“Is climate change a fact?” This was asked by moderator Tim Boyum at a Republican U.S. Senate primary debate. The four candidates replied, in succession, “No,” “No,” “No” and “No.” The entire exchange lasted 17 seconds. Climate change – that is, a change in the climate – has been a fact for decades. Average global temperatures are up about 1.5 degrees Fahrenheit since 1880, each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850 and the global average sea level has risen about 19 cm since 1901 (Intergovernmental Panel on Climate Change Fifth Assessment Report 2013).
If Boyum meant the question literally, then the four answers are wrong. If, however, he was asking something along the lines of, “Is it 100 percent certain that humans are causing climate change?” then the question is the wrong one to ask. The Nobel prize-winning Intergovernmental Panel on Climate Change, a collection of thousands of leading scientists and policymakers worldwide, recently stated in its Fifth Assessment Report tha,t “It is extremely likely that human influence has been the dominant cause of observed warming since 1950.” In the same report, they mention that by “extremely likely” they mean with greater than 95 percent probability.
No, this isn’t the same as 100 percent certainty. But since scientists deal with limited data, scientific claims are made not with total certainty but instead with very high probability. Every day, we all base important decisions about medical care, educatio, and parenting not on what we know with total certainty but on what we think is extremely likely. We know we might never have total certainty, and in the meantime there are consequences.
The IPCC cannot claim 100 percent certainty. However, its claim should be more than enough to expect that U.S. Senate candidates should seriously discuss climate change during a debate. North Carolina voters deserve this.
Dr. Robert J. Erhardt
Assistant professor of Mathematics, Wake Forest University
The length limit was waived.