.

The talk began with basic definitions of the words climate and climate change.  Dr. Erhardt, a statistician himself, proudly pointed out that the American Meteorological Association defines climate change as “any systematic change in the long term statistics of climate events (such as temperature, pressure, or winds) sustained over several decades or longer.”

After defining terms, Dr. Erhardt laid out the talk’s single equation: a calculation of Earth’s temperature based on the interaction of solar energy received by the Earth, reflectivity (the degree to which Earth reflects solar energy), and emissivity (the degree to which of Earth’s atmosphere allows radiated solar energy to escape into space).

Dr. Erhardt explained that, while solar input remains roughly constant, both the reflectivity of Earth’s surface and the emissivity of Earth’s atmosphere can change.  As Dr. Erhardt pointed out, these factors have changed since the mid-20th century, resulting in an overall increase in global surface temperatures.  Dr. Erhardt cited the conclusions of the most recent report by the Nobel Prize winning Intergovernmental Panel on Climate Change (IPCC), which stated “warming of the climate system is unequivocal” and attributed most of the increase in global average temperature to human beings, who have increased the atmosphere’s concentration of greenhouse gasses, changing the atmosphere’s emissivity.

Dr. Erhardt went on to discuss how global climate models can predict how much temperatures will rise in the future based on different scenarios.  He also reviewed current research trends, which involve creating regional climate models and grappling with the difficulty of “single event attribution,” or attempts to take one particular extreme weather event (like a hurricane) and determine if the changed climate has increased the risk of such an event.

“Climate science can be intimidating.  I wanted to present the science in an accessible, friendly way”, says Dr. Erhardt.  He explains, “People have a general respect for scientists, but I want them to understand a little bit more about what climate scientists are actually doing, like where they are getting their data and how they are using it.”

On March 27th, Dr. Erhardt will deliver Measuring Climate Change at a brown bag lunch for the Biodiversity and Environmental Science group of the WFU Center for Energy, Environment, and Sustainability.

 By Annabel Lang, Wake Forest Fellow for the Office of Sustainability